Biosorption and desorption potential of gold(III) by freshwater microalgae scenedesmus obliquus as-6-1

Abstract

Biosorption is an eco-friendly and cost-effective way for recovering gold from high-volume and lowconcentration wastewater. In this study, the freshwater microalgae Scenedesmus obliquus AS-6-1 were used as biosorbent for gold(III) in short-term batch tests. For an initial gold(III) concentration of 5 mg/L, the optimum condition of gold(III) adsorption was 0.10 g/L biomass dosage, the temperatures in the range of 20 - 25 °C, pH 2.0 within 30 min. The level of Au (III) uptake by S. obliquus AS-6-1 could approach 15 % of the organism’s dry weight at the optimum conditions with an initial concentration of 20 mg/L. The gold-loaded biomass of S. obliquus AS-6-1 was able to be regenerated by 0.1 M thiourea at pH 2.0 and its desorption efficiency retained 95 %, 94 % and 88 %, respectively, in three alternating adsorption/desorption cycles. The current experiments suggest that the freshwater microalga S. obliquus AS-6-1 is a promising and efficient biosorbent for gold recovery.