Dr Babak Mokhtarani

New pilot-scale experimental data are reported for hematite reduction with hydrogen in an indirectly heated flash reactor, named the Zero Emission Steel Technology (ZESTY) reactor, together with analysis with a one-dimensional well-stirred reactor and kinetic model. The process feeds particles by gravity through a tubular reactor, which is indirectly heated through the walls that are maintained at a range of uniform temperatures from 850 to 1100¿°C to achieve metallization of up to 95 pct. Process modeling is performed with Aspen Plus utilizing two kinetic models, namely the modified Sohn and mixed control models, together with a number of assumptions. The kinetic parameters are then adjusted with experimental data to best match the measured conversion. Calculations for hematite particle residence times consider particle velocity within the reactor, alongside particle size with the density modified to account for conversion extent. The modified model provides a reasonable match of the increase in the metallization degree of hematite with rising temperatures across the range of operating conditions. Moreover, elevating the hydrogen stoichiometric ratio correlates with increased metallization degree. Also as expected, an increase in the particle size adversely influences the metallization degree through decreasing the residence time. The level of agreement and internal consistency increases confidence in the reported results and interpretation of the measurements.

A comprehensive research study was conducted to examine the synergistic properties of ionic liquids, and hydrogels. Two nanocomposite hydrogel samples were created: one with ionic liquid and the other without. The samples were made using hydrogel with acrylamide (AM) backbone, Al2O3 nanoparticles, and ionic liquid [C8mim][NO3]. The effectiveness of a nanocomposite hydrogel containing an ionic liquid was tested to improve the wettability alteration and sweeping efficiency of reservoirs. Various tests were performed including IFT, electroconductivity, micromodel, SEM, and equilibrium swelling tests. The tests showed that the presence of the ionic liquid increased the swelling up to 102 %. IL increased conductivity by 124.24 % and 44.86 % at ambient temperature and 90 °C respectively. In the strain sweep test, the maximum elastic modulus for NCH-IL was recorded as 40,350 Pa, while for the sample without ionic liquid, it was 27,100 Pa. The frequency sweep test confirmed the three-dimensional structure of the gel. IL increased the maximum elastic modulus from 13,200 Pa to 27,400 Pa. The critical frequency value also increased by 87.5 %. Moreover, the suspension, which contains 1 wt% of Nanocomposite Hydrogel based on Imidazolium Nitrate Ionic Liquids, has shear-thinning properties, making it easy to inject into reservoirs. The reduction of the contact angle from 109° to 14.2° demonstrated the ability of IL to alter the wettability of NCHs. This result stemmed from the release of part of the ionic liquid within the hydrogel structure, as confirmed by the UV test. During the emulsion stability test, it was observed that the NCH-IL sample created a stable emulsion and a more complete two-phase separation than the sample without the ionic liquid. The sample that contained IL recorded 85 % and 78.4 % oil recovery in homogeneous and heterogeneous micromodels, respectively. Whereas, the sample without IL recorded 71.27 % and 60.73 % in the same micromodels.

The liquid¿liquid equilibrium (LLE) data for the ternary systems of (acetonitrile (ACN) + water (W) + choline chloride (ChCl)) and (ACN + W + water-based deep eutectic solvent (WDES) consisting of ChCl:W (1:3)) were measured at 298 K. The consistency of tie-lines was verified by the Bachman and Othmer¿Tobias correlations. ChCl as an organic salt and its WDES (within the water content range of less than 50 w%) as green extractants represent feasible performances in terms of selectivity and distribution coefficients for separation of water from acetonitrile-water system in comparison to other inorganic salts and hydrophobic DESs. ChCl in the (ACN + W + ChCl) system can separate water from the solution in the form of hydrate ions while WDES in the (ACN + W + WDES) system tends to absorb water by intermolecular forces. The experimental data of the (ACN + W + ChCl) system was correlated using the symmetric electrolyte non-random two liquid (e-NRTL) model while the equilibrium data of the (ACN + W + WDES) system was correlated using NRTL and universal quasi-chemical activity coefficient (UNIQUAC) models. ChCl in the form of salt represents a better separation performance than WDES for water removal from the acetonitrile mixture. Meanwhile, WDES might be considered to be superior compared to ChCl in terms of regeneration energy consumption and operating considerations.

Surfactants are used in many industries such as agriculture, petrochemicals, and bioremediation. Developing using greener products leads to garnering more attention to biosurfactants. The advantages of biosurfactants compared with chemical surfactants are proper biodegradability, less toxicity, environmentally friendly, and higher efficiency. However, high production costs and low yields are important problems in the economic production of biosurfactants. As a result, optimizing and increasing the production of biosurfactants are of great importance. In this study, continuous chemostat fermentation was used to raise process time, control the process parameters, and increase the efficiency of rhamnolipid biosurfactant by Pseudomonas aeruginosa HK02. First, the best carbon source, the concentration of the minerals in the feed, and the process parameters were determined. Then, experiments were done at different flow rates to determine the washout and optimal flow rate with high yield. The best source of carbon for this strain was sunflower and soybean oil. K S 6.63¿(g/L) and µ max 0.0377¿(1/h) were obtained. The flow rate of 240¿mL/day with a yield(p/s) of 0.88¿(g/g) had the highest efficiency. The process was tested at a flow rate of 240¿mL/day for 30¿days. The washout flow rate was 600¿mL/day. The biosurfactant production reaches 200¿g/L at optimum condition. The produced biosurfactant was able to reduce the surface tension of water to 31¿mN/m at 450¿ppm. The results showed that the continuous fermentation process was more economical and suitable for large-scale production of rhamnolipid biosurfactants, because of high productivity, and the possibility of continuing the process for one month and more.

In this study, the adsorption of thiophene compounds (TCs), including thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT), from model fuels was investigated using modified activated carbon (AC). The model fuel, prepared as a single-solute model at a concentration of 2000 ppm based on a mixture concentration of 3000 ppm, served as the basis for the adsorption experiments. Additionally, an examination of thiophene adsorption from commercial fuels, specifically kerosene, was conducted. Experimental data were used to calculate correlated parameters of adsorption isotherms, kinetic models, and the Fisher factor. The pseudo-second-order model demonstrated the best fit to the experimental data. Notably, the adsorbent consisting of 10% Cu+ supported on acid-washed activated carbon (A1CN10) exhibited the highest adsorption capacity for TCs, achieving removal percentages of 78%, 96%, and 100% for T, BT, and DBT, respectively. Various methods were employed to investigate the physicochemical properties of the adsorbents, including N2 adsorption¿desorption surface analysis (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Furthermore, the regeneration of the adsorbent was studied using two techniques: agitation and ultrasound.

Performance analysis of the adsorptive separation of ethylene downstream of an oxidative coupling of methane (OCM) process, being an alternative process for converting methane content of natural gas or other methane-rich sources to ethylene, was studied in this research for a production capacity of 1 Mt/yr. This was motivated by observing promising adsorption characteristics and efficiency in the selective adsorption of ethylene using 13X zeolite-based sorbent. The energy and economic performance of alternative scenarios for retrofitting the adsorption unit into an integrated OCM process were analyzed. Simulations of the integrated OCM process scenarios include OCM unit, CO2-hydrogenation, ethane dehydrogenation and methane reforming sections. The use of efficient ethylene adsorption separation enabled the improvement of the economic and energy efficiency of the integrated OCM process under specific operating conditions. For instance, the invested amount of energy and the associated energy cost per ton of ethylene in the cryogenic ethylene-purification section of the integrated process using adsorption unit are, respectively, 75% and 89% lower than the reference integrated OCM process. Under the conditions considered in this analysis, the return on investment for the final proposed integrated OCM process structure using adsorption separation was found to be less than 9 years, and the potential for further improvement was also discussed.

Adsorbents are developing in the various separation industries; these adsorbents can use to sweeten natural gas and remove hydrogen sulfide. Many commercial adsorbents are not regenerable when exposed to hydrogen sulfide because hydrogen sulfide is highly reactive. For H2S removal, the main challenge when using surface adsorbent, is the dissociation adsorption of H2S and non-regenerability of adsorbent. In this study, ultra-stable Y (USY) zeolite, was chosen to adsorb hydrogen sulfide due to its unique physical and chemical properties. To accurately model the adsorption isotherms, experimental adsorption data were measured in high pressure up to 12 bar for hydrogen sulfide and 21 bar for carbon dioxide, methane, and nitrogen as other natural gas components. The experiments were performed at three temperatures of 283, 293 and 303 K. Toth model fitted the experimental data very well, and the capacity of hydrogen sulfide adsorption on USY at the temperature of 283 K and pressure of 12 bar is 4.47 mmol/g that is noticeable. By performing ten cycles of adsorption and regeneration of hydrogen sulfide on USY, the regenerability of the adsorbent was investigated and compared by conducting a similar test on commercial 13X adsorbent. USY is found to be completely regenerable when exposed to hydrogen sulfide. The Isosteric adsorption heat of hydrogen sulfide on the adsorbent is 18.1 kJ/mol, which indicates physical adsorption, and the order of adsorption capacity of tested compounds on USY is H2S > CO2»CH4 > N2.

