title: Adsorptive performance of un-calcined sodium exchanged and acid modified montmorillonite for Ni2+ removal: equilibrium, kinetics, thermodynamics and regeneration studies.
abstract: The efficacy of un-calcined sodium exchanged (Na-MMT) and acid modified montmorillonite (A-MMT) has been investigated for adsorptive removal of Ni(2+) from aqueous solution. Physico-chemical parameters such as pH, initial Ni(2+) concentration, and equilibrium contact time were studied in a series of batch adsorption experiments. The equilibrium time of contact for both adsorbents was about 230 min. The Redlich-Peterson model best described the equilibrium sorption of Ni(2+) onto Na-MMT and the Dubinin-Radushkevich model was the best model in predicting the equilibrium sorption of Ni(2+) onto A-MMT. The kinetics of Ni(2+) uptake by Na-MMT and A-MMT followed the pseudo second-order chemisorption mechanism. Sorptions of Ni(2+) onto Na-MMT and A-MMT were spontaneous and endothermic. Regeneration was tried for several cycles with a view to recover the adsorbed Ni(2+) and also to restore Na-MMT and A-MMT to their original states. The un-calcined Na-MMT and A-MMT have adsorptive potentials for removal of Ni(2+) from aqueous bodies.
authors.affiliation: Department of Environmental Science and Engineering, Ewha Womans University, Daehyundong 11-1, Seodaemungu, Seoul 120-750, Republic of Korea.
authors.forename: Christianah Olakitan
authors.initials: CO
authors.lastname: Ijagbemi
authors.forename: Mi-Hwa
authors.initials: MH
authors.lastname: Baek
authors.forename: Dong-Su
authors.initials: DS
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D007700:Kinetics; D009532:Nickel / Q000302:isolation & purification*; D012964:Sodium / Q000737:chemistry*; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D001546:Bentonite; D009532:Nickel; D012964:Sodium