Biosorption of malachite green, a cationic dye onto Pithophora sp., a fresh water algae

Batch sorption experiments were carried out for the removal of malachite green from its aqueous solution using Pithophora sp., a fresh water algae as biosorbent. Dye uptake was found to increase with contact time and initial malachite green concentration. Equilibrium uptake was found to be pH dependent and maximum uptake was observed at a pH of 6. The effect of algae concentration on equilibrium uptake was also estimated. The equilibrium data tend to fit Freundlich isotherm equation. Kinetic studies showed that the biosorption process follows first order rate kinetics with an average rate constant of 0.9213 min−1. The study confirms that the fresh water algae can be used as biosorbent for the removal of malachite green from its aqueous solution. The biosorption process was found to be surface diffusion controlled with an effective diffusion coefficient of 0.011361 cm2/s.