Co/Al LDH-based dual superlyophobic honeycomb-like surfaces for on-demand oil/water separation and dye degradation

Wastewater from industrial processes usually contains insoluble oil slick and soluble organic dyes. Thus, it is of great significance to design novel materials for the simultaneous oil/water separation and dye removal in efficient wastewater purification. In this study, polydopamine (PDA) was firstly self-polymerized on PET textile to obtain PET@PDA. Then, a honeycomb-like Co-Al LDH layer grafted on the PET@PDA via a hydrothermal method to fabricate the PET@PDA@LDH. Finally, TiO2 nanoparticles were intercalated into the LDH nanosheet layer crosslinking with polyethyleneimine (PEI), obtaining PET@PDA@LDH@P-TiO2 membrane. By adjusting their hierarchical architecture and surface chemistry, PET@PDA@LDH@P-TiO2 membrane exhibited dual superlyophobicity of underwater superoleophobicity and underoil superhydrophobicity. Combining its unique superwetting property and porous structure, PET@PDA@LDH@P-TiO2 membrane could be applied for the gravity-driven on-demand separation of various oil/water mixtures. More importantly, the PET@PDA@LDH@P-TiO2 membrane exhibited good absorption and photocatalytic degradation performances to various organic dyes under UV illumination. Thus, without complicated operations and toxic chemicals, the dual-functional fabric shows great potential applications in complex oily wastewater remediation.