Application of electric fields to clean ultrafiltration membranes fouled with whey model solutions

• ZrO2–TiO2 UF membranes of 15 and 50 kDa were fouled with whey model solutions.
• Effect of protein concentration on cleaning efficiency (HCE) was investigated.
• Influence of NaCl presence, temperature and applied potential on HCE was studied.
• Electric fields applied with NaCl allow to completely clean the 15 kDa membrane.

In this work, the effectiveness of electric fields to clean two ZrO2–TiO2 ultrafiltration (UF) membranes fouled with three types of whey model solutions was investigated. Membranes tested had different molecular weight cut-offs (MWCOs) (15 and 50 kDa). Whey model solutions consisted of aqueous solutions of bovine serum albumin (BSA) at 10 g L−1, a mixture of BSA (10 g L−1) and CaCl2 (1.65 g L−1) and whey protein concentrate (WPC) (total protein content 45%) solutions at different concentrations (22.2, 33.3 and 150.0 g L−1). The hydraulic cleaning efficiency (HCE) achieved by means of the application of the electric fields was evaluated as a function of the membrane MWCO and the operating conditions of the cleaning technique (applied potential, temperature of the cleaning solution and concentration of NaCl). The results demonstrated that the presence of NaCl favoured the removal of protein deposits on the membrane layer. On the other hand, the higher the temperature of the cleaning solution and the applied potential were, the higher HCE was achieved. Regarding the membrane MWCO, the permselective properties of the 15 kDa membrane were completely recovered after the cleaning procedure by electric field for all the feed fouling solutions tested, whereas this technique could not completely remove the protein deposits on the 50 kDa membrane when BSA solutions were used as feed.