Cadmium and zinc biosorption by Macrocystis pyrifera: changes in the biomass

PLAZA CAZÓN JOSEFINA; GUIBAL ERIC; TAULEMESSE JEAN MARIE; VIERA MARISA; DONATI EDGARDO

Simposio; 18th International Biohydrometallurgy Symposium; 2009

Abstract. Macrocystis pyrifera was used for the recovery of Zn2+ and Cd2+ from slightly acidic solutions. In single-component solutions containing concentrations between 30 and 400 mg L-1. For bi-component solutions two different approximations were used: zinc and cadmium concentrations were simultaneously varied or one metal concentration was fixed at different concentrations of the other. For the study of metal desorption, EDTA, HNO3 and Ca(NO3)2 were used as eluents. Metal release (Ca2+, Mg2+, K+ and Na+) was monitored in order to evaluate ion exchange mechanisms. After metal sorption/desorption steps the sorbent was characterized using SEM-EDAX analysis. SEM-EDAX analysis also allowed identifying the presence of elements such as Si, Al, Co, Ag, S, P, and Fe in the cell wall. Zinc desorption was almost complete when using 0.1 M nitric acid solution and the sorbent was not significantly damaged by the acidic treatment. Cadmium was completely removed from loaded sorbent when using EDTA, but at the expense of a partial degradation of the biomass as evidenced by the decrease in the intensity of the C and O peaks (SEM-EDAX).