BIOSORPTION OF CHROMIUM FROM TANNERY WASTEWATERS BY CHITOSAN OBTAINED FROM EXOSKELETON SHRIMP

Abstract

Chromium in the effluent is a major concern for tanning industry. Chemical precipitation methods are commonly employed for the removal of chromium but this leads to formation of chrome-bearing solid waste. Ion exchange and membrane separation methods are relatively expensive. In this study a chitosan bioadsorbent has been employed to remove chromium from tannery effluent. The effect of pH and chromium concentration showed chitosan to exhibit uptake of about 52 mg Cr (III)/g at optimum pH of 4.0. Langmuir and Freundlich models were applied. Increase of initial concentration of Cr resulted to a decrease in adsorption efficiency.