Biosorption of chromium ions by using black tea leaves waste and the effect of some parameters on the removal of ions

Abstract

Biosorption can be an effective technique for the treatment of heavy metals bearing waste water resulting from human and industrial activities. several bioadsorbents have the ability to remove the heavy metals and thereby making water contaminant free. In the present study the biosorption of heavy metals using the black tea leaves waste and parameters affecting the biosorption of Cr ion; such as contact time, pH, temperature, dosage and particles size have been investigated. The present study showed that the contact time taken for maximum sorption of Cr ion was 120 min. The maximum percent removal of Cr ions on adsorbent was observed at pH 6 and significantly decreased by reducing the pH values and slightly decreased at higher pH values. The results indicated that the increasing of temperature from 35°C  to 50°C induced that the adsorption capacity of Cr ions with highest adsorption capacity at  45°C and the concentration of 2 g was sufficient for maximum biosorption. It was obvious that the adsorption capacity of metal ion on tea waste increased by decreasing the particle size and the best particles size was 200 μm. The experiment results showed that maximum removal of Chromium ion by tea waste is 89.5 % at optimum condition.