Mercury removal from aqueous solution by dried biomass of indigenous Vibrio parahaemolyticus PG02: Kinetic, equilibrium, and thermodynamic studies

• The dominant mechanism in the first 15 min of biosorption process was ion-exchange.
• Intraparticle diffusion was not the sole rate-limiting step.
• Pseudo-second order model described biosorption data in all range of contact time.
• 9.63 × 10−4 mol g−1 was the maximum Hg2+ sorption capacity at optimum conditions.
• The Hg2+ biosorption process by PG02 was physical, spontaneous, and endothermic.

In this study, for the first time the potential use of dried Vibrio parahaemolyticus PG02 to remove mercury from synthetic effluent was investigated by considering equilibrium, kinetic, and thermodynamic aspects. The results indicated that Hg2+ biosorption was best described by the pseudo-second order model. In addition, it was found that intraparticle diffusion was not the sole rate-limiting step. The ion-exchange mechanism was a predominant biosorption mechanism in the first 15 min of contact. The Langmuir isotherm better described the equilibrium data of Hg2+ biosorption than the Freundlich isotherm. According to this model, the maximum biosorption capacity was found to be 9.63 × 10−4 mol g−1 at optimum conditions (pH = 6.0 and temperature =35 °C).