The synergy of mercury biosorption through Brevundimonas sp. IITISM22: Kinetics, isotherm, and thermodynamic modeling

Abstract

This research experiment was conducted to investigate the potential of Brevundimonas species IITISM22 to remove mercury by using live biomass of bacterial cells at 298, 308, and 318 K. Characterization of bio-sorbent was done by FT-IR and SEM-EDX. The prime functional groups accountable for binding Hg were OH, -NH2, -CH, -SH and -COO. The deformed bacterial structure was seen after Hg adsorption over the bacterial cell. Influences of different experimental factors, such as pH, temperature, contact time, Hg concentration, and biomass dose was examined. IITISM22 exhibited the highest Hg absorption at pH 6.5, contact time of 4 h, and showed an increased adsorption capacity while increasing the concentration of Hg. Kinetics were recommended by pseudo-second-order for adsorption process and isotherm was adequately defined by the Linear Langmuir isotherm model (KL) = 1.4, 1.2, 0.9 mg/l; (RL) = 0.020, 0.015, 0.013, respectively than Freundlich isotherm model. The Activation energy (Ea) of biosorption calculated were (131.10 KJ/mole) by using Arrhenius equation, and the thermodynamic parameters were ΔG⸰ (−41.03, −16.33, −16.12 KJ/mol), ΔH⸰ (−36.87 KJ/mol) and ΔS⸰ (−194.03 J/mol), respectively. These findings suggest that the removal process was based on chemisorption and the biosorption was exothermic. The result of the current experiment indicated that the IITISM22 could be an authentic biosorbent for Hg detoxification.