Biosorption of arsenic (III) from aqueous solution by living cells of Bacillus cereus.

In this work, removal of arsenic (III) from aqueous solution by living cells (Bacillus cereus), biosorption mechanism, and characterization studies have been reported. B. cereus cell surface was characterized using SEM-EDX and FTIR. Dependence of biosorption on pH of the solution, biosorbent dose, initial arsenic (III) concentration, contact time, and temperature had been studied to achieve optimum condition. The maximum biosorption capacity of living cells of B. cereus for arsenic (III) was found to be 32.42 mg/g at pH 7.5, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data of arsenic (III) are fitted to linearly transformed Langmuir isotherm with R (2) (correlation coefficient) >0.99. The pseudo-second-order model description of the kinetics of arsenic (III) is successfully applied to predict the rate constant of biosorption. Thermodynamic parameters reveal the endothermic, spontaneous, and feasible nature of sorption process of arsenic (III) onto B. cereus biomass. The arsenic (III) ions are desorbed from B. cereus using both 1 M HCl and 1 M HNO(3).