NaCl cleaning of 0.1 μm polyvinylidene fluoride (PVDF) membrane fouled with humic acid (HA)

In this work, the fouling resistance of 0.1 μm PVDF microfiltration membrane fouled with humic acid (HA) solution during NaCl cleaning process was systematically studied. Based on mass balance between foulant dissolution and foulant re-deposition on the membrane surface or in membrane pores, a new general expression of cascade kinetic models was established for the first time to predict the variation of instantaneous fouling resistance during NaCl cleaning. The results showed that M1+1 model was the optimal kinetic model to predict the instantaneous fouling resistance of 0.1 μm PVDF membrane in NaCl cleaning process by comparing the experimental data with model predictions. Meanwhile, high flux recovery of 94.20% could be obtained at NaCl concentration of 100 mM with agitation speed of 600 rpm and temperature of 35 °C. In addition, the accuracy of M1+1 model was approved by a series of long-term experiments with several cleaning cycles, the other membrane and cleaning agent.