Air pollution has been integrated into global challenges over the last few years due to its negative impact on the health of human beings, increasing socio-economic risks, and its contribution to climate change. This study attempts to evaluate the current status of Iran's air pollution with regard to the sources of emissions, control policies, and the health and climate consequences that have resulted through available data from monitoring stations reported in the literature, official documents, and previously published papers. Many large cities in Iran surpass the permissible concentration of air pollutants, particularly particulate matter, sulfur dioxide, black carbon, and ozone. Although regulations and policies are in place and enormous efforts are being made to address air pollution issues in the country, implementation and enforcement are not as effective as they could be. The significant challenges may be regarded as the inefficiency of regulation and supervision systems, the lack of air quality monitoring systems and technology, particularly in industrial cities rather than Tehran, and the lack of continual feedback and investigations on the efficiency of regulation. Providing such an up-to-date report can bring opportunities for international collaboration, which is essential in addressing air pollution worldwide. We suggest that a way forward could be more focused on conducting systematic reviews using scientometric methods to show an accurate picture and trend in air pollution and its association in Iran, implementing an integrated approach for both climate change and air pollution issues, collaborating with international counterparts to share knowledge, tools, and techniques.

Biosurfactants can enhance oil recovery by decreasing the interfacial tension between water and oil, and altering the rock's wettability. In this study, the effect of two low molecular-weight glycolipid biosurfactants (rhamnolipid and sophorolipid) on enhancing oil recovery was investigated. The biosurfactants were economically produced from waste sunflower oil. The qualitative oil dispersion experiments were used to evaluate the biosurfactants' ability to separate oil, Surface tension and interfacial tension tests were carried out at various salinity rates. The potential of rhamnolipid and sophorolipid solutions to alter carbonate rock from an oil-wet state to a water-wet state was studied using the wettability test by measuring the contact angle. Moreover, the effect of rhamnolipid and sophorolipid biosurfactants on breaking the emulsion and improving the sweeping efficiency in porous media was investigated and compared using the micromodel test. Then three distinct homogeneous, heterogeneous, and layered patterns were created and tested in order to completely investigate the difference in oil displacement mechanism in three micromodels, and the impacts of the biosurfactant injection zone's permeability on oil recovery to design injection well patterns. The test results showed that these two biosurfactants were effective at separating crude oil from water. It was further observed that the rhamnolipid solution at 1000 ppm concentration and 60,000 ppm salinity reduced the interfacial tension to 5.42 mN/m, and the sophorolipid solution at 5000 ppm concentration and 80,000 ppm salinity reduced it to 7.93 mN/m. The rhamnolipid solution increased the contact angle between the oil drop and the carbonate rock from 41.42° to 109.26°, and the sophorolipid solution increased it from 32.16° to 104.12°. Also, the micromodel flooding test confirmed that in the case of rhamnolipid solution at the optimal concentration and salinity, the amount of oil recovery was measured as 80, 70, and 74% in the homogeneous, heterogeneous, and layered micromodels, respectively, while for the sophorolipid solution at the optimal concentration and salinity, it was recorded as 71, 61, and 69%, respectively. The micromodel results did not prove the fingering phenomenon under injection of either rhamnolipid or sophorolipid. Furthermore, proper distribution and breaking of the emulsion into micron size were confirmed. Accordingly, one can conclude that both surfactants (rhamnolipid and sophorolipid) have the potential to be utilized in oil field operations.

Ionic liquids (ILs) are a growing trend in Enhanced Oil Recovery (EOR) studies as alternatives to commercial surfactants due to their environmentally friendly nature, and their resistance in harsh temperatures and salinities. ILs are customizable and come in an immense variety, and therefore, it is vital that different combinations of cation/anion be investigated for use in the industry. In this work, experiments are designed and performed to evaluate novel ILs' surface activity and performance in a lab-scale EOR set-up, compatible with Iranian oil reservoir conditions. Three imidazolium-based ionic liquids were used, namely, butyl-methylimidazolium nitrate, hexyl-methylimidazolium nitrate, and octyl-methylimidazolium nitrate. Nitrate anions have a less environmental impact than the often-used halogen anions, but their performance in EOR have not yet been investigated. Aqueous and saline solutions of these ILs were prepared, and subsequently, interfacial tension (IFT) tests and emulsion stability tests were carried out while the IL concentrations were kept to a minimum to account for the procedure's feasibility. A high reduction in IFT between the saline IL solution, [C8MIm][NO3], and oil was observed compared to ILs with similar alkyl chain length in previous studies. Glass micromodels are exceptional in representing oil reservoirs under chemical EOR, and thus, were utilized to predict the ILs' contributions to sweep efficiency and recovery factor. Up to 80% oil recovery was obtained in the micromodel flooding tests with a strong sweep efficiency. Tests were repeated at two different temperatures (30 and 75 °C) and several salinities, and it was concluded that the ILs are resistant to harsh reservoir conditions, and can, potentially, improve the production efficiency of oil fields.

Today, the amount of nitrate (NO3-) and nitrite(NO2-) anions as the last step in the oxidation of the nitrogen compounds are important chemical indicators of water pollution. The presence of nitrates in water causes illness. Removing these anions is costly due to the high solubility in the water. Numerous methods have been used to remove nitrates. Some problems with these methods include cost, low efficiency, interference of other ions, high power consumption, destroying electrodes, membrane obstruction and the need for an operator. However, using adsorbents is a convenient method to remove nitrate. In this study, the adsorption with the aid of the Purolite A520E resin, which is functionalized using magnetic iron oxide nanoparticles, is used to remove nitrate. In order to activate the resin, it was rinsed with acid and base and used as a powder with dimensions of less than 120 µm. Using experiment design, the optimum condition was obtained which was pH 6 and 60 min in the ambient temperature. To study the adsorption thermodynamics, the Langmuir and Freundlich adsorption isotherm was investigated. It was observed that the nitrate adsorption model of the resin had better agreement with the Langmuir model. The resin affinity for nitrate ion was compared with that of the other ions, It follows the pattern NO3- > SO4-2> cL-. Reuse of the recovered resin after 7 periods showed satisfactory results. FTIR, VSM, XRD, EDAX and SEM have been used to characterize the magnetic resin.

The adsorption of acid gas, including hydrogen sulfide and carbon dioxide, by superhigh silica ZSM-5 was investigated. Equilibrium adsorption isotherms of high-purity hydrogen sulfide and carbon dioxide were measured experimentally using this new sorbent. In addition, methane and nitrogen adsorption isotherms on this MFI-type zeolite were also measured as representative of other natural gas components. To enhance the reliability of the results, the adsorption pressure has been selected up to 20 bar at three different temperatures. Superhigh silica ZSM-5 for the adsorption of hydrogen sulfide shows an impressive result of 3.04 mmol·g-1 at 12 bar and 283 K. This value was 2.69 mmol·g-1 for carbon dioxide at 21 bar and 283 K. The adsorption capacity of H2S on the ZSM-5 is the highest, and N2 is the lowest; the order of the adsorption capacities of components is H2S > CO2 > CH4 > N2. The adsorption heat of different adsorbates is calculated: 13.7 and 29.5 kJ·mol-1 for H2S and CO2, respectively. Physical adsorption has occurred on high-silica ZSM-5, especially for hydrogen sulfide, and this is a great advantage. By increasing the temperature, the adsorption capacity of components on the ZSM-5 decreases, but due to differences in the adsorption heat of the adsorbate, the ideal selectivity for hydrogen sulfide increases. There is a challenge in the choice of the best condition for H2S removal, as, by increasing the temperature, the adsorption capacity of hydrogen sulfide reduces, but the selectivity of the hydrogen sulfide increases as compared to other gases. This phenomenon is not true for the selectivity of other components.(Figure Presented).

In the present study, the production of cellulase by Trichoderma reesei under solid-state fermentation of nettle biomass was promoted through supplementation of the culture media using carbonaceous additives and comprehensive optimization of the cultivation via the Taguchi method. CMCase activities about 5.5¿6.1 U/gds were obtained by fermentation of the autoclave-pretreated biomass, among various chemical and physical pretreatments. Then, several additives including Tween 80, betaine, carboxymethyl cellulose, and lactose were individually or in combination added to the culture media to induce the enzyme production. The results proved that such additives could act as either inducers or inhibitors. Furthermore, CMCase activity surprisingly increased to 14.0 U/gds by supplementing the fermentation medium with the optimal mixture of additives including 0.08 mg/gds Tween 80, 0.4 mg/gds betaine, and 0.2 mg/gds carboxymethyl cellulose. Factor screening according to Plackett¿Burman design confirmed that the levels of Urea and MgSO4 among basal medium constituents as well as pH of the medium were significantly affected CMCase production. By optimizing the levels of these factors, CMCase activity of 18.8 U/gds was obtained, which was noticeably higher than that of fermentation of the raw nettle. The applied procedure can be promisingly used to convert the nettle biomass into valuable products.

