2021 |
Khodabakhshloo N, Biswas B, Moore F, Du J, Naidu R, 'Organically functionalized bentonite for the removal of perfluorooctane sulfonate, phenanthrene and copper mixtures from wastewater', Applied Clay Science, 200 (2021)
© 2020 Elsevier B.V. The co-occurrence of a wide range of hydrophobic and hydrophilic contaminants with contrasting physicochemical properties in wastewaters makes practical remed... [more]
© 2020 Elsevier B.V. The co-occurrence of a wide range of hydrophobic and hydrophilic contaminants with contrasting physicochemical properties in wastewaters makes practical remediation a challenge. Applications of ion exchangers such as clays are an environmentally friendly option in a cleanup strategy. However, clays often require chemical functionalization to adsorb non-polar contaminants. In this study, the most readily available low-cost Iranian bentonite was modified with Arquad® 2HT-75 (IBA) and further tailored with palmitic acid (IBAP) in order to prepare effective adsorbents. They were used for the removal of perfluorooctane sulfonate (PFOS), phenanthrene (PHE) and copper ions (Cu2+) both in single (S) and binary (B) contaminant conditions in simulated and real wastewater. The IB showed a large affinity for Cu2+ in both single (qmax: 43.43 mg/L) and binary (qmax: 43.95 mg/L) systems. Adsorption of PFOS and PHE was dramatically enhanced by the functionalized clays IBA (KF (PFOS): 11.1 and KF (PHE): 9.65 mg (1-n) Ln g-1) and IBAP (KF (PFOS): 10.2 and KF (PHE): 16.68 mg (1-n) Ln g-1). The co-occurrence of PFOS or PHE with Cu2+ enhanced their adsorption onto clays indicating that Cu2+ can form bridges between clays and PFOS or PHE in different mechanism to increase adsorption of PFOS or PHE in binary solutions. The surface-tailored organoclay IBAP showed great potential for the complete removal of PFOS, PHE and 86.6% of Cu2+ from real wastewater, which is usually considered challenging.
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2020 |
Hassan M, Liu Y, Naidu R, Du J, Qi F, 'Adsorption of Perfluorooctane sulfonate (PFOS) onto metal oxides modified biochar', Environmental Technology and Innovation, 19 (2020) [C1]
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2020 |
Zhang T, Dong L, Du J, Qian C, Wang Y, 'Cuo and ceo2 assisted fe2o3 attapulgite catalyst for heterogeneous fenton-like oxidation of methylene blue', RSC Advances, 10 23431-23439 (2020) [C1]
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2020 |
Zheng L, Gao Y, Du J, Zhang W, Huang Y, Wang L, et al., 'A novel, recyclable magnetic biochar modified by chitosan-EDTA for the effective removal of Pb(ii) from aqueous solution', RSC ADVANCES, 10 40196-40205 (2020) [C1]
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2020 |
Hassan M, Naidu R, Du J, Liu Y, Qi F, 'Critical review of magnetic biosorbents: Their preparation, application, and regeneration for wastewater treatment', SCIENCE OF THE TOTAL ENVIRONMENT, 702 (2020) [C1]
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2020 |
Hassan M, Liu Y, Naidu R, Parikh SJ, Du J, Qi F, Willett IR, 'Influences of feedstock sources and pyrolysis temperature on the properties of biochar and functionality as adsorbents: A meta-analysis', Science of the Total Environment, 744 (2020) [C1]
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2019 |
Bekele DN, Du J, de Freitas LG, Mallavarapu M, Chadalavada S, Naidu R, 'Actively facilitated permeable reactive barrier for remediation of TCE from a low permeability aquifer: Field application', Journal of Hydrology, 572 592-602 (2019) [C1]
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2019 |
Liu Y, Du J, Dong Z, Rahman MM, Gao Y, Yan K, Naidu R, 'Bioavailability and risk estimation of heavy metal(loid)s in chromated copper arsenate treated timber after remediation for utilisation as garden materials.', Chemosphere, 216 757-765 (2019) [C1]
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2018 |
Gao YC, Guo SH, Wang JN, Zhang W, Chen GH, Wang H, et al., 'Novel Bacillus cereus strain from electrokinetically remediated saline soil towards the remediation of crude oil', Environmental Science and Pollution Research, 25 26351-26360 (2018) [C1]
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2017 |
Du J, Chadalavada S, Naidu R, 'Synthesis of porous bentonite organoclay granule and its adsorption of tributyltin', Applied Clay Science, 148 131-137 (2017) [C1]
