Superoleophilic cotton fabric decorated with hydrophobic Zn/Zr MOF nanoflowers for efficient self-cleaning, UV-blocking, and oil–water separation

Abstract

Oil spills significantly threaten aquatic life, human health and the environment, necessitating oil–water separation methods. To address these environmental concerns, a hydrophobic Zn/Zr bimetallic metal–organic framework nanoflowers (H-Zn/Zr MOF-NF) functionalized superhydrophobic cotton fabric is developed for oil–water separation. Hydrophilic amine-terminated bimetallic Zn/Zr MOF with distinctive flower-like morphology is hydrothermally synthesized and functionalized with myristic acid. Finally, cotton fabric is coated with a hydrophobic emulsion of H-Zn/Zr MOF-NF and polydimethylsiloxane (PDMS) via dip-coating,enhancing surface roughness and lowering surface energy. The developed superhydrophobic cotton fabric shows exceptional water-repellency with a water contact angle (WCA) and water slidingangle (WSA) of 161° and 4°, respectively. The Zn/Zr MOF-NF coated superhydrophobic cotton fabric with a porous structure efficiently separates diesel oil, n-hexane, toluene, and chloroform from water mixtures with over 98% separation efficiency and high flux. The coated cotton fabric demonstrates remarkable reusability, upholding superior separation efficiency over 95% and retaining WCA at 156° after 12 cycles with excellent physical and chemical stability. The modified cotton fabric also exhibits enhanced UV-blocking properties and self-cleaning characteristics. The designed emulsion is also applied to other surfaces, such as sponge, wood, and filter paper, demonstrating promising superhydrophobicity. This study opens new possibilities for manufacturing multifunctional superhydrophobic surfaces for oil–water separation applications using bimetallic hydrophobic MOFs.