Optimization of the operational parameters for a 50 nm ZrO2 ceramic membrane as applied to the ultrafiltration of post-electrodeposition rinse wastewater

A 50 nm ZrO2 ceramic ultrafiltration membrane was evaluated with respect to model wastewater containing a 5% v/v suspension of cathodic electrodeposition paint particles (positively charged). The influence on filtration performance of operating parameters such as crossflow velocity (CFV), transmembrane pressure (TMP) and particle size distribution was investigated. Results show a combination of high CFV and low TMP to be beneficial — typified by a CFV of 3.2 m s−1 and TMP of 100 kPa. Under these operating conditions, the measured steady-state permeate flux was found to be the highest with optimum energy consumption. On the other hand, high pressures and high CFVs produce unfavorable outcomes, with relatively low steady-state permeate fluxes and high energy consumption. It was also shown that the dominant membrane resistance was due to concentration polarization. Concentration polarization resistances (RG) were found to be the highest at high TMPs. At higher pressures, the effect of CFV is negligible and the rate of particle deposition is directly proportional to the TMP. A minimization of concentration polarization at a CFV of 3.2 m s−1 and a TMP of 100 kPa was shown to be a result of the larger particles being swept away from the membrane surface and a concomitant alleviation of pressure compression.

► 50 nm ZrO2 ceramic membrane evaluated with respect to CED paint particles suspension.
► High CFV and low TMP shown to be the beneficial operating conditions.
► Concentration polarization was found to be the dominant membrane resistance.
► Concentration polarization minimized at CFV of 3.2 m s−1 and TMP of 100 kPa.