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2016 |
Sun Z, He X, Du J, Gong W, 'Synergistic effect of photocatalysis and adsorption of nano-TiO2 self-assembled onto sulfanyl/activated carbon composite', ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH, 23 21733-21740 (2016) [C1]
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2016 |
Liu Y, Naidu R, Ming H, Dharmarajan R, Du J, 'Effects of thermal treatments on the characterisation and utilisation of red mud with sawdust additive', Waste Management and Research, 34 518-526 (2016) [C1]
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2015 |
Kuang Y, Du J, Zhou R, Chen Z, Megharaj M, Naidu R, 'Calcium alginate encapsulated Ni/Fe nanoparticles beads for simultaneous removal of Cu (II) and monochlorobenzene', Journal of Colloid and Interface Science, 447 85-91 (2015) [C1]
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2014 |
Jin X, Jiang M, Du J, Chen Z, 'Removal of Cr(VI) from aqueous solution by surfactant-modified kaolinite', JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, 20 3025-3032 (2014)
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2014 |
Du J, McLoughlin R, Smart RSC, 'Improving thickener bed density by ultrasonic treatment', International Journal of Mineral Processing, 133 91-96 (2014) [C1]
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2014 |
Shi L, Du J, Chen Z, Megharaj M, Naidu R, 'Functional kaolinite supported Fe/Ni nanoparticles for simultaneous catalytic remediation of mixed contaminants (lead and nitrate) from wastewater', Journal of Colloid and Interface Science, 428 302-307 (2014) [C1]
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2014 |
Du J, Chadalavada S, Chen Z, Naidu R, 'Environmental remediation techniques of tributyltin contamination in soil and water: A review', CHEMICAL ENGINEERING JOURNAL, 235 141-150 (2014)
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2010 |
Du J, Morris G, Pushkarova RA, St C Smart R, 'Effect of surface structure of kaolinite on aggregation, settling rate, and bed density', Langmuir, 26 13227-13235 (2010)
The flocculation and solid/liquid separation of four well-characterized kaolinites (2 well, 2 poorly crystallized) have been studied for comparison of surface structure (SEM), agg... [more]
The flocculation and solid/liquid separation of four well-characterized kaolinites (2 well, 2 poorly crystallized) have been studied for comparison of surface structure (SEM), aggregate structure during flocculation (cryo-SEM), settling rate, and bed density (with raking). It is shown that major differences in these properties are largely due to crystallinity and consequent surface structure of the extensive (larger dimension "basal") face. Well-crystallized kaolinites, with higher Hinckley indices and lower aspect ratios, have relatively smooth, flat basal surfaces and thicker edge planes promoting both effective initial bridging flocculation (largely edge-edge) and structural rearrangement to face-face during the raking process. This results in faster settling rates and more compact bed structures. Poorly crystallized kaolinites, with low Hinckley indices and high aspect ratios, exhibit ragged, stepped structures of the extensive face with a high proportion of nanosized islands forming cascade-like steps (i.e., multiple edges) contributing up to 30% of the specific surface area and providing flocculant adsorption sites (hydroxyl groups) across this extensive face. This leads to bridging flocculation taking place on both edge and extensive ("basal") planes, producing low-density edge-face structures during flocculation which leads to slow settling rates and poor bed densities. In particular, the complex surface morphology of the poorly crystallized kaolinites resists the transformation of edge-face structures to dense face-face structures under shear force introduced by raking. This results in low sediment density for poorly crystallized kaolinites. The studies suggest that the main influence on settling rates and bed densities of kaolinites in mineral tailings is likely to be related to the crystallinity and surface morphology of the kaolinite. They also suggest that interpretation of kaolinite behavior based on models of a flat (001) basal plane and edge sites only at the particle boundaries is not likely to be adequate for many real, less-crystallized kaolinites. © 2010 American Chemical Society.
