lit the present investigation, a fresh water green algae spirogyra spp. was used as an inexpensive and efficient biosorbent for Cr(III) removal from aqueous solution. The algal biomass was treated with 0. 1 M NaOH, 0.2 M CaCl2 and 5% HCHO. The biosorption efficiency was compared with untreated biomass. The effects of various physico-chemical parameters were studied, e.g. pH 3.0-6.0, initial metal ions concentration 20-150 mg L-1, algal dose 1.0-3.0 g L-1, and contact time 15-180 min, respectively. Biosorption of Cr(III) is highly pH dependent. Maximum 81.02% adsorption of Cr(III) was observed with 0.2 M CaCl(2)treated biomass at pH 5.0. Removal of Cr(III) was more than 70% in 45 min of contact time with different treated and untreated algal biomass at concentration 30 mg L-1. Maximum metal uptake (Q a,) was observed as 30.21 mg g(-1) with 0.2 M CaCl2 treated algal biomass indicate good biosorbents than other treated and untreated biomass. The high values of correlation coefficient (r(2) < 0.90) indicate equilibrium data of treated and untreated form of algal biomass well fitted in Freundlich than Langmuir isotherms model equations. (c) 2006 Published by Elsevier B.V.