Ecology, Environment and Conservation Paper

REMOVAL OF CR (III) BY BIOSORPTION ONTO POWDERED WASTE SLUDGE (PWS): EFFECTS OF OPERATING CONDITIONS

Ahmad Ashfaq

Abstract

The removal of heavy and toxic metal cation , Cr(III) from aqueous solution was investigated at pilot scale using counter-current contact mode. The effects of media conditions (pH of the solution, contact time, biomass concentration and initial metal concentration) on the biosorption of Cr(III) ions onto dried activated sludge were evaluated in a batch reactor. Initial metal concentrations varied from 10- 100 mg/L. The optimum biosorption conditions for pH, temperature and biomass concentration has been found at 5.0, 25oC and 1.0 mg/L respectively. The equilibrium data fitted well to the Langmuir isotherm model. The experimental data fitted well to the second order kinetic model. The maximum biosrption capacity was obtained as 55.40 mg/g of the biosorbent applied. The results also indicated that with an increase in the initial metal concentration the biosorption capacity also increased but removal efficiency decreased at the same time.