Hydrophilic regulation of ceramic membrane surface for efficient treatment of algae wastewater

As a cutting-edge method, membrane separation technology effectively addresses high-algae water, mitigating the threats posed by it to public health and environmental sustainability, especially ceramic membranes. Ceramic membranes with stable physical and chemical properties exhibit remarkable permeance and superior rejection performance in algae-laden water treatment, yet their large-scale deployment is impeded by serious membrane fouling. Here, we propose a facile strategy to prepare anti-fouling ceramic membranes by depositing multifunctional coatings on the surface through soaking in a blend solution of PDA and KH560 to tailor the surface structure and hydrophilicity. The introduction of multi-functional coating optimized the physical and chemical structure of the surface, thereby increasing the hydrophilicity of the membrane and reducing surface roughness and pore size. As a result, the pure water flux of the modified membrane increased by 38.4 % compared with the original membrane, and the modified membrane exhibited a reduction in irreversible fouling from 5.0 % to 2.5 % and also an increase in flux recovery from 79.7 % to 98.6 %. Interestingly, the dissolved organic carbon (DOC) and the UV₂₅₄ removal rates of the filtrate decreased by 63.2 % and 75.6 %, respectively. Notably, dead algae cells and extracellular organic matter (EOM) were identified as the main factors inducing irreversible fouling of the membrane during the filtration process, and furthermore, the modified membrane alleviated the irreversible fouling via multiple mechanisms including the Donnan effect and pore size screening. Overall, the study provides a new solution and theoretical basis for the development of anti-fouling ceramic membranes.