Modified sugarcane bagasse as effective biosorbent for copper ions removal

Abstract

In this study, sugarcane bagasse (SCB) as a cheap and effective biosorbent was used for copper ions (Cu(II)) removal and modification was performed on SCB with HCl chemical washing and mercerization with strong NaOH in order to improve the removal capability of Cu(II) from aqueous solution. The effects of three influencing parameters including pH, temperature and initial metal ion concentration on Cu(II) adsorption were investigated for both untreated and modified SCB samples (U-SCB, HCl-SCB and M-SCB). The maximum removal efficiency obtained in the experiments was 98.75% for HCl-SCB while M-SCB was 93.1% at pH 5 with an initial metal ion concentration of 10 mg L−1. Four isotherm models including Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm were used to describe the adsorption process of Cu(II) ions for each SCB sample. Among these four isotherms, the experimental data was best fitted to Langmuir isotherm with R2 above 0.95. Based on the Langmuir isotherm, the maximum monolayer adsorption capacity was 0.523, 2.006 and 0.938 for U-SCB, HCl-SCB and M-SCB. It was concluded that the modification performed on SCB with HCl was able to improve the removal efficiency of Cu(II) from 71.6% up to 98.75%.