Cu2+ Removal and recovery by Spi SORB: batch stirred and up-flow packed bed columnar reactor systems

Abstract

The biosorption of Cu2+ by free and poly acrylamide gel (PAG) immobilized Spirulina platensis (SpiSORB) was characterized under batch and continuous packed bed columnar reaction systems. The biosorption of Cu2+ was shown to be highest at pH of 6.0 for both types of biomass. The PAG immobilization process did not interfere with the Cu2+ binding sites present on biomass leading to cent percent (ca. 250 mg g−1 of dry biomass) retention of biosorption as compared to free cells. Transmission electron microscopy on Cu2+ localization revealed that majority of metal is being sequestered by the cell wall only. The infrared spectrum of metal treated S. platensis biomass indicated the possible involvement of amide, amino, and carboxyl groups in metal binding. Up-flow packed bed columnar reactor containing 2.0 g of PAG immobilized S. platensis shown a maximum of 143-fold volume reduction factor at the residence time of 4.6 min for Cu2+ alone and found to decrease dramatically when Zn2+ is present in a bimetallic solution.