Effect of pH on fouling attachments and power consumption in ultrafiltration of latex solution

Abstract

The goal of the present study was to remediate ultrafiltration fouling through the altering of the latex paint solution pH, in order to reduce the total mass fouling and the specific power consumption. Polycarbonate flat membrane with a pore size of 0.05 µm was used under a constant feed flow rate and cross‐flow mode in ultrafiltration of a latex paint solution. It was observed that the ionic strength of the latex solution had a significant effect on the membrane hydrophilicy and the particle surface charge, which in turn influenced the particle–particle and particle–membrane attachment. At the transmembrane pressure of 15 psi, a feed flow rate of 1 LPM, and a feed concentration of 1.3 kg/m3, increasing solution pH from 7 to 12 resulted in a considerable 50% reduction in membrane fouling. This reduction of fouling led to a 53.9% decrease in the specific power consumption, while the permeate flux increased by 97.4%. On the other hand, the mass of fouling noticeably decreased by 35.8%, the permeate flux increased by 64.5% and the specific power consumption dramatically increased by 127.5%, when the feed flow rate was increased from 1 to 4 LPM at the solution pH of 7. Alternatively, when the feed flow rate and the solution pH were increased simultaneously, the mass of fouling was reduced by 56.8%, with an improvement in the specific power consumption augmented only by 54.1%, while the permeate flux increased by 136.84%.