2015 Volume 41 Issue 2 Pages 113-120
To clarify the effect of the liquid environment on the filtration of fine particle suspensions by a sintered metal filter, filtration experiments of bacterial suspensions of Bacillus atrophaeus in water of various pH values or aqueous organic solvents of various concentrations were conducted, and the particle retention performances of the sintered metal filter were evaluated. In the water system, a decrease in pH led to a decrease in the absolute value of zeta potentials of both filter and bacterial particles. In an aqueous organic solvent system, an increase in concentration of organic solvents caused both a decrease in the absolute value of zeta potentials and a decrease in the permittivity of liquid medium. As a result, the particle retention performance tended to be improved by a decrease in the electrostatic repulsion between filter and bacterial particles in liquid. Moreover, the retention of bacterial particles by the sintered metal filter could be explained quantitatively by the interaction between the surfaces of filter and bacterial particles described through an analysis based on DLVO theory.