Single, binary and ternary metal adsorption using acid‐treated Aegle marmelos Correa shell: kinetic, mechanistic and thermodynamic study

Abstract

ABSTRACTIn this study, adsorption of metals from aqueous solution using H2SO4‐treated Aegle marmelos Correa shell (AMCS) was carried out in single and multimetal system. The maximum BET surface area (34.28 m2/g) and conspicuous change in the adsorbent surface were achieved when absolute concentration (98%) of acid was used to activate the AMCS. The sorption capacity of Pb2+, Ni2+ and Sr2+ was increased from 21.48 to 81.6 mg/g, 6.37 to 52.89 mg/g and 19.57 to 69.95 mg/g, respectively, as the H2SO4 concentration increased from 24.5% to 98% to activate the AMCS. The maximum adsorption capacities of Pb2+, Ni2+ and Sr2+ were observed at pH 5.2 (82.9 mg/g), 5.8 (54.89 mg/g) and 6.8 (72.95 mg/g), respectively. Presence of other ions significantly reduces the metal uptake when they were present at high concentrations in the metal solution. The equilibrium data fitted satisfactorily with Langmuir model compared with other models. Monolayer sorption capacity was obtained as 122.7, 70.18 and 80.73 mg/g for Pb2+, Ni2+ and Sr2+ at 30 °C, respectively. The effect of binary and ternary metal ions on adsorption capacity was found to be antagonistic behavior. The sorption kinetics was found to follow the pseudo‐second‐order kinetic model. But, the positive values of ΔH° and the increase in metal uptake with increase in solution temperature indicate the endothermic reaction for Ni2+ adsorption. The intermolecular binding (ion–dipole) of Pb2+ and Sr2+ and intermolecular binding coupled with intramolecular binding of Ni2+ were responsible for metal binding with cellulosic and lignin function groups. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.