Column studies of heavy metal biosorption by immobilized Spirulina platensis-maxima cells

The adsorption capacities of alginate, chitosan and immobilized Spirulina platensis-maxima cells were studied in a continuous packed-bed column, under dynamic condition. The composition of alginate and chitosan beads was optimized. Various operating conditions were applied; the effect of flow rate, column height and initial metal ion concentration were investigated. The alginate beads have the highest adsorption capacity for Cu(II), Cd(II) and Pb(II) ions, 3.4, 2.3 and 3.1 mmol g-1 per dry weight, respectively. The alginate-Spirulina system has slightly decreased adsorption capacity 3.1, 1.9 and 3 mmol g-1. The uptake of Cu (II), Cd(II) and Pb(II) by chitosan and chitosan-Spirulina beads is 0.8, 0.9, 0.7 and 1, 0.8, 0.6 mmol g-1. The Thomas and Yoon–Nelson models have been applied to analyse the breakthrough data. The results indicate feasible reuse of the beads at least in five sorption cycles.