A novel biosorbent from Azolla filiculoides was used in fixed-bed sorption columns and allowed quantitative determination of the characteristic process parameters which could then be used for performance comparison and process design. An zinc sorption capacity of 31.3mg/g predicted at a flow rate 480ml/h and pH 6.2, closely corresponded to the value observed. Lowering the influent pH to 4, the influent Zn2+ concentration to 50mg/l and increasing the flow rate to 800ml/h (residence time : 2.6 min), resulted in decreased sorption capacities by 15.3, 7.7 and 9.6%, respectively.