Investigating Flux Decline and Fouling Mechanisms in Ultrafiltration of Soy Protein Using a 10 kDa Hollow Fiber Membrane Module

This study addresses significant challenges in ultrafiltration (UF), specifically fouling and flux decline, encountered during soy protein concentration using a 10 kDa hollow fiber UF membrane module. It examines various resistances contributing to flux decline, including intrinsic membrane resistance, reversible resistance due to adsorption, irreversible resistance from pore blocking, and cake layer resistance. Utilizing a resistance-in-series model, the research quantifies the contributions of these resistances to flux decline at different transmembrane pressures (TMP). Results indicate that at lower TMP, adsorption resistance constitutes a substantial portion (30.07%) of the total resistance after one hour of operation. As TMP increases, cake layer resistance becomes predominant, comprising 73.31% of the total resistance at 1.518 bar TMP compared to 51.5% at 0.828 bar TMP. Additionally, the initial rapid decline in permeate flux (22%-24% within the first 30 min) is primarily attributed to concentration polarization. Future work could explore the development of more effective cleaning protocols or membrane modifications to mitigate cake layer buildup and reduce irreversible fouling. Furthermore, a deeper investigation into the role of concentration polarization and its interplay with other resistances could lead to enhanced design strategies for industrial-scale protein processing, ultimately improving efficiency and reducing operational costs in food and beverage applications.