Biosorption of Heavy Metals by Dead Streptomyces fradiae

Abstract

Streptomyces fradiae dead biomass was found to adsorb different heavy metal ions. The biomass was crosslinked with glutaraldehyde for better mechanical stability. Batch sorption studies were carried out with Cu(II), Zn(II), Ni(II), and Pb(II) solutions (0.7 g/dm3) at 20°C, pH 5.5. Best biosorption was reached for copper ions (16 mg/g). Fixed-bed biosorption of Cu(II) ions was investigated varying bed height of the biosorbent, flow rate, and initial copper concentration of the solution. Breakthrough and saturation times increase with the increase of the bed height. The same parameters decrease with the increase in flow rate and initial copper concentration. Metal uptake (q0) and the Thomas rate constant (K) were calculated. Column sorption was a more effective process for copper removal (q0 = 17.32 mg/g), compared with the batch sorption values. Regeneration of the exhausted biosorbent was carried out using 0.1 N HCl eluant. Six cycles of adsorption and desorption were performed to study the reusability of the biosorbent.