A self-cleaning biocatalytic membrane with adjusted polyphenol deposition for edible oil-water separation

Abstract

Catechol-amine co-deposition membranes have garnered significant interest in enzyme immobilization, yet the deposited coating leads to excessive mass transfer resistance, negatively impacting membrane filtration performance. This work adjusts polyphenol deposition by utilizing the co-deposition structure with tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) with glycerol to enhance the filtration capability while maintaining enzyme activity. The glycerol addition has brought in a structural transition from dense nanosphere stacking to the loose flaky structure of greater bulkiness. Consequently, the resulting membrane showed a 69% of permeability improvement along with improved enzyme activity post-adjustment. In oil-water separation cycle tests, the biocatalytic membrane enabled the clarification of oil emulsions and facilitates offline self-cleaning, maintaining high permeability and recovery even after five cycles of heavy oil (4 g/L) filtration, showing great application potential in edible oil-water separation. The biocatalytic membrane of this work, derived from biomass and characterized by its facile preparation and minimal mass transfer resistance, presents a promising avenue for the integration of biocatalysis with filtration technologies within industrial production processes.