Surface Functionalization Strategy for Cellulose Membranes Based on Silanization and Thiol–Ene Click Chemistry

Cellulose membranes (CMs) are garnering significant interest in water purification due to their abundant, renewable, and biodegradable properties. Surface functionalization of CMs provides a promising avenue to equip them with diverse functionalities, thus expanding their application spectrum. In this study, we introduce a simple, efficient, and versatile method for CM functionalization, utilizing silanization and thiol–ene chemistry. We demonstrate that these reactions proceed rapidly within minutes, endowing the origin CMs with various functional groups including perfluoroalkyl, thiol, and amino groups. We then explore the distinct properties and potential applications of the three functionalized CMs. The perfluoroalkyl-functionalized membranes display superhydrophobicity with a water contact angle of 154° and show excellent separation efficiency for various water-in-oil emulsion. The thiol-functionalized membranes exhibit strong adsorption capacity for the heavy metal Pb2+, coupled with satisfactory reusability. Lastly, the amino-functionalized membranes, quaternized with benzyl bromide, exhibit robust antibacterial properties against both Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). We believe that the efficiency and versatility of the functionalization method pave the way for creating advanced functional CMs suitable for a range of applications, from oily water treatment and metal remediation to bacterial rejection.