Adsorption isotherms, kinetics and thermodynamic studies towards understanding the interaction between a microbe immobilized polysaccharide matrix and lead

This work demonstrates the efficacy of a bacterium Halomonas BVR 1 strain (isolated from an electronic industry effluent) immobilized in sodium alginate primary host matrix for enhanced adsorption of lead. The immobilized microbe-polysaccharide combination leads to an increase in the number of metal binding groups and act as a secondary host, thereby aiding in an overall improvement of metal adsorption. The characterization of the immobilized adsorbent was done through FT-IR and SEM-EDAX techniques. The obtained results suggest a physicochemical interaction between the lead ion and the microbe immobilized sodium alginate beads. The effect of various analytical parameters on the adsorption of lead was studied in detail. Lead was quantitatively adsorbed in the pH range 8-10 in accordance with pseudo second order kinetics and Langmuir isotherm model. Thermodynamic parameters were calculated and the adsorption process was found to be spontaneous and exothermic. The over expression of proteins in the bacteria under metal stressed condition has also been depicted in this work. (c) 2014 Elsevier B.V. All rights reserved.