Two-dimensional superhydrophobic metal–organic monoacid framework composite meshes with exceptional chemical stability for oil/water separation

Metal-organic frameworks (MOFs) possess versatile architectures, large surface area, and customizable chemical functionalities, which provide them great opportunities in a variety of applications. However, the applications of MOFs are limited due to their weak chemical stability under humid conditions. In this research, a new class of intrinsically superhydrophobic two-dimensional (2D) Metal (zinc)-organic monoacid frameworks-oleic acid (ZOmAF-OA) was fabricated to improve the chemical stability in the aqueous environment. In the meantime, an ultra-facile seeding-free approach to fabricating ZOmAF-OA composite stainless steel (SS) mesh was reported. A thick, continuous layer of well-intergrown ZOmAF-OA nanosheets was successfully synthesized on various stainless steel meshes at ambient conditions. The ZOmAF-OA-SS composite mesh demonstrated extraordinary chemical stability even in harsh conditions. The ZOmAF-OA coatings exhibited excellent stability with their coverage and morphology remaining intact even after 30 days in concentrated NaCl solution. More importantly, the ZOmAF-OA-SS composite mesh retained its superhydrophobicity after 30 days in an acidic solution with no apparent damage to the coating. The ZOmAF-OA-SS composite mesh demonstrated excellent oil/water separation performance for a variety of oil/water mixtures with separation efficiencies up to 98.3 ± 1.4 %.