engleski

Microfiltration of Cutting-Oil Emulsions Enhanced by Electrocoagulation

Electrocoagulation (EC) was examined as a pre- treatment to the microfiltration (MF) of oily emulsions within the metal working industry. The aim of this pre-treatment was to improve the MF performance in terms of flux decline and removal of oil by applying the minimum time of EC pre-treatment. Aluminium electrodes were used in EC, and flat sheet regenerated cellulose membrane in MF. The experiments were carried out using cutting-oil emulsions at different concentrations (0.1, 0.5 and 1.0% (v/v)) and conductivity of about 700 μS cm-1. Drop size and zeta potential distributions were carried out to evaluate the impacts of EC time on zeta potential and average particle size. We found that in all emulsions 10 min of EC made the average size of oil particles bigger that the average size of the pores in MF and substantially reduced pore clogging and irreversible fouling. Reduced flux decline was related to the continuous formation of Al(OH)3 in EC, that interconnected the colloidal oil particles into porous and irregularly-shaped flocs which formed highly porous cake layer on the membrane surface.

microfiltration; electrocoagulation (EC); cutting-oil emulsion; cake layer; flux decline; zeta potential

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