| In recent years,the frequent occurrence of crude oil leakage accidents and the discharge of oil-bearing industrial wastewater pose a great threat to the natural environment and human health.Many researchers are looking for ways to solve the problem,among which the super wettable oil-water separation materials emerge as the times require.According to the different wettability of the materials to water and oil,the materials can be divided into superhydrophobic-superoleophylic and superhydrophilic-underwater superoleophobic.Among them,superhydrophobic-superoleophylic materials are easy produces scale,easy to be blocked by oil,low separation efficiency,and need additional conditions in the separation process,while superhydrophilic-underwater superoleophobic materials have high separation efficiency,excellent water flux,good anti oil scaling performance and recyclability.In addition,the superwettable oil-water separation materials can be divided into single wettability materials and intelligent response switchable wettability materials.The intelligent response switchable wettability materials overcome some disadvantages of single superwettability materials because of the intelligent transformation of wettability on the surface,which has aroused great interest of researchers.This paper mainly studies the preparation of intelligent response switchable wettability materials and superhydrophilic underwater superoleophobic materials and their application in oil-water separation.The research content is divided into the following three parts.(1)3-(Trimethoxysilyl)propyl methacrylate,tridecyl methacrylate and undecanoic acid were introduced into the fabric surface by in-situ radical polymerization,and the surface roughness was provided by adding SiO2 nano ions,thus an intelligent superwetting fabric with switchable wettability was obtained.The intelligent superwetting fabric has excellent friction resistance and tensile properties,and can be used for controllable and efficient separation of various oil-water mixtures and three-phase oil-water mixtures,with separation efficiency as high as 99%.Therefore,the superwetting fabric can be an ideal choice for the treatment of oily wastewater in various harsh environments.(2)The ZIF-67@Cu(OH)2 nanowire array-coated copper mesh membrane prepared using chemical oxidation and self-assembly method.These freshly prepared copper meshes with micro/nano secondary rough structure exhibit excellent superhydrophilicity and underwater superoleophobicity.Thus,the as-prepared mesh membrane can be used for oil-water separation with excellent separation capability.It shows extremely high oil-water separation efficiency(99%),excellent cycling ability as well as high permeation flux(23854 L·m-2·h-1)in several typical oil-water separation processes.The mesh membrane also exhibits excellent underwater superoleophobicity in different pH values conditions.In addition,the as-prepared mesh membrane shows excellent durability and stability.Consequently,this work provides an economical and effective method for modification on metal substrate to prepare a superhydrophilicity/underwater superoleophobicity material to realize efficient separation of oil-water mixture.(3)The combination of copolymer PAA-co-PTMSPMA and micro nano particles as the modification system was used.Then the PVDF membrane was immersed in the modified system for hydrophilic modification.PVDF membrane with excellent underwater superoleophobicity was prepared by this strategy.At the same time,the oil droplets on the modified PVDF membrane can maintain stable spherical shape in acidic and alkaline water environment,and show stable oil repellent performance in extreme environment.In addition,the separation efficiency of the modified superhydrophilic PVDF membrane was still greater than 98.6%after 10 cycles of oil in water emulsion separation.Therefore,this work provides the feasibility for obtaining super hydrophilicity and polymer membrane and applies it to the separation of oil-water emulsion. |
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