Biosorption of heavy metals by paper mill waste from aqueous solution

In the present study the removal of lead, cadmium, nickel and copper from aqueous solution was carried out using paper mill sludge. Time course studies were carried out with these metals and effect of pH (4–9), metal concentration (5–100 mgl¹), biomass concentration (1–5%) were evaluated in batch sorption system. Optimum results obtained at pH 4.5 with 1% biomass concentration (w/v), biosorption was rapid, more than 70% of metal ion adsorbed within 15 minutes even at a concentration of 100 mgl¹ of metal. Langmuir and Freundlich sorption isotherm were overall applicable and showed that physicochemical adsorption and ion exchange interactions simultaneously play a role in binding of the metals. The significance of this paper is the utilization of low cost sorbent available in abundance for the removal of metals from dilute aqueous solution.