Adsorption kinetic and species variation of arsenic for As(V) removal by biologically mackinawite (FeS)

Biologically mackinawite was synthesized by FRB and SRB culture solutions, which had been shown a crucial role in removal arsenic under anaerobic environment. To investigate the changes of arsenic species in aqueous by As(V) sorption onto biologically FeS, As(III/V) in aqueous were detected by HPLC-AFS. And the solid phase was characterized by XRD, XPS, and BET. The adsorption envelope of As(T) shown the high uptake occurred at pH 5. The adsorption kinetics followed the pseudo- second- order model and the isotherm followed by Langmuir equilibrium for different solid/solution ratios. The maximum sorption capacities were 237.45 mg/g (0.05 g/L FeS), 160.45 mg/g (0.1 g/L FeS), and 56.71 mg/g (0.2 g/L FeS), respectively. The results showed that sorption for As(V) sorption by FeS decreased with increased in solid/solution ratios. Our results showed that As(V) was reduced to As(III) or lower valences in As(V) sorption experiments. The results showed that the As(others) dominated in the batch experiments and the As(V) was the main state in the column experiments. The XPS date suggested that the FeS particles were effective for reduce As(V) and the As(others) were possibly As-S and As-As complexes.