Actual Adsorptive Efficiency of Aqueous Cr(VI) Using Modified Banana Pseudostems

Abstract

A wide application of chromium (Cr) in industries has discharged large quantity of Cr(VI) into the environment. Cr(VI) is a strong oxidizing agent that can react rapidly to produce toxic compounds to humans. Various agricultural products and byproducts have been studied for the sorptive removal of Cr(VI). However, less attention has been given to the presence of Cr(III) in solution after the adsorption with significant effect to actual adsorption capacity of the material. Here the Cr(VI) removal efficiency was investigated by using modified banana pseudostems (m-BP). Banana pseudostems were treated with 0.08 M HCl for 4 h and washed thoroughly. The maximum adsorption capacity of Cr(VI) was found at pH 2, adsorbent dose 34 g/L, contact time of 180 min and 100 mg/L initial Cr(VI) concentration. The adsorption efficiency of Cr(VI) onto m-BP was recorded to be 73.6% while the total conversion of Cr(VI) was 99.6%. The adsorption efficiency was lower than the total conversion of Cr(VI) due to the reduction of Cr(VI) to Cr(III) by the presence of organic groups in banana pseudostems. Owing to relatively high efficiency, m-BP can be used as effective and very low cost adsorbent for Cr(VI) removal from wastewater.