A comparative study for the biosorption characteristics of chromium(VI) on Ca-alginate, agarose and immobilized C-vulgaris in a continuous packed bed column

A comparative biosorption of chromium(VI) ions to Ca-alginate and agarose biopolymers and immobilized C. vulgaris, a green alga was investigated. The experiments were carried out in a packed bed column operated in a continuous mode, as a function of the flow rate and inlet chromium(VI) ion concentration. The removal percentage of chromium(VI) ions related to the effluent volumes were also determined. Agarose and agarose - algae systems showed a rapid chromium(VI) uptake initially while chromium (VI) ion adsorption to Ca-alginate and Ca-alginate-algae systems was limited initially by the diffusion of the solute through the pores. Ca-alginate was not a good biosorbent for chromium(VI) ions and immobilization of C. vulgaris to Ca-alginate only marginally increased the biosorption yield. However, agarose and agarose immobilized C. vulgaris increased the biosorption capacity. Total chromium(Vn) removal by agarose and agarose-C. vulgaris systems were higher than that of Ca-alginate and Ca-alginate immobilized C. vulgaris at the same time interval.