A combined model for describing the trans-membrane pressure (P) variation in constant flux dead-end microfiltration (MF) process

Abstract

In present paper, a constant flux model was established by dividing the trans-membrane pressure (P) into the partial pressure of the membrane layer (Pm) (originating from the pore blocking/shrinking resistance of the membrane and the inherent membrane resistance) and the cake layer (Pc) (originating from the resistance of the deposited cake layer) in constant flux dead-end filtration process with complex fouling mechanism. The pore resistance (Rp) and the available membrane area ratio (A/A0) were determinated by using Hagen-Poiseuille law. In addition, the variations of model parameters (Km, Kp, Kc and K) in the filtration process before and after hydraulic/ultrasonic cleaning process were also discussed. Results showed that the model predictions had good agreements with experimental data at different conditions by using Bovine Serum Albumin (BSA) (R2 =0.99), Humic acid (HA) (R2 = 0.99), Sodium Alginate (SA) solutions (R2 =0.99) and activated sludge (R2 =0.99), kaolin (R2 =0.99) and titanium dioxide suspensions (R2 =0.99). Meanwhile, the available membrane area ratio decreased in the initial stage (pore blocking/shrinking and cake filtration) and keep constant in the following stage (cake filtration). Moreover, the variation of available membrane area ratio before and after hydraulic/ultrasonic cleaning process can be give a guidance to optimize the membrane cleaning process.