Experimental Study On Ultrafiltration Of Protease Zymotic Fluid And Cleaning Of The Fouled Membrane

In the paper, the concentration of protease zymotic fluid with ultrafiltration technique was systematically investigated. Three kinds of PES (Polyethersulfone) membranes with different molecular weight cut-off were presented for filtration. Based on the steady permeate flux and the loss of enzyme activity, the membrane with 10000 Da molecular weight cut-off was chosen for following filtration experiments.The effect degree of operation conditions and three interplays of operation condition on filtration were studied with the orthogonal experimental method,and the suitable operation conditions for filtration were determined through the further study on the relation between operation conditions and steady permeate flux.The composition of filtration resistance was also analyzed at different operation condition in this paper, which is vital for the better understanding of membrane fouling regime, the reduction of membrane fouling and the introduction of new ideas for membrane cleaning.The SEM photographs were taken on the membrane surface,the membrane supporter and the cross-section of new membrane and fouled membrane. The fouling status after filtration was discussed and the main filtration resistance was therefore thought to be cake layer resistance. In the paper, the chemical cleaning of fouled membrane was also studied in detail.The concentration,the time for cleaning and the temperature of each cleaning agent during membrane cleaning were evaluated and the cleaning efficiency of cleaning agent was assessed and compared. Based on the research about membrane cleaning above, an ideal fouling strategy was presented for the cleaning of fouled membrane.