Robust superhydrophobic coatings featuring ZIF-67@cotton fabrics for efficient self-cleaning and versatile oil-water separation

Oiled wastewater generated from industrial processes inflicts significant harm on the environment, posting a pressing need for affordable materials that provide prospect for effective oil-water separation and the recovery of valuable oil resources from such wastewater. The incorporation of zeolitic imidazolate framework (ZIF) onto the commercial cotton fabric, due to its porous structure and adjustable properties, offers a promising solution to this challenge. In this work, a cotton fabric with multifunctionalities was designed by in situ growing ZIF-67 onto cotton (ZIF-67@Cotton). The robust superhydrophobic surface was successfully created on ZIF-67@Cotton by combining a self-roughness structure with the modification using a low surface energy agent. This modification imparts versatility, enabling self-cleaning, high-efficiency oil-water separation, and mechanical stability. The resulting ZIF-67@Cotton exhibits a desirable water contact angle (WCA) superhydrophobic characteristic (over 156°), and exceptional resistance to mechanical abrasion during laundering. Notably, this superhydrophobic ZIF-67@Cotton not only efficiently extracts oil from oil/water mixtures with a efficiency over 99.5 % and water-in-oil emulsion (99.3 %) after repeating 20 times but also exhibits superior UV resistance which introduces an innovative approach to develop next-generation multifunctional flexible fabrics featuring superhydrophilic and underwater superoleophobic surfaces.