Biosorption of lead(II) and copper(II) from aqueous solutions by pre-treated biomass of Australian marine algae

Chemically modified biomass of marine algae can effectively remove heavy me tals from waste water. Australian marine algae (Durvillaea potatorum and Ec klonia radiata) based biosorbents (DP95Ca and ER95Ca) were developed and st udied for their heavy metal removal properties from aqueous solutions. A tw o stage modification process substantially improved the leaching characteri stics of the biomass. Batch equilibrium experiments showed that the maximum adsorption capacities of DP95Ca for lead and copper were 1.6 and 1.3 mmol/ g, respectively. The corresponding values for ER95Ca were 1.3 and 1.1 mmol/ g. These capacities are comparable with those of commercial ion exchange re sins and are much higher than those of natural zeolites and powdered activa ted carbon. The heavy metal uptake process was found to be rapid with 90% o f the adsorption completed in about 10 min in batch conditions. Heavy metal adsorption was observed at pH values as low as 2.0 and maximum adsorption was obtained approximately at a pH of 4.5. Both biosorbents were effective in removing lead and copper in the presence of chelating agents and other l ight metal ions in waste water. (C) 1999 Elsevier Science Ltd. All rights r eserved.