Removal of heavy metal ions using nano-cellulose prepared from rice husk: validation by differential pulse voltammetry

Abstract

In this work, Cellulose was extracted from rice husk and chemically modified to produce Nano-Cellulose. It was characterized by FTIR, XRD, SEM/EDS, TEM, BET surface area analyzer, Particle size analyzer and tested for the removal of metal ions i.e. Zn(II), Cd(II), As(III), Pb(II) and Sn(II) from aqueous solution. The removal method was validated by differential pulse voltammetry (DPV). An adsorption experiment was performed to investigate the effects of initial pH, adsorbent dose, contact time and initial concentration of heavy metal ions on the adsorption capacity of nanocellulose. The experimental results revealed that the removal of metal ions on the nanocellulose was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 5–6. An adsorbent dose of 8mg/mL was sufficient for effective adsorption. In addition, the kinetics and equilibrium data are well described by pseudo-second-order kinetics and the Freundlich adsorption isotherm model at 50 min contact time and 50 mg/L initial concentration. Moreover, the desorption and re-adsorption performance was also studied, and the results revealed that the Nano-cellulose still showed good adsorption performance up to eight cycles of regeneration.