Biosorption experiments

Biosorption experiments were carried out in 50 ml conical flasks. Initial Cr(VI) concentration of 10 mg/L was used in order to determine the optimum pH, contact time, biomass concentration and temperature. The Cr(VI) biosorption on Eupatorium adenophorum-alginate beads was performed with varying initial pH values from 1.0 to 7.0, biomass concentration from 1.0 to 7.0, contact time from 0 to 130 min, and temperature from 20 to 40°C respectively. Equilibrium isotherm experiments were carried out with initial Cr(VI) concentration between 10 and 300 mg/L at pH 2.0, biomass concentration 1.0 g/L and contact time 60 min respectively. All experiments were performed in triplicate and the mean values were used in the data analysis. The Cr(VI) concentration was determined at 540 nm followed by complex formation with 1,5-diphenylcarbazide (Merck, Germany) using a spectrophotometer (Shimadzu, Japan) [28].