(TA-APTES)Plus: A rapid, green and universal coating for membrane modification toward oil-in-water emulsion separation

In our previous work, we have developed tannic acid (TA)-3-aminopropyltriethoxysilane (APTES) coating (TA-APTES coating) for membrane surface modification, which has several distinct advantages: suitable for various membranes, hierarchical structures, mild conditions, etc. In this work, we developed (TA-APTES)Plus coating, which exhibits much better performance than our previous TA-APTES coating: (1) Much faster: The membrane modification process based on our (TA-APTES)plus coating only needs 40 min, while our previous TA-APTES coating needs 12 h; (2) Much greener: The (TA-APTES)Plus coating is prepared in pure water system, without Tris-HCl buffer solution, without oxidants such as H2O2 or KIO4; (3) More stable: The (TA-APTES)Plus coating can remain superhydrophilic even after 30 days, which cannot be achieved by our previous TA-APTES coating. Moreover, the (TA-APTES)Plus coating reserves the advantages of our previous TA-APTES coating, such as universality and distinct hierarchical structures. Take polypropylene (PP) microfiltration membrane as an example, the PP membrane modified by (TA-APTES)Plus not only possesses ultra-high pure water flux (11,990 L m−2 h−1 bar−1) and high separation efficiency (>99.8%) of oil-in-water emulsion, but also exhibits excellent stability. Considering its much better performance, the (TA-APTES)Plus coating may become a more powerful tool for membrane modification toward oil/water separation.