naa a22 4500 510750222 CHVBK 20180411083101.0 cr unu---uuuuu 180411e20131201xx s 000 0 eng 10.1007/s11270-013-1704-0 doi (NATIONALLICENCE)springer-10.1007/s11270-013-1704-0 Simultaneous Adsorption of Tri- and Hexavalent Chromium by Organoclay Mixtures [Elektronische Daten] [Binoy Sarkar, Ravi Naidu, Mallavarapu Megharaj] Organoclays possess unique adsorption behaviour towards hydrophobic organic contaminants. They can also remediate ionic contaminants such as heavy metals and metalloids. The objective of the present study was to prepare organoclay and organoclay mixtures efficient to adsorb both cationic and anionic contaminants. The adsorbents were characterised by X-ray diffraction and infrared spectroscopy. Trivalent (Cr3+) and hexavalent (Cr2O7 2−) chromium were selected as the model contaminants representing cationic and anionic properties. Bentonite modified with cationic surfactant hexadecyl trimethylammonium bromide at double the cation exchange capacity of the clay remarkably improved Cr2O7 2− adsorption capacity (as high as 0.49mmolg−1). Similarly, its modification with anionic surfactant sodium dodecyl sulphate at the same dosage improved Cr3+ adsorption (as high as 0.36mmolg−1). When these two organoclays were physically mixed in equal proportions (1:1), the resultant organoclay mixture efficiently adsorbed both Cr3+ (as high as 0.21mmolg−1) and Cr2O7 2− (as high as 0.32mmolg−1) implying that the mixture could remediate both anionic and cationic contaminants simultaneously. The adsorption of Cr3+ by the organoclay and organoclay mixture fitted well to the Langmuir isothermal model whereas the adsorption of Cr2O7 2− fitted well to the Freundlich model. Springer Science+Business Media Dordrecht, 2013 Organoclay nationallicence Organoclay mixture nationallicence Heavy metals and metalloids nationallicence Adsorption nationallicence Tri- and hexavalent chromium nationallicence Sarkar Binoy CERAR-Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, 5095, Mawson Lakes, SA, Australia aut Naidu Ravi CERAR-Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, 5095, Mawson Lakes, SA, Australia aut Megharaj Mallavarapu CERAR-Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, 5095, Mawson Lakes, SA, Australia aut Water, Air, & Soil Pollution Springer Netherlands 224/12(2013-12-01), 1-10 0049-6979 224:12<1 2013 224 11270 https://doi.org/10.1007/s11270-013-1704-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11270-013-1704-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sarkar Binoy CERAR-Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, 5095, Mawson Lakes, SA, Australia aut NATIONALLICENCE 700 1- Naidu Ravi CERAR-Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, 5095, Mawson Lakes, SA, Australia aut NATIONALLICENCE 700 1- Megharaj Mallavarapu CERAR-Centre for Environmental Risk Assessment and Remediation, University of South Australia, Building X, 5095, Mawson Lakes, SA, Australia aut NATIONALLICENCE 773 0- Water, Air, & Soil Pollution Springer Netherlands 224/12(2013-12-01), 1-10 0049-6979 224:12<1 2013 224 11270 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer