Mechanism and kinetics of Zn(II) removal from wastewater by immobilised beads of SRB sludge.

The treatment of Zn(II)-bearing wastewater by immobilised Sulfate Reducing Bacteria (SRB) sludge beads of inner cohesive nutrient source was investigated, by which the traditional problems in SRB methods were resolved. The mechanism and kinetics model on Zn(II) removal were studied. The results showed that SO42− was reduced to S2− on the surface of SRB sludge beads, and Zn(II) precipitated outside beads. The effect of internal diffusion could be neglected, and the chemical reaction was the rate determining step. The reaction kinetics was followed by Micaelis-Menten formula, and the constants, Ks and vmax were 8.99 mg⋅L−1 and 0.018 mg⋅L−1⋅s−1, respectively.