Abstract:Desulfovibrio vlugaris miyazaki SRB and Acidiphilumcryptum JF-5 are two common reductive microorganisms in the wastewater and sediments of acid mines. The two bacteria were used to synthesize the nano FeS and coat it on the surface of limestone. Dissolution kinetics experiments were conducted to investigate the influence of different nanometer FeS cladding layers on limestone dissolution and neutralization capacity, and dissolving model was set up based on the Frick's first law. The result of X-ray diffraction of coating layer on limestone surface indicates that it is mackinawite. The photoelectron spectroscopy (XPS) result further shows that the valence of Fe in coating layer is +2, and S valence is -2, the coating layer has obvious passive effect on the dissolution of limestone, the neutralization capability decreases with the increase of the layer's thickness, and the existence of the thick coating layer can make the final pH decrease to 1.5 pH compared with the final pH 6.5 of pristine limestone. The dissolution behavior of limestone in the presence of the coated mackinawite can be described as nCa,sol=At1/2-nCa,grp, in which nCa,grp value could represent the amount of secondary CaSO4 formed on the surface.