Mussel-inspired modification of cotton fabric with aluminum-based MOF and chitosan for oily wastewater treatment

Oily wastewater pollution poses a serious environmental challenge, driving the development of efficient, stable, and multifunctional purification materials for treating complex wastewater. In this study, a composite coating was constructed by integrating a metal-organic framework (MOF, CAU) for high surface area, polydopamine (PDA) for strong adhesion, and chitosan (CS) for hydrophilicity. The coating was deposited onto cotton fabric (CF) via a simple immersion method. The resulting polydopamine-chitosan-CAU@ cotton fabric exhibits superhydrophilic and underwater superoleophobic properties, with an underwater oil contact angle of up to 160°. It enables efficient oil-water separation across various oil phases and harsh conditions (acidic, alkaline, high-salinity). After 10 cycles, separation efficiency remains 98 % for petroleum ether-water mixtures. Furthermore, the coated fabric adsorbs cationic dyes (methylene blue) and shows antibacterial activity. These results highlight the significant potential of polydopamine-chitosan-CAU modified cotton fabric in the purification of complex oily wastewater.