Solubility of CO2 in the hybrid solvents composed of aqueous N-methyldiethanolamine (MDEA) blended with 1-methyl-3-octyl-imidazolium tetrafluoroborate ([Omim][BF4]) ionic liquid (IL) was measured at temperatures from (298.15¿343.15 K) and pressures of (0.2¿4 MPa). The experimental trials were performed in a static high pressure equilibrium cell to determine the CO2 absorption capacity of novel absorbent solutions based on the isochoric saturation technique. The experimental data showed that, by rising the concentration of IL in the absorbent solutions', the mole fraction of dissolved CO2 gas enhances gradually. Absorption capacity of these aqueous solutions was assessed and compared with pure ILs and alkanolamine solvents, which indicates the solutions studied in this research as better hybrid solvents in terms of CO2 loading. Furthermore, a semi empirical model is used to correlate the solubility data of this work, which presents a good agreement with an absolute average deviation (AAD %) of below 1%.

Developing an efficient sorbent and adopting an ethylene adsorption separation unit in downstream of an oxidative coupling of methane (OCM) process were the main focus of the present study. Since the mole fraction of the generated ethylene in the OCM reactor outlet is relatively low, the processing cost of the accompanying components and thereby the separation cost per ton of ethylene using the conventional cryogenic separation are insupportable. Zeolite 13X was modified in this research, demonstrating outstanding ethylene adsorption capacity and selectivity. The conducted adsorption experiments at a miniplant-scale unit enabled monitoring the adsorption breakthrough times and measuring the sorbents' capacity under different operating pressures in the range of 1-5 bar while processing different feed flow and feed compositions, representing the attachment of the adsorption unit to different parts of the OCM process. The modified zeolite 13X showed superior performance than the reference sorbents such as zeolite 4A and activated carbon. Physical treatment of zeolite 13X, by calcining it at 550 °C, proved to be efficient in increasing its adsorption capacity. Chemically treating zeolite 13X via copper exchange on the other side increased its ethylene adsorption selectivity in competition to CO2 adsorption. In processing the CO2-rich feed streams (with the CO2 content 2.25 times of its C2H4 content), the Cu-exchanged zeolite 13X showed a promising ethylene adsorption capacity of 0.46 molC2H4·kgs-1 combined with an adsorption selectivity of 0.45 molC2H4·molCO2. In processing the CO2-free feed streams (with the C2H4 content 2.75 times of its C2H6 content), using the calcined zeolite 13X secured the highest adsorption capacity of 1.4 molC2H4·kgs-1 along with an adsorption selectivity of 3.8 molC2H4·molC2H6 under 5 bar adsorption pressure. These indicate the promising potentials of the developed sorbents and the designed adsorption unit for processing the OCM reactor outlet gas stream before and after removal of its CO2 content.

The aim of this paper is to modify the X zeolite adsorbent to enhance nitrogen adsorption capacity. To this end, a novel procedure for modification of X zeolite, including both NH4+ treatment and Ca2+ ion-exchange, is introduced which results in a hierarchical mesopore-micropore structure with multilayer N2 adsorption behavior. The presented adsorbents, "hierarchical X zeolite" (HX) and "Ca2+ exchanged hierarchical X zeolite" (CaHX), are compared with the available microporous 13X zeolites, modified by Na+ (NaX), and mixed Ca2+ /Na+ cations (CaNaX). The properties of these adsorbents are characterized by N2 adsorption¿desorption in 77 K, XRD, and XRF analysis. The high-pressure N2 adsorption isotherms are measured at 283, 298, and 313 K up to 35 bar. It is shown by increasing the pressure, N2 adsorption capacity of HX and CaHX continuously increases (without saturation), in comparison with NaX and CaNaX that approaches to a saturation point. The N2 adsorption capacity of CaHX is 4.70 mmol/g at 35 bar and 298 K, which is 57% and 102% more than CaNaX (2.98 mmol/g) and NaX (2.33 mmol/g), respectively. Considerable potential improvements in the N2 adsorption capacity of CaHX are explained by the multilayer adsorption of N2 at high pressures in mesopores, as a dominant mechanism. Additionally, the isosteric heat of adsorption of hierarchical X zeolites (HX and CaHX), calculated by Clausius-Clapeyron equation, are lower than NaX and CaNaX that leads to the more facile regeneration. Adsorption isotherms are also modeled by Langmuir, Dual-Site Langmuir (DSL), Freundlich, and Langmuir-Freundlich (Sips) models, and related parameters determined. These adsorbents can be used effectively in the helium purification by the PSA process, which is based on nitrogen adsorption.

Macrocyclic calix[4]arene molecules were immobilized onto silica surface and shown to be highly selective hybrid adsorbents for CO2 capture application. These hybrid adsorbents were prepared by immobilization of various calix[4]arene molecules, with differing upper rim functional groups: tert-butyl, amine, and calix[4]arene, onto surface of silica gel through 2,4-toluene diisocyanate (TDI) linker. Synthesized hybrid materials were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, nitrogen adsorption¿desorption measurements, scanning electron microscopy and elemental analysis. Single component adsorption of pure gas CO2, CH4 and N2 were measured experimentally at three different temperature and pressure up to 30 bar using the volumetric method. Among all the materials, amino functionalized calix[4]arene, with calixarene loading of (~0.21 mmol g-1), exhibited improved CO2 uptake as well as exceptionally high ideal adsorption selectivity (CO2:N2 = 443) and (CO2:CH4 = 148) at 25 °C and 1 bar, mainly due to the presence of amine functional groups. Moreover, for investigating the affinity between CO2 and adsorption sites, isosteric heat of adsorption were calculated by Clausius¿Clapeyron equation. Results of systematic experimental investigation in this report may pave the way toward later studies on these promising highly potential hybrid adsorbents in CO2 adsorption field area, according to their unique properties and designable structure.

Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phe-nols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating condi-tions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive po-tentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly cat-alyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

New experimental data for adsorption of ethylene and ethane on zeolite 13X and zeolite 5A are reported at a temperature range of 288-308 K and pressure up to 20 bar. The cation exchange for zeolites 13X and 5A was performed using copper, and the observed adsorption capacities of the copper-exchanged zeolites were measured. The equilibrium adsorption capacities of these adsorbents toward ethylene and ethane were compared. The copper-exchanged zeolites showed improved adsorption capacities toward both gases, where CuA was found to have the highest adsorption capacity. However, the copper-exchanged zeolites 13X and 5A underperformed in comparison to the expected high selectivity for ethylene/ethane separation. The data utilized for expressing the adsorption isotherm were successfully correlated with the Toth model, and the parameters for this model were calculated as reported in this paper.

Conventional flocculants bear environmental and health concerns which could be avoided by applying natural materials, particularly polysaccharide and glycoprotein-containing ones. In the present study, yeast cell wall (YCW), a natural polymer matrix, was used as natural flocculant. To prepare YCW, Saccharomyces cerevisiae was cultivated in bench scale fermenter. After characterization, YCW was employed as anionic flocculant in jar tests to remove turbidity from kaolin suspensions at different conditions where either alum or poly aluminum chloride (PAC) was coagulant. Generally, the lower coagulant consumption, higher turbidity removal or faster sedimentation was observed by using YCW as flocculant. The developed flocculant was more effective in the presence of PAC compared to alum. At best, by applying 300 mg/L YCW, the highest turbidity removals of 98 and 97% were achieved using 10 ppm PAC at pH 6.5 and 50 ppm alum at pH 7.5, respectively. The presence of the flocculant in the structure of the flocs was proved by FTIR analysis. The final pH of the treated suspensions was suitable for discharge purpose without the need for neutralization. The excess positive charge neutralization and bridging were the governing mechanism in coagulation-flocculation process. YCW with proper performance, GRAS designation and readily availability can be considered as natural alternative to chemical anionic flocculants where the process needs safe compounds.

The performance of two tetrafluoroborate-based ionic liquids (ILs) as entrainers in the dehydration of water/ethanol azeotropic mixtures was evaluated. Isobaric vapor-liquid equilibrium (VLE) data were measured for the systems ethanol/water/1-butyl-3-methyl imidazolium tetrafluoroborate and ethanol/water /n-butylpyridinium tetrafluoroborate including the azeotropic region. VLE data for the ethanol/water, ethanol/IL, and water/IL binary mixtures were obtained at 100 kPa. The hydrolysis of the tetrafluoroborate anion was studied for both types of ILs by 19F NMR analysis. The hydrolysis of the tetrafluoroborate anion does not have much effect on the ethanol/water VLE. The 19F NMR analysis indicated that hydrolysis occurred at high mole fractions of water.

