Robust self-cleaning urchin-like Ni/Co LDH stainless steel mesh for gravity-driven oil/water emulsion separation and catalytic degradation of aromatic dyes

In the face of frequent oil spills and dye emissions, membrane technology is an efficient method to treat wastewater. However, selectivity , membrane fouling and high operating pressure are tricky problems for practical membrane applications. Hence, it is desirable to design a novel membrane with high selectivity, high flux and superior antifouling properties for gravity-driven separation of complex oily wastewater. In this study, bioinspired by sea urchins with good self-cleaning properties, an urchin-like Ni/Co layered double hydroxide (LDH) surface was grown onto stainless steel mesh (SSM) via a facile hydrothermal method . Due to the unique hierarchical architecture and surface chemistry, Ni/Co@SSM displays a robust self-cleaning oil-repellent ability without hydration. Combining the unique superwettability and highly porous nanostructure , Ni/Co@SSM could be used to separate various oil/water mixtures and emulsions efficiently under only gravity-driven conditions. In addition, Ni/Co@SSM exhibits great catalytic degradation ability of dye solutions in a short time. Notably, Ni/Co@SSM displays excellent physical, chemical and thermal stability in acidic, alkaline and saline environments. Consequently, Ni/Co@SSM possesses broad application prospects with superior self-cleaning and outstanding catalytic degradation ability of aromatic dyes. It shows promising application value in practical complex oily wastewater treatment without complicated operations and chemicals.