Adsorption of As(V) from contaminated water over chitosan coated magnetite nanoparticle: Equilibrium and kinetics study

Abstract

The efficacy of chitosan/magnetite nanocomposite (CTN) for remediation of arsenate ions [As(V)] from water was investigated. The prepared material could efficiently perform several cyclic runs with high As(V) removal efficiency and has the advantages over many established method. Different characterization techniques were performed to investigate the binding and structural properties of prepared materials. The study also focused on the effect of competing ions viz. phosphate and chloride on removal efficiency. The initial As(V) concentration (0.6mg/L) was found to decrease to less than 0.01mg/L at a contact time of 120min with an adsorbent dose of 1g/L. Increase in initial ion concentration of arsenate ions decreased the sorption rate, but the ion uptake capacity was increased. The sorption was reasonably explained with Langmuir (RL∼0.9851) and Freundlich isotherm models (n∼1.78). At low concentrations Langmuir monolayer sorption was followed but heterogeneity appeared at higher arsenate concentrations. The maximum adsorption capacity (Qo) calculated from Langmuir isotherm was found to be 10.81mg As(V)/g at room temperature and neutral pH. The sorption process was found to be governed by pseudo second order kinetics.