Manipulating surface wettability of SiC MF membranes for high permeance and antifouling performance in sugarcane juice clarification

Ceramic membranes ultrafiltration (UF) has emerged as a promising alternative to the conventional clarification technology in sugarcane juice clarification industries, given their efficient and eco-friendly separation processes based on the size sieving effect. However, the upscaling application of ceramic UF membranes is still limited by their low permeate flux, high energy consumption and severe membrane fouling. Herein, to utilize the interactions at the interfaces, tubular SiC microfiltration (MF) membranes with special surface wettability were deliberately tailored through a novel penetration pressure counter-balanced crossflow method using 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane as a hydrophobic agent. The effect of an out-layer pressures (0-4.0 kPa) and flow rate (1.4-2.4 mL·s -1 ) on surface wettability of membranes were studied, and those obtained membranes were applied in sugarcane juice clarification. The wettability, functional groups, binding energy, chemical compositions, and microstructure of modified SiC membranes were analyzed to elucidate their wettability-performance relationships. The performance of modified SiC MF membranes in sugarcane juice clarification were mainly evaluated by the flux decline profiles and permeate solution turbidity. The SiC membrane with hydrophobic inner wall (WCA=142°) and hydrophilic outer surface (WCA=0°) were achieved at out-layer pressure of 2.0 kPa and flow rate of 1.9 mL·s -1 . The results show that the SiC membrane with such asymmetric wettability exhibited ultra-high stable permeate flux (844 L·m -2 ·h -1 ·bar -1 ), satisfactory turbidity reduction rate (95.7%), and relatively low flux decreased rate (64.4%). The improved antifouling performance can be primarily attributed to the hydrophobic inner wall, and negatively charged pore wall. This work primarily demonstrates the application potential of ceramic MF membranes with asymmetric wettability for the effective sugarcane juice clarification.