Membrane fouling mechanisms during ultrafiltration of skimmed coconut milk

• To investigate the membrane fouling during UF of skimmed coconut milk.
• Fouling mechanism was evaluated using Hermia’s model ((d2t/dV2) = k(dt/dV)n).
• 20 kDa PSF membrane at 60 °C and 1.8 bar encouraged the most severe membrane fouling.
• All fouling were dominated by standard, intermediate blocking and cake formation.

Ultrafiltration is a promising technique to produce value-added products from skimmed coconut milk. Unavoidably, membrane fouling always hinders the membrane performance. In this work, Hermia’s models were used to investigate the fouling mechanisms. Effects of the molecular weight cut-off of the polysulfone membrane (10, 20 kDa), feed solution temperature (50, 55, 60 °C) and operating pressure (1.8, 2.0, 2.2, 2.4 bar) towards the membrane fouling were analysed. The results showed that the best fit (R2 ⩾ 0.98) of the experimental data to all fitted fouling mechanisms (complete blocking, standard blocking, intermediate blocking and cake formation) occurred for experiments using a 20 kDa polysulfone and 60 °C feed temperature. All fouling mechanisms were present during the ultrafiltration but dominated by complete blocking, followed by standard, intermediate blocking and cake layer formation. The characteristics of the membrane and feed solution were found to be highly influential on the membrane fouling mechanisms in this study.