Facile fabrication of antibacterial membranes with human-friendly aloin for water purification

Currently, chemicals or nanoparticles are widely used for modifying membranes to improve their antifouling properties. However, the chemicals released, particularly during long-term water or wastewater filtration, are highly toxic to the environment and humans. Herein, an herb-inspired, green antibacterial membrane with exceptional sustainable antifouling properties was developed using aloin. The resultant membranes exhibited excellent bacterial inactivating efficiency because of the electrostatic interactions between the amine groups on the membrane and the bacterial cells, which contributed to cell deformation. The aloin molecules also significantly increased reactive oxygen species levels, causing oxidative damage to bacterial cells. Moreover, the functional decorative layer, which exhibited remarkable resistance to bacterial adhesion because of the abundant hydroxyl, carbonyl, and amino groups in aloin, endowed the as-prepared membranes with strong polarity, reducing bacterial adhesion and biofilm formation. When applied in a membrane bioreactor, the aloin-modified membranes demonstrated a >27.0% lower fouling rate than commercial microfiltration membranes. Overall, the successful fabrication strategy and material features described offer a green alternative for membrane development and provide new avenues for the design of healthcare materials such as wound dressings.