A COMPARATIVE-STUDY OF COPPER(II) BIOSORPTION ON CA-ALGINATE, AGAROSEAND IMMOBILIZED CHLORRELA-VULGARIS IN A PACKED-BED COLUMN

Little attention has been paid to investigating the effect of operatin g variables on the metal-ion sorption characteristics of agarose and a garose-micro-organism systems in a fixed bed, although some fragmentar y studies related to Ca-alginate and Ca-alginate-micro-organism system s have been reported in the literature. In this study a comparative bi osorption of copper(II) ions to Ca-alginate, agarose biopolymers and i mmobilized C, vulgaris, a green alga, was investigated in a packed-bed column operated in continuous mode, as a function of the flow rate an d inlet metal-ion concentration. The quantities of Cu(II) ions removed relative to the effluent volumes were determined by evaluating the br eakthrough curves obtained at different flow rates and different inlet Cu(II) concentrations. The data confirmed that early saturation and l ower Cu(II) removal was observed at higher flow rates and higher Cu(II ) concentrations for all packing materials. Ca-alginate is a good adso rbent of Cu(II) ions and immobilization of C. vulgaris to Ca-alginate only marginally increased the biosorption yield. However, agarose-immo bilized C. vulgaris clearly increased the biosorption capacity. Agaros e and agarose-algae systems showed a rapid Cu(II) uptake initially whi le Cu(II) ion adsorption to Ca-alginate and Ca-alginate-algae systems was limited initially by the diffusion of the solute through the pores . Total Cu(II) removal by Ca-alginate and immobilized C. vulgaris was higher than that of agarose and agarose-C. vulgaris systems over longe r time periods. (C) 1998 Elsevier Science Ltd. All rights reserved.