Statistical optimization and kinetic studies on removal of Zn2+ using functionalized carbon nanotubes and magnetic biochar

A comparative study on the adsorption capacity of functionalized carbon nanotubes (CNTs) and magnetic biochar for the removal of Zn2+ was investigated. Statistical analysis revealed that the optimum conditions for the highest removal of Zn2+ are at pH 10, dosage 0.09 g, agitation speed and time of 120 rpm and 120 min respectively. The removal efficiency of Zn2+ for an initial concentration of 1.1 mg/L using functionalized CNT was 99% and using magnetic biochar was 75%. The maximum adsorption capacities of 1.05 and 1.18 mg/g for functionalized CNT and magnetic biochar respectively. The adsorption isotherms are well described by both Langmuir and Freundlich models and adsorption kinetic obeyed pseudo-second order. (C) 2013 Elsevier Ltd All rights reserved.