Extractive-catalytic oxidative desulfurization (ECOD) technology is a potential industrial application for attaining low-sulfur fuel oils. In this research, novel graphene oxide (GO)-based heterogeneous catalysts were synthesized by immobilization of different amounts of phosphotungstic acid H3PW12O40 (HPW) on GO. The obtained HPW-GO catalysts were characterized by FT-IR, SEM, EDX, TEM, AFM, and RAMAN analyses. The ECOD was applied for removal of dibenzothiophene (DBT) from a model fuel with H2O2 as the oxidant, acetonitrile as the extracting solvent, and HPW-GOs as the catalysts. Among the catalysts with different HPW contents (5, 10, 20, 25, 30, 40 wt%), the catalyst with 40 wt% HPW had the best performance. The optimum reaction time, temperature, H2O2/sulfur molar ratio (O/S) as well as the kinetic parameters (kinetic constants and apparent activation energy) were evaluated. 100 percent desulfurization yield was achieved in a short time (t = 30 min) using the 40 wt% catalyst under moderate conditions (catalyst loading = 5 g/l, O/S = 6, T = 333 K). Aiding by synergism, the heterogeneous HPW-GO catalyst showed a higher desulfurization yield compared to that by the homogeneous HPW. The reactivity of 4,6-dimethyldibenzothiophene (4,6-DMDBT) in the ECOD process was found to be equal to that of DBT but much higher than the reactivity of benzothiophene (BT) within 60 min. The catalyst could be recycled for eight times without significant decrease in activity. A reasonable reaction pathway was proposed based on the GC¿MS analysis. Almost all of the sulfur content of a real fuel could be completely oxidized and removed by the ECOD. Comparing to the results reported in literature, the features of proposed one-step fast ECOD process, which requires very low catalyst at moderate conditions for complete desulfurization without any phase transfer agent, makes it distinctive for practical applications.

Experimental data for adsorption of pure carbon dioxide, methane, and nitrogen on zeolite 13X granules at different temperatures (288.15-318.15 K) and pressure up to 20 bar are reported. The cation of adsorbent is exchanged with H+, Li+, and Cu2+, and the adsorption of pure gases is measured. The equilibrium adsorption isotherms of gases are performed with a static volumetric adsorption instrument, which was designed and built. The results show that the adsorption capacity of carbon dioxide is higher than that of methane and nitrogen and that the cation exchange improved the adsorption capacity of pure gases. The LiX adsorbent has the highest adsorption capacity among the studied adsorbents. However, the relative selectivity of carbon dioxide over methane for zeolite 13X has the highest value of 30.48. The CuX adsorbent shows the highest selectivity for carbon dioxide over nitrogen. The adsorption isotherms for all of the pure gases are fitted successfully with the Toth model.

Rhamnolipids are one of the most well-known classes of biosurfactants having wide applications in various industries due to low toxicity, high biodegradability, and environmentally friendly. Dissolved oxygen (DO) concentration has the crucial effect on rhamnolipids production, particularly through fed-batch cultivation. In this study, the effect of different levels of DO concentrations on rhamnolipid production by Pseudomonas aeruginosa in both batch and fed-batch fermentation was investigated in a lab-scale fermenter under precise DO control. A maximal rhamnolipid production of 22.5¿g/l was obtained at a DO concentration of 40% in batch fermentation. In order to achieve the high rhamnolipid production, a fed-batch operation under tight DO control of 40% was conducted. As a result, the overall rhamnolipid production and productivity reached to 240¿g/l and 0.9 (g/l¿h), corresponding to a 10.7 and 4.8-fold improvement compared to the batch experiments. The high level of rhamnolipid production via the fed-batch cultivation can be attributed to both DO concentration and the feeding strategy. This achievement is promising for the production of rhamnolipid in industrial scale.

Improving the production of lignocellulose-degrading enzyme such as cellulase and xylanase substantially increases the chance for cost-competitive production of cellulosic biofuel and other chemicals from such a biomass. In this study, the possible effects of carbonaceous additives including Tween 80, betaine, carboxymethyl cellulose (CMC) and lactose on cellulases and xylanase production were investigated individually or in combination. The enzymes were produced by Trichoderma reesei in solid state fermentation of wheat straw, wheat bran, rice straw and rice husk. The results proved that an individual additive could be an inducer or inhibitor based on the type of carbon source and targeted enzyme. For applying additives in combination, their roles depended on not only the type of carbon source and targeted enzyme but also their concentrations. Furthermore, a single additive with inhibitory role could be an inducer in combination with the other additives. For the best induction, the xylanase activity was about 469 U/gds with betaine as a single inducer. It increased to 218% with the mixture of Tween 80, betaine and CMC, supporting the combination of additives is more inducing. Applying the mixture of inducers can highly improve the process efficiency in lignocellulose-based biorefineries for both fuel and chemicals production.

Different tungsten and molybdenum containing heteropolyacid (HPA) catalysts (H 3 PMo 12 O 40 :Mo 12, H 3 PMo 8 W 4 O 40 :Mo 8 W 4, H 3 PMo 6 W 6 O 40 :Mo 6 W 6 , H 3 PW 12 O 40 :W 12 ) were immobilized on graphene oxide (GO) to obtain HPA¿GO heterogeneous catalysts (Mo 12 ¿GO, Mo 8 W 4 ¿GO, Mo 6 W 6 ¿GO, and W 12 ¿GO). The synthesized catalysts were applied in removal of sulfur containing compounds [benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT)] with combined extraction¿oxidation process using a batch reactor. The sulfur removal efficiency was gradually increased with increasing the ratio of molybdenum ions in the HPAs and complete sulfur removal efficiency for DBT was obtained for Mo 12 ¿GO. The roles of affecting parameters such as extracting solvent, catalyst calcination, and feed concentration were also investigated. Among different extracting solvents including acetonitrile, DMF, NMP, methanol, water, and ethylene glycol, acetonitrile represented the best ECOD performance as the extracting solvent. The performance of non-calcined catalyst for sulfur removal was slightly better than that by the calcined one. It was also found that the high sulfur removal activity of the extractive-catalytic oxidative process (ECOD) was retained even at high feed concentration. The kinetic model was evaluated considering mass transfer coupled with chemical reaction, in which the catalytic oxidation reaction was recognized as the rate-controlling step. The kinetic parameters such as rate constants and apparent activation energy were determined.

This paper presents research on the supersonic nozzle geometry with particular emphasis on the effect of the internal body of the nozzle that largely affects the separation efficiency. A numerical investigation of the supersonic nozzle with an internal solid body, which forms an annular flow inside the convergent¿divergent nozzle is carried out. The present study revealed different hydrodynamic behaviors of the nozzle, exploring different shapes of the inner body, and the computational fluid dynamic simulations of the supersonic nozzle is utilized to find out the best geometrical design. Utilizing a coupled pressure¿velocity scheme with high order of discretization of the governing equation yielded to find the shockwave positions in different conditions. The turbulent behavior of the fluid in the shockwave zone is well discussed and the phase-change phenomena for the natural gas application are studied considering both water condensation and hydrocarbon condensation simultaneously. Different nozzle configuration elucidates the physical mechanisms of the supersonic flow inside the nozzle. Shockwave position, swirling velocity stability, and mass flow capacity are investigated. The lower the inner body radius, the less the change of shockwave position in the gas is found. Also, the higher stability of swirling velocity magnitude is found for the convergent¿divergent inner body, which brings enhanced physical phase separation.

An efficient lipopeptide biosurfactant (BS) producer, Aneurinibacillus thermoaerophilus HAK01, was isolated from municipal landfill sites. The strain was able to produce about 4.9 g L-1 lipopeptide at a thermophilic temperature of 45 °C. After optimization of culture component concentrations using the response surface method, the main focus is to find the most appropriate fed-batch strategy to enhance lipopeptide production by the HAK01 strain. For this purpose, four fed-batch strategies including (a) pH-stat mode, (b) constant feeding rate strategy, (c) DO-stat mode, and (d) combined feeding strategy were designed. The production of BS was increased systematically from 4.9 g L-1 in batch mode to 5.9, 7.1, 8.8 and 11.2 g L-1 in each fed-batch mode, respectively. While poor results were obtained in the pH-stat mode, the DO-stat mode showed excellent results in the production of BS. The results of the study confirmed the importance of operational mode, oxygen supply and the kind of feeding strategy in BS production.

New experimental data for CO2 solubility in the aqueous solutions of N-methyldiethanolamine (MDEA) and 1-butylpyridinium tetrafluoroborate ([Bpy][BF4]) ionic liquid (IL) are reported. The experiments were conducted in a static high pressure equilibrium cell. Solubility measurement of CO2 was performed in various solution compositions of IL and MDEA in a wide temperature range of 298.15-343.15 K and pressures up to 4 MPa. The experimental results revealed that, by increasing the weight percent of IL, the absorption capacity of aqueous mixtures diminishes. It was also observed that the main capacity of CO2 loading in the absorbent solutions belonged to MDEA through chemical absorption, whereas its concentration was more effective than IL in gas solubility. The experimental results are correlated using a semiempirical model with good accuracy.

Experimental data for solubility of CO2 and CH4 in 1-hexyl-3-methylimidazolium nitrate [Hmim][NO3] at temperature range of 293.15¿343.15 K and pressure up to 4 MPa are reported. The solubility of CO2 is higher than that of CH4 in the entire temperature region studied. The experimental data show that the temperature has a little effect on CH4 solubility. The Henry's constant of both gas in [Hmim][NO3] are calculated and the ideal selectivity of CO2 to CH4 are reported. The ideal selectivity is increased with temperature reduction. The experimental data for CO2 solubility are compared with other types of nitrate based ionic liquids (ILs) at different temperatures and pressure. The results of this comparison reveal that the solubility of CO2 is increased with enlargement the alkyl chain length of IL cation. The experimental data are correlated with the extended Henry's law model. The virial expansion model of Pitzer is used for interpretation of the activity coefficient of the gases and the interaction parameters of the model are estimated as a function of temperature.

An experimental study on the isobaric vapor¿liquid equilibria for the ternary system of acetone + methanol + 1-methyl-3-octylimidazolium thiocyanate ([Omim][SCN]) as well as the two acetone + ionic liquid (IL) and methanol + IL binary systems was performed at 100¿kPa using a recirculating still (VLE 602 Fischer apparatus). A low IL mole fraction of 0.027 was found to be sufficient break the azeotrope due to the high and specific interactions with acetone and methanol. The nonrandom two-liquid model was used to represent the experimental data. The results are compared with those in the literature for the same mixed solvent system using other ILs.

The experimental liquid ¿ liquid equilibrium (LLE) data for three ternary mixtures containing an ionic liquid (IL) (1-butyl-3-methyl imidazolium thiocyanate [Bmim][SCN]), alkanes (n-hexane, n-octane and n-decane) and sulfur compound (thiophene) have been measured experimentally. Distribution and selectivity coefficients have been calculated using experimental data. The LLE data have been obtained at 25 °C and ambient pressure. The experimental LLE data of ternary mixtures have been compared with our previous works. It has been shown that the IL with higher molecular weight of cation has higher solute distribution and lower selectivity coefficients. It has been found that the solubility decreases as the cation length decreases, meanwhile ILs cation chain length has a remarkable effect on solubility of alkanes. Moreover, the experimental data have been demonstrated that the selectivity decreases as alkane chain length of alkane decreases while the solubility of alkanes in the ILs increases, hence the removal costs of aromatic sulfur components will be increased. The results show that [Bmim][SCN] has the lowest alkane solubility and highest selectivity coefficient, in the system containing n-decane and thiophene. A comparative study reveals that compared to other ILs, [Bmim][SCN] is a more suitable solvent. Finally, the experimental data have been correlated utilizing non-randomness two liquid (NRTL) model. The binary energy parameters were obtained, it can be seen that the model can correlate the experimental data efficiently.

Among microorganisms, bacteria are the main group of biosurfactant-producing organisms. Different types of bacteria including Pseudomonas sp., Acinetobacter sp., Bacillus sp., and Arthrobacter sp. are among the most commonly studied bacteria in the realm of scientific research. However, due to the pathogenic nature of the producing organisms, the application of these compounds is restricted, therefore, not suitable for use in food-related industries. Given that probiotic bacteria impact human health, applying probiotics as nonpathogenic and safe organisms have gained much attention for the production of biosurfactants in recent years. Most biosurfactants obtained from probiotic bacteria are related to a number of lactic acid bacteria (LAB). These types of biosurfactants are classified based on their structures as protein¿carbohydrate complexes, lipids, or fatty acids. The present paper seeks to provide comprehensive and useful information about the production of various kinds of biosurfactants by different probiotic bacteria. In addition, we have extensively reviewed their potential for possible future applications.

CO2 sorption capacities of the neat and silica-supported 1-butyl-3-methylimidazolium-based ionic liquids (ILs) were measured under atmospheric pressure. The silica-supported ILs were synthesized by the impregnation-vaporization method and charactrized by N2 adsorption/desorption and thermogravimeteric analysis (TGA). Evaluation of the effects of influential factors on sorption capacity demonstrated that by increase of the temperature, flow rate, and the weight percentage of ILs in sorbents, the sorption capacity decreases. Among the sorbents, [Bmim][TfO] and SiO2-[Bmim][BF4](50) had the highest capacity. By increasing the IL portion in SiO2-[Bmim][BF4], the selectivity for CO2 to CH4 could be improved. The CO2-rich sorbents could be easily recycled.

Aiming deep oxidative desulfurization, a novel heterogeneous catalyst of phosphomolybdic acid (H3PMO12O40, HPMo) supported on graphene oxide (GO) was synthesized. The characteristics of the catalyst and its performance in an extractive-oxidative desulfurization (ECOD) process were assessed. The effects of main process variables such as catalyst dosage, reaction temperature, oxygen to sulfur ratio (O/S), and extracting solvent to fuel volumetric ratio (E/F) on the responses including overall, extractive, and oxidative desulfurizations were measured and a detailed discussion about the influence of each process parameter on the three responses was performed. A novel approach was proposed to find the practical optimum conditions through combining two-phase mass balance along with applying central composite design method. Complete oxidative desulfurization was achieved in a short time (within 30 min) by low amount of the catalyst (2.5 g/l), O/S ratio of 6, temperature of 50 °C, and E/F of 0.3. Similar to dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT) could also be removed with desulfurization efficiency of 100%. The superior performance of the ECOD was interpreted in terms of catalyst properties and the characteristics of two-phase desulfurization system. HPMo-GO catalyst showed high durability even after six times recycling. A reasonable ECOD pathway was proposed using GC¿MS analysis. The results of proposed ECOD process were compared with previously reported ones.

Supersonic nozzles are recently applied for carrying out water separation from natural gas streams and dew pointing in early stages of gas processing. This paper represents an experimentally and numerically study on a novel low-pressure two-phase driven supersonic nozzle constructed based on a new annular design. The nozzle includes a set of tilted fixed blades at the entrance and a swirling stabilizer along with a convergence-divergence nozzle. The liquid phase is separated from the primary gas phase by decompression and compression happening accompanied with the centrifugal effect induced by the swirling of the gas stream. The phase change happens by gradual drops in temperature and pressure upstream of the shockwave position, and an abrupt change at the shockwave position followed by a subsequent gradual increase in temperature and pressure. The pressure, temperature, and moisture level of the gas are measured to investigate the performance of the supersonic separation unit. The computation is carried out by a 2D approach capable of two-phase heat and mass transfer modeling. For the first time, the analysis uses high order of discretization schemes in order to well capture the shockwaves in a low-pressure supersonic nozzle and find out their effects on separation. An assessment is carried out focusing on the effect of operational conditions on the nozzle performance. The experimental data for dehydration efficiencies are in good agreement with the simulation results within 3%. The shockwave position is found in the range of 0.3¿0.5 of non-dimensional nozzle length. The positions of both shockwave and initiation of condensation are shifted toward the exit side when the nozzle pressure ratio decreases. Reducing the pressure ratio from 0.8 to 0.6 will enhance the dehydration efficiency by about 5%.

A deep analysis on the hydrodynamics of convergent¿divergent nozzles is performed by changing the working conditions and fluid type. The nozzle geometry lowers the temperature of the flowing fluid, which contributes to condensation and phase change. The focus of this paper is to evaluate the nozzle performance and cooling capacity in terms of temperature, pressure, and gas type in a fixed geometry of Sajben Laval nozzle. The analysis has been conducted via a 2-dimensional turbulent computational fluid dynamics simulation for illustrating the behavior of the fluid. A criterion for the nozzle performance is provided by prediction of exact shock wave position. An investigation on 6 different gas types demonstrates that heat capacity and thermal conductivity are the most rolling fluid properties of the nozzle performance. Furthermore, it is found that the shock wave position is unchanged during alteration of fluid type or pressure scale. A new model is provided for prediction of convergent¿divergent nozzle performance in the supersonic conditions for dehydration of natural gas as a well-known industrial application of the nozzles. The model is developed by the genetic algorithm as a multivariable optimization method.

Low conversion efficiency and long-processing time are some of the major problems associated with the use of biocatalysts in industrial processes. In this study, modified magnetic iron oxide nanoparticles bearing tyrosinase (tyrosinase-MNPs) were employed as a magnetic nano-biocatalyst to treat phenol-containing wastewater. Different factors affecting the phenol removal efficiency of the fabricated nano-biocatalyst such as catalyst dosage, pH, temperature, initial phenol concentration, and reusability were investigated. The results proved that the precise dosage of nano-biocatalyst was able to degrade phenol at the wide range of pHs and temperatures. The immobilized tyrosinase showed proper phenol degradation more than 70%, where the substrate with a high concentration of 2500¿mg/L was subjected to phenol removal. The nano-biocatalyst was highly efficient and reusable, since it displayed phenol degradation yields of 100% after the third reuse cycle and about 58% after the seventh cycle. Moreover, the immobilized tyrosinase was able to degrade phenol dissolved in real water samples up to 78% after incubation for 60¿min. It was also reusable at least seven cycles in the real water sample. The results proved the effectiveness and applicability of the fabricated nano-biocatalyst to treat phenol-containing wastewaters in a shorter time and higher efficiency even at high phenol concentration. The developed nano-biocatalyst can be promising for the micropollutants removal and an alternative for the catalysts used in traditional treatment processes.

Liquid-liquid equilibrium data (LLE) for the mixtures of ionic liquid (IL) + alkane + aromatic {1-butylpyridinium nitrate, [BPy][NO3] (1) + heptane, octane, or decane (2) + ethylbenzene (3)} and {[BPy][NO3] (1) + heptane, octane, or decane (2) + p-xylene (3)} at T = 298.15 K and P = 89 Kpa were measured. The degree of reliability of the experimental LLE data was examined by using the Othmer-Tobias and Hand correlation. For the six studied ternary mixtures, the separation factor and distribution ratio of aromatic hydrocarbons derived from LLE data and were applied to determine if [BPy][NO3] can be used as dearomatization solvent. The separation of aromatic compounds with similar molecular weight (ethylbenzene and p-xylene) from alkanes demonstrates that p-xylene can be separated more easily from alkanes. The triangular phase diagrams for all studied systems were sketched, and the tie lines were compared with the NRTL model. (Graph Presented).

The thermal separation flow characteristic in a vortex tube using a three-equation turbulence model is discussed in the present research. Flow behavior and energy separation of a vortex tube in different boundary conditions are investigated through a 3D model. The effect of the operating parameters on the turbulent viscosity ratio and the Mach number is also discussed. It was found that strong swirling flows with a high order of tangential velocity in the peripheral flow contributes to the rise in temperature due to viscous heating. Energy separation and cold-end side temperature depend mainly on the ratio of cold and hot-end side mass flow rates and the inlet conditions. Moreover, the effect of back pressure at cold-end side was investigated to determine how it alters the performance of the vortex tube. Finally, the results of the proposed computational fluid dynamics model are validated by the available experimental data.

In this research, absorption of CO2 in different ionic liquids (ILs) is studied. Thus four ILs were synthesized containing 1-butyl-3-methylimidazolium as the cation and nitrate [NO3]-, thiocyanate [SCN]-, dicyanamide [N(CN)2]- and hydrogen sulfate [HSO4]- as the anions, respectively. The resulting ILs were then immobilized into activated silica support in a 1/1 IL/SiO2 weight ratio via the impregnation-vaporization method. CO2 sorption behavior of both neat and silica supported ILs (ILs-SiO2) were investigated at different temperatures and flow rates under atmospheric pressure, while their desorption process were carried out under 20¿mm¿Hg at 70¿°C. In both sorbents, the best results were obtained at 25¿°C with a flow rate of 12¿mL/min, where [bmim][N(CN)2] with 1.85 (wt%) or 0.42¿mmol CO2 per gram of sorbent and [bmim][HSO4]-SiO2 with 2.33 (wt%) or 0.53¿mmol CO2 per gram of sorbent showed the highest sorption capacities. The effect of water on CO2 absorption capacity of the neat and silica supported ILs were also studied by transmission of CO2 gas flue containing 400¿ppm water. The results indicated that the mass gain was higher when wet CO2 was passed through the sorbents, opposed to passing dry CO2. Because of the existence of a weak coulombic intraction between the sorbents and CO2, desorption occurs rapidly and a readily reuse of the sorbents is therefore provided.

Adsorption of tungstophosphoric acid (H3PW12O40) as a polyoxometalate (POM) on graphene oxide (GO) and two reduced graphene oxide supports (RGO-a/RGO-b) for producing supported catalysts was studied using an equilibrium adsorption technique by ultraviolet¿visible spectroscopy analysis. The surface properties of supports were analyzed by XPS to interpret their different adsorption properties. The samples were characterized by XRD, RAMAN, FTIR, SEM-EDX, and TEM analyses. The three most determinant parameters in adsorption phenomena are presence of oxygen functional groups on the support, the polarization of surface functional groups in accordance to the suspension pH, and the solvent type. The supported polyoxometalate on GO (GO/POM) prepared by adsorption in a suspension of 1:1 water/methanol mixture with pH = 3.5 yielded the highest adsorption capacity of 427 mg/g while the adsorption capacities of supported polyoxometalate on reduced samples were 74 mg/g and 54 mg/g, respectively. The pH-dependent behavior of ionizable surface oxygen functional groups was investigated and results revealed that also played a key role in the adsorption capacity. The highest POM adsorption was obtained in the pHs below isoelectric point of GO where POM anions can establish chemical bonds with the positive net surface charge. The highest adsorption capacity was obtained in the water-methanol mixture. The kinetics of adsorption mechanism was best described by a pseudo-second-order model.

Graphene was produced either by chemical reduction of graphene oxide (GO) using hydrazine hydrate (HG)/sodium borohydride (BG) or by straight electrochemically exfoliation of graphite (EG). The X-ray diffraction and Raman spectroscopy confirmed smaller in-plane crystalline sizes for the chemically produced graphenes, and more number of layers and therefore lower structural defects for the EG sample. The graphene samples were used to prepare polydimethylsiloxane (PDMS)¿graphene (G)/polyethersulfone (PES) hybrid membranes to investigate their pervaporative performances. All three produced hybrid membranes had better separation performances for removal of phenol from water in terms of phenol flux and selectivity compared to the unfilled membrane (1.3 g/m2 h and 11.09, respectively). An appropriate interfacial structure for the BG- and HG-filled membranes (having lower number of layers) was achieved at 0.2 wt% graphene content while for the EG-filled membrane, it was attained at 0.4 wt% graphene content. PDMS¿BG/PES had the highest phenol flux of 3.6 g/m2 h due to the lowest carboxylic functional groups and highest C/O ratio of the filler, and PDMS¿HG/PES had the best selectivity of 40.02 due to the lowest C/O ratio of the filler and hence the lowest water flux.

Sulfonated polyether sulfone-based cation-exchange membranes are prepared by incorporating different amounts of graphene oxide and sulfonated graphene oxide nanosheets. The graphene oxide nanosheets are synthesized according to Staudenmaier and Hummer methods and functionalized using 3-mercaptopropyl trimethoxysilane. Transport properties of nanocomposite membranes including ion-exchange capacity, transport number, and conductivity as well as their thermal stabilities are enhanced by incorporating sulfonated graphene oxide rather than graphene oxide. Also, the enhancement is more significant for the nanocomposites having functionalized graphene oxide synthesized by Staudenmaier method than those by Hummers method due to higher density of active sites in the Staudenmier graphene oxides for functionalization.

The Speed of sound is one of the most prominent parameters in the fluid dynamics and aerodynamic studies. A major challenge lies in the fact that two-phase region properties are dramatically different from the single phase condition and the simple models do not satisfy the adequate accuracy required for the sound speed prediction. The present research explores various attempts for calculating the speed of sound and suggests a new practical equation which is correlated with fluid properties and it is developed by genetic Algorithm. The obtained results are encouraging and the final derived model has the most accuracy for the two-phase region covering different types of thermodynamic processes. In addition, the new model and the classic 1D model are combined to perform an analysis of the role of the two-phase sound speed consideration. The temperature and the pressure profiles inside a converging - diverging nozzle are investigated, representing the phase-change phenomena inside the supersonic nozzle. The related Mach number and the nozzle performance are studied using the proposed model.

A novel heterogeneous catalyst was prepared by supporting the ionic liquid (IL) 1-octyl-3-methylimidazolium hydrogen sulfate ([Omim][HSO4]) in the silica-gel matrix using a sol-gel method and employed in oxidative desulfurization of a model oil containing dibenzothiophene (DBT) and real diesel fuel. The properties of the supported ionic liquid (SIL) were characterized by FT-IR, TGA, BET-BJH, SEM-EDS, and PSA. The results showed that the ionic liquid was successfully incorporated in the silica-gel matrix, and a catalyst having high surface area was prepared. The effects of H2O2/DBT molar ratio (O/S), temperature, SIL/oil mass ratio, initial S content, and sulfur species on the sulfur removal of the model oil were studied. The highest DBT removal efficiency of 99.1% was obtained with the prepared catalyst having 17 wt % supported IL loading in the conditions of SIL/oil (w/w) of 1:3 and O/S molar ratio of 5 in 50 min at 50 °C. The prepared catalyst can be efficiently applied in oxidative desulfurization with consumption of much lower IL compared to that in a desulfurization system using bulk IL. The order of oxidative removal efficiencies of different sulfur species is as follows: DBT > BT > TS > 4,6-DMDBT. The SIL can be separated by a simple filtration from the reaction system and reused four times without any significant decrease in its performance. A high sulfur removal of 75.7% was also obtained by applying the prepared catalyst in desulfurization of the hydrotreated real diesel fuel.

Tyrosinase is used to eliminate phenolic compounds from wastewater. Therefore, its immobilization is important to enhance catalytic efficiency. Papery materials are of particular interest for use as support for enzyme immobilization since the porous microstructure of fiber networks in papers can provide a suitable reaction environment, especially in flow-type catalytic reactions. However, immobilization of protein onto papery structure needs chemical modifications in severe conditions. To overcome this challenge, a cellulosic paper was directly amine-functionalized in moderate conditions and used for tyrosinase immobilization. The support was pretreated with HCl (0.5¿N) solution and then sequentially immersed in ethylenediamine (EDA), glutaraldehyde solution (2% v/v) and the crude enzyme. In comparison with the untreated one, the immobilized enzyme on the EDA-treated support offered a 3.7-fold increase in activity. The FTIR spectra as well as EDX analysis proved the presence of amine groups in the cellulosic paper and also covalent immobilization of tyrosinase on the modified support. When considering the effect of pH on the activity at 25¿°C, a maximum relative activity of 134% at pH 6 was revealed. Similarly, evaluating the effect of temperature on the activity at pH 7 displayed a maximum relative activity of 152% at 35¿°C. The immobilized enzyme was suitable for use for more than four cycles to degrade a phenolic compound at severe pH and temperature conditions. Additionally, the immobilized enzyme was active after treatment of the surface at different pHs and temperatures for 105¿min. The chemically modified cellulosic paper can be used as a support for enzyme immobilization.

Supersonic gas-liquid separation is considered as one of the novel methods for natural gas conditioning that removes either water or heavy hydrocarbons from the natural gas without using chemical ingredients. The expansion of natural gas stream in a supersonic nozzle increases the fluid velocity to supersonic level and makes low pressure and temperature conditions in which nucleation of the liquid phase and condensation initiate. The process includes two isentropic processes with an intermediate shockwave. This research is the first serious attempt for controlling the supersonic separation units and applies the stability concept for actual conditions and disturbances in the gas pressure and composition during the lifecycle of a gas well. The article explores how the optimal performance of a supersonic nozzle can be saved with variations in the nozzle input gas pressure or composition. As the phase change and condensation are mainly occur at the shockwave position, the geometry configuration of supersonic nozzle is of high importance so that the drain location should be aligned with the shockwave location. An algorithm is employed to find a control function to compensate the backpressure of the nozzle within the feed pressure variation. It guarantees the equipment to be kept effectively in the optimal operating condition. In a case study, it is explained how the proposed solution enables the system to keep the dew point within ±2.5¿°C drift from the desired criteria following a ±18% disturbance in the inlet pressure. Moreover, investigation on the effect of natural gas composition shows that the separation system is intrinsically robust to variations in the main natural gas composition.

New experimental results are reported for the solubility of carbon dioxide (CO2) in nitrate- and thiocyanate-based ionic liquids (ILs) at temperatures ranging from 298.15 to 333.15 K and pressure up to 4.5 MPa. The studied ILs are 1-methyl 3-octylimidazolium thiocyanate [Omim][SCN], 1-methyl 3-hexylimidazolium thiocyanate [Hmim][SCN], 1-methyl 3-octylimidazolium nitrate [Omim][NO3], and 1-butyl 3-methylimidazolium tetrafluoroborate [Bmim][BF4]. The solubility measurements are performed in a known volume stainless steel equilibrium cell. The experimental data indicated the solubility of CO2 decreases with increasing of temperature. Henry's constant are calculated from the solubility data. The experimental results for CO2 solubility are correlated with the extended Henry's law and Pitzer virial expansion using binary parameters. The correlation results of gas solubility are agreed with the experimental data.

The focus of this paper is to study the liquid-liquid extraction process for the separation of toluene from alkane employing the ionic liquids N-butylpyridinium nitrate, [BPy][NO3], and N-hexylpyridinium nitrate, [HPy][NO3], as a new solvents. New experimental data for the ternary systems of {[BPy][NO3] (1)¿+¿heptane, or octane, or decane (2)¿+¿toluene (3)} and {[HPy][NO3] (1)¿+¿heptane, or octane, or decane (2)¿+¿toluene (3)} at T¿=¿298.15¿K and atmospheric pressure are reported. The Othmer-Tobias and Hand correlation are examined to check the reliability of the experimental LLE data. The toluene distribution ratios and selectivity were calculated form the experimental data. The selectivity values are higher than unity which indicates the ILs, [BPy][NO3] and [HPy][NO3], used in this work are potential solvents to separate toluene from alkane. Besides, the effect of the alkane chain length in the selectivity values was evaluated. In addition, the result of the NRTL thermodynamic modeling shows, the experimental data were satisfactorily correlated.

Graphene (G) and graphene oxide (GO) were functionalized with 1-methyl-3-octyl-imidazolium hexafluorophosphate ([Omim][PF6]), 1-methyl-3-octyl-imidazolium tetrafluoroborate, and 1-methyl-3-octyl-imidazolium thiocyanate ionic liquids through a non-covalent functionalizing procedure. Different characterization techniques including XRD, AFM, FTIR, SEM/EDX, TGA, XPS, and RAMAN spectroscopy were used to verify the success of functionalization. The functionalized graphenes and graphene oxides were then used as adsorbents to remove dibenzothiophene from a model fuel having decane as the solvent. Among the prepared adsorbents, the functionalized graphene with the ionic liquid of [Omim][PF6] exhibited the highest adsorption capacity of 6.5¿mg/g. The results showed that functionalization of graphene and graphene oxide improves their adsorption capacity in comparison to those of graphene (3.2¿mg/g) and graphene oxide (2.25¿mg/g).

Aqueous biphasic systems (ABS) present a powerful technique for the development of sustainable and biocompatible separation processes in biotechnology. Polyethylene glycols (PEGs) are the most common polymers used in the polymer-salt ABS. However, the hydrophilic nature of PEGs and the low polarity of the PEG-rich phase limit the applicability of this technique. To overcome this limitation, in recent years, a new approach has been proposed based on the use of ionic liquids (ILs) as adjuvants in PEG-based ABS. In this regard, this work is devoted to study the influence of IL 1-butyl-3-methylimidazolium bromide ([C4C1im]Br) as an adjuvant compound on the formation of {PEG (400, 600, 4000, and 6000) + tri-potassium phosphate (K3PO4)} ABS. For this purpose, phase diagrams of the {PEG (400, 600, 4000, and 6000) + K3PO4} ABS with the addition of small quantities of IL were determined at T = 298.15 K. The results obtained indicate that the binodal curves of the systems with and without IL are more deviated from each other with decreasing the PEG molecular weight, and the biphasic region of the systems with IL is larger than that of ternary systems for PEG 400 and 600; while, for PEG 4000 and 6000 is smaller. The partition coefficients of IL (KIL) within the studied ABS were also determined at T = 298.15 K. The KIL values were observed to decrease with increasing the PEG molecular weight. In addition, the experimental data are correlated using the NRTL model. The comparisons between the correlation and the experimental data reveal a good agreement.

The phase diagrams of the {1-butyl-3-methylimidazolium nitrate ([Bmim][NO3]) / 1-hexyl-3-methylimidazolium nitrate ([Hmim][NO3]) + dipotassium hydrogen phosphate (K2HPO4)}c aqueous biphasic systems (ABS) and the binodal curves of {1-octyl-3-methylimidazolium nitrate ([Omim][NO3]) + K2HPO4} ABS have been determined experimentally at T = (288.15, 298.15, and 308.15) K. The Merchuk equation with three dependent-temperature adjustable parameters was used for reproducing and predicting the binodal curves. The effect of the alkyl chain length of ionic liquids (ILs) was studied. It was found that the two-phase formation in the investigated ABS is decreased with decreasing the alkyl chain length of IL in the order: [Hmim][NO3] > [Omim][NO3] > [Bmim][NO3]. Moreover, the effect of temperature on the binodal curves and tie-lines was also discussed. It was shown that the biphasic region expanded with a decrease in temperature, whereas the absolute value of slope of the tie-lines slightly decreased with an increase in temperature. Finally, the liquid-liquid equilibrium (LLE) data for the studied systems are correlated by using the NRTL thermodynamic model, and good agreement was obtained between the correlation and the experimental data.

Antimicrobial and anti-adhesive properties of broad range of 1-Butyl-3-methylimidazolium ionic liquids (ILs) were investigated in our previous work. Since the biological properties of ILs have been one of the most highly debated topics and because of low information on the biological behavior of ILs, a supplementary study was performed to find antibacterial and anti-adhesive activity of many other important ILs. Therefore, imidazolium and pyridinium based ionic liquids including [HMIM][I], [HMIM][PF6], [HMIM][Cl], [HMIM][BF4], [HMIM][NTF2], [HMIM][PTS], [HDMIM][BF4], [HMIM][NO3], [HPY][NO3], [BPY][NO3], [OMIM][NO3] and [BMIM][NO3] were selected for this study. Antibacterial and anti-adhesive activities of these ILs were evaluated against a wide range of pathogenic bacteria namely Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli, Bacillus tequilensis and Bacillus subtilis. Agar disk diffusion, agar well diffusion and minimum inhibitory concentration (MIC) analyses as well as minimum bactericidal concentration (MBC) were used for determination of antimicrobial activity. Anti-adhesive activity was investigated by 96 well microtiter plate assay. All the ionic liquids showed antibacterial activity against mentioned microorganism. However, [OMIM][NO3] showed the strongest antibacterial activity because of its long alkyl chain length. Among 1-Hexyl-3-methylimidazolium based ILs, [HMIM][NO3] presented the best antibacterial activity. [HPY][NO3] was on the other hand the strongest growth inhibitor among pyridinium based ILs. In addition, the result of the anti-adhesive activity showed that although [HPY][NO3] exhibited the best anti-adhesive activity, not all ionic liquids have anti-adhesive activity.

In this work the desulfurization ability of two imidazolium based ionic liquids from n-decane, which is used as a model of fuel, has been developed. The systems of ternary liquid-liquid equilibria containing ionic liquid + n-decane + thiophene have been determined at three different temperatures. All systems have been shown the ability of ILs for removal of thiophene from n-decane. The selectivity and the solute distribution ratio were calculated for all systems. The data obtained have been correlated with non-random two liquid NRTL model. The phase equilibria diagrams for the ternary mixtures including the experimental and calculated tie-lines have been presented.

Four nitrate-based ionic liquids (ILs), i.e. 1-Butyl-3-methylimdazolium nitrate ([Bmim][NO3]), 1-Octyl-3-methylimdazolium nitrate ([Omim][NO3]), 1-Butylpyridinium nitrate ([BPy][NO3]), and 1-Octylpyridinium nitrate ([OPy][NO3]) were synthesized and used as extractant for the removal of dibenzothiophene (DBT) from the model oil. The effects of cation type, cation's alkyl chain length, extraction time, temperature, and IL/model oil volume ratio on the DBT removal were investigated. The ILs demonstrated high extraction performance with this order: [Omim][NO3] > [OPy][NO3] ¿[Bmim][NO3] > ([BPy][NO3]. The results suggested that [Omim][NO3] could be utilized as an appropriate solvent for the extractive desulfurization of fuel oil. It could reduce 94.8% of sulfur content in model oil from 500 to 26 ppm at 25 °C and IL/model oil volume ratio of 1:1 in a single-stage extraction. [Omim][NO3] could be reused six times without an impressive decrease in its activity.

New experimental data for the ternary systems of 1-butyl 3- methylimidazolium nitrate ([Bmim][NO3]) or 1-methyl 3-octylimidazolium nitrate ([Omim][NO3]) + alkane (hexane or heptane or octane) + aromatic (ethyl benzene or p-xylene) at 298.15 K and atmospheric pressure are reported. The aromatic selectivity and distribution coefficient are calculated from experimental data. The effect of alkyl chain length of ionic liquids as well as alkane on the aromatic selectivity is studied. The selectivity values for the studied systems with [Bmim][NO3] is more than [Omim][NO3]. The reliability of the experimental data is tested with the Othmer- Tobias and Hand equations. The NRTL thermodynamic model was successfully used to correlate the experimental data.

In this research, the liquid-liquid equilibrium data (LLE) for the ternary systems of N-butylpyridinium nitrate, [BPy][NO3] + heptane + benzene and N-hexylpyridinium nitrate, [HPy][NO3] + heptane + benzene at the temperatures (298.15, 308.15 and 318.15) K and atmospheric pressure were determined. The solute distribution ratio and selectivity from the LLE data were calculated. The benzene selectivity for systems with [BPy][NO3] is higher than [HPy][NO3] and [BPy][NO3] is an appropriate solvent for benzene extraction. Besides, the infiuence of the temperature on benzene distribution ratio and selectivity of benzene was also investigated. Finally, the experimental data were correlated with the NRTL thermodynamic model.

Ionic Liquids (IL's) are now considered as useful alternative solvent for the desulfurization of gasoline and diesel oils by liquid-liquid extraction. In this work, 1-hexyl-3-methylimidazolium thiocyanate([Hmim][SCN]) and 1-octyl-3-methylimidazolium thiocyanate([Omim][SCN]) as ionic liquids were investigated as model solvents for removal of thiophene from some aliphatic hydrocarbons (. n-hexane, n-octane and n-decane) as fuel model. Liquid-liquid phase equilibrium data were measured for ternary systems containing one ionic liquid as solvent, thiophene as sulfur component and one aliphatic hydrocarbon as fuel model at 298.15 K under ambient pressure. It was found that the IL with lower molecular weight of cation has higher selectivity but lower solute distribution coefficients. Besides, the experimental data demonstrates that the selectivity increases as alkane chain length of fuel model increases while the solubility of ionic liquids decreases, hence the costs of desulfurization process will be decreased. Our results show that for the case of [Hmim][SCN](1) + n-decane(2) + thiophene(3) the highest selectivity and lowest alkane solubility were obtained. In other words [Hmim][SCN] is a more suitable solvent than [Omim][SCN] for desulfurization of higher alkane. Finally in order to find the model parameters, the nonrandom two liquid (NRTL) was used to correlate the experimental data. The results show the model can successfully correlate the experimental data.

Phase diagrams of the (1-butyl-3-methylimidazolium nitrate ([Bmim][NO3])/1-hexyl-3-methylimidazolium nitrate ([Hmim][NO3]) + dipotassium carbonate (K2CO3)) aqueous biphasic systems (ABS) and the binodal curves of (1-octyl-3-methylimidazolium nitrate ([Omim][NO3]) + K2CO3) ABS were determined experimentally at different temperatures. The binodal data were correlated with the Merchuk equation. The effect of temperature and the alkyl chain length of ionic liquid (IL) on two phase formation were investigated. The experimental data reveals the biphasic region expands with reduction in temperature; however, the absolute value of slope of the tie-lines reduces with an increase in temperature. Moreover, the ability of the studied ILs to form two phase in the presence of K2CO3 salt are in the order of [Hmim][NO3] > [Omim][NO3] > [Bmim][NO3]. The experimental data are correlated with the NRTL model with a good accuracy.

A Brønsted acidic ionic liquid (IL), 1-octyl-3-methylimidazolium hydrogen sulfate ([Omim][HSO4]), was prepared and utilized as the extractant and catalyst to study the oxidative desulfurization of dibenzothiophene (DBT) in n-decane as the model oil. The effects of the alkyl chain length of the IL cation, temperature, H2O2/DBT molar ratio (O/S), IL/oil mass ratio, initial S-content, and sulfur species on the sulfur removal of the model oil were investigated. Complete removal of DBT was observed by [Omim][HSO4], O/S molar ratio of 5, and IL/oil mass ratio of 1:2 after 70 min at 25°C. The order of observed oxidizing reactivity for different sulfur species was as follows: DBT > benzothiophene (BT) > thiophene (TH) > 4,6-dimethyldibenzothiophene (4,6-DMDBT). The IL could be reused six times without a significant decrease in the desulfurization activity. The kinetics of oxidative desulfurization for DBT by [Omim][HSO4] was found to be pseudo-first-order with an apparent rate constant of 0.0734 min-1 (at 298 K) and the apparent activation energy of 24.51 kJ/mol. The ultrasound-assisted oxidative desulfurization (UAOD) process was also applied and represented a high desulfurization performance for the model oil in a fast reaction. The effects of various parameters, including irradiation time, settling time, O/S molar ratio, and IL/model oil mass ratio, on the UAOD process were studied. The complete sulfur removal efficiency could be reached after 3 min of ultrasonic irradiation with an ultrasonic power of 30 W, ultrasonic frequency of 20 kHz, O/S molar ratio of 5, and IL/oil mass ratio of 1:2. It was observed that the application of ultrasonic irradiation allows the desulfurization process to be performed in a shorter time. The sulfur removal of real diesel was 77.2% in the ODS process, and 76.3% in the UAOD process under the optimal conditions.

One of the novel technologies for natural gas dehydration and natural gas dew-point conditioning is supersonic separation, which has remarkable features, including compact and maintenance-free design. Due to its complex design and the difficulty of experimental analysis, researchers tend to conduct numerical modeling for behavior investigation of the nozzle focusing on shockwave which is the main phenomena inside the nozzle. The present NN-model outperforms a selection of data and proposes an efficient NN-based algorithm for shockwave position estimation as the key nozzle geometry parameter. Data for the shockwave location was collected from a wide range of results from the literature and then a neural network based self-organizing map was adapted to the dataset. This created a classified dataset and the use of unreal weight and repeated experimental results from different research were avoided. A neural network was employed for modeling the shockwave location through the nozzle using a better quality dataset. Additionally, the one-dimensional inviscid theory was utilized in the recursive approach for comparison to the main proposed model. Simulation results presented in this research reveal the effectiveness of the proposed neural network technique for supersonic nozzle modeling and make it possible to determine the shockwave location from the nozzle pressure boundary conditions. The results showed that the supersonic nozzle separation have capability to be used in both low-pressure applications and high pressure ones. The dimensionless length for shockwave location is predicted in the range of 0.82¿0.92 for the former and 0.72 to 0.95 for the later, depending on pressure recovery ratio.