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2009 |
Zbik MS, Du J, Pushkarova RA, Smart RSC, 'Observation of gaseous films at solid-liquid interfaces: Removal by ultrasonic action', Journal of Colloid and Interface Science, 336 616-623 (2009)
The critical role of dissolved gas nano-bubbles at solid surfaces in particle association, aggregation, adsorption and flotation has been recognised in the recent literature. The ... [more]
The critical role of dissolved gas nano-bubbles at solid surfaces in particle association, aggregation, adsorption and flotation has been recognised in the recent literature. The principles of mineral processing, fine particle separation, and water recovery depend upon changing the surface properties at the solid-liquid interface. It has been assumed that the solid surfaces are either in direct contact with the liquid or may have nano-bubbles attached only at hydrophobic surfaces. This paper shows that gaseous layers 50-100 nm thick can be attached surrounding high proportions of solid clay mineral surfaces restricting reagent access, producing buoyancy and aggregation. Ultrasonic treatment before flocculant addition effectively removes these gaseous layers as well as dispersed micro-bubbles. Re-aggregation after brief ultrasonication produces denser (less buoyant) flocs, demonstrated with cryo-SEM statistical analysis, giving more complete access of the flocculant to the aggregate surfaces. In the subsequent flocculant addition, the settling rates of the denser flocs can be increased up to 40%. If ultrasonic action is continued, the bridged flocs are disturbed with some redispersion of smaller flocs and individual platelets and consequent slower settling rates. © 2009 Elsevier Inc. All rights reserved.
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2009 |
Du J, Pushkarova RA, Smart RSC, 'A cryo-SEM study of aggregate and floc structure changes during clay settling and raking processes', International Journal of Mineral Processing, 93 66-72 (2009)
The destabilization of kaolinite suspension by anionic flocculant addition occurs in three zones; free settling, hindered settling and compression which usually includes a final b... [more]
The destabilization of kaolinite suspension by anionic flocculant addition occurs in three zones; free settling, hindered settling and compression which usually includes a final bed raking process in mineral processing practice. This paper reports changes in the kaolinite aggregate and floc structures in the different settling and raking zones by cryo-vitrification/cryo-SEM techniques with image analysis combining micro- and macro-flocs. Cryo-SEM images indicate that, even during free settling, fine clay particles are bridged predominantly in edge-edge (E-E) with some face-face (F-F) configurations forming single, small flocs and some chain structures. When these small flocs and chains settle into the hindered settling zone, the collision between flocs and chains results in "honeycomb" network structures formed with lateral chain-like extension. The settled bed consists of these honeycomb structures with both inter-aggregate and intra-aggregate trapped water and has relatively low bed density (e.g. < 12¿wt.% for a 2¿wt.% slurry). The effect of the raking process in dramatically improving thickener underflow solids has been extensively studied but the structural changes in flocs and aggregates in this process are less well defined. Raking the compression zone for 1¿h at 3¿rpm can release some of the trapped water in the "honeycomb" structure and the bed density for 2¿wt.% slurry improves dramatically to more than 36¿wt.%. Cryo-SEM illustrates the extensive restructuring of flocs from predominantly E-E to predominantly F-F in many areas. The STructural IMage ANalysis (STIMAN) software is used to combine a series of images at magnifications from 1000× to 8000×, including both macro- and micro-flocs. This structural analysis comparing the un-raked and raked bed samples gives increases in total particle area of 30% and in relative particle area of 6%. The relatively low energy rake action of the shear stress results in the disruption of the E-E chains and the honeycomb structure, partly releasing the trapped water and inducing some E-E to F-F aggregate restructuring are clearly illustrated in these results. © 2009 Elsevier B.V. All rights reserved.
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2006 |
Sun ZY, Du JH, Chen HS, Gong WQ, 'FTIR study of nano-iron oxyhydroxides' decoloration on the azo dye', Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, 26 1226-1229 (2006)
IR spectra were used to analyse the azo dye solution decoloration action by two kinds of iron oxyhydroxides. It was discovered that: (1) Acid Red G and methyl orange are apt to fo... [more]
IR spectra were used to analyse the azo dye solution decoloration action by two kinds of iron oxyhydroxides. It was discovered that: (1) Acid Red G and methyl orange are apt to form complex on the surface of iron oxyhydroxides > FeOH, especially Acid Red G. which possesses two -SO3 Na structures has a relatively high decoloration efficiency as a result of complexation reaction; (2) after 2 hours adsorption, the IR spectra of iron oxyhydroxides show characteristic wave numbers at 1033 and 1030 cm-1 which belong to -SO3Na, whereas the peaks at wave numbers between 1450 and 1400 cm-1, which belong to azo dye, disappear. These phenomena indicate that azo dye molecules are adsorbed on the surface of iron oxyhydroxides due to the negative -SO3Na structure, and at the moment when azo dye molecules are adsorbed on the surface of iron oxyhydroxides, the electron transfer occurs between the azo dye molecules and the iron oxyhydroxides surface's Fe3+ centre, which could lead to the rupture of azo bond. It can be infered that the decoloration of azo dye molecules is the co-effect of the selective chemical absorption and the oxidation-deoxidation effect on the surface of iron oxyhydroxides.
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