Ca(2+)-Facilitated Adhesion of Bacteria on the Na-Montmorillonite Surface

[Image: see text] The adhesion of bacteria on clay surfaces strongly affected their migration and distribution in soil and water. Bacterial adhesion experiments on the Na-montmorillonite (Na-MMT) surface were conducted to determine the role of Na-MMT in the bacterial adhesion process and to prove the validity of the isotherm and kinetic theory for the bacterial surface adhesion in the presence of Ca(2+) ions. Batch adhesion experiments with bacteria on the Na-MMT surface were carried out with varying time frames, temperatures, bacterial concentrations, and Ca(2+) ion concentrations. The adhesion capacity of Na-MMT significantly correlated with the Ca(2+) ion concentration, temperature, time frame, and bacterial concentration when Ca(2+) ions were present. The adhesion morphology of the bacteria onto the Na-MMT surface, observed through the zeta-potential and atomic force microscopy (AFM), additionally demonstrated that the bacterial adhesion onto the Na-MMT surface was dominated by the nonelectrostatic force.