CALCULATION OF LIMITING FLUXES IN THE ULTRAFILTRATION OF COLLOIDS ANDFINE PARTICULATES

A very strong particle charge dependence of the pressure independent f lux has been demonstrated in the ultrafiltration of colloids. This flu x passes through a minimum both as the charge of the particles increas es, for constant particle size, and as the particle size increases, fo r constant particle charge. By considering the force balance on a part icle and the flocculation of particles, the observed variation of expe rimental ultrafiltration flux have been modelled. The observed variati on in flux with particle size at high particle charge is predicted. Va riations in flux with particle charge are predicted for small particle s, r(p) less-than-or-equal-to 25 nm, at low and high particle charge a nd for larger particles, r(p) greater-than-or-equal-to 100 nm, at high particle charge.