BIOREMEDIATION OF ARSENIC (III) AND CHROMIUM (VI) FROM AQUEOUS SOLUTIONS BY LIVING CELLS OF PSEUDOMONAS PUTIDA MTCC 3604: EQUILIBRIUM, KINETIC AND THERMODYNAMIC STUDIES

Abstract

The present research is to investigate the bioremediation of arsenic (III) and chromium (VI) from aqueous solutions by living cells of Pseudomonas putida (MTCC 3604) biomass. The various batch parameters affecting the treatment process like biosorbent dose, pH, initial concentration, contact time and temperature are investigated. The maximum removal capacity of Pseudomonas putida for arsenic (III) and chromium (VI) was found to be 45.04 mg/g and 52.94 mg/g, respectively, at optimum conditions of pH 5.5, contact time of 1 hr, biomass dosage of 4 g/L, and temperature of 25˚C. Biosorption data are fitted to linearly transformed Langmuir isotherm of arsenic (III) and chromium (VI) better than other isotherms with the correlation coefficient (R2> 0.99). Pseudomonas putida cell surface was characterized using SEMEDX and FTIR. The arsenic (III) and chromium (VI) ions were desorbed from Pseudomonas putida using both 1M HCl and 1M HNO3. The recovery for arsenic (III) and chromium (VI) ions was found to be higher than 88%. The pseudo-secondorder equation described is the best kinetic rate-controlling-step than other model with the correlation coefficient (R2> 0.99). Thermodynamic parameters are also calculated to study the effect of temperature on the removal process. The result reveals the exothermic, spontaneous, and feasible nature of removal process of arsenic (III) and chromium (VI) onto the living biomass of Pseudomonas putida.