Study On The Preparetion And Poperties Of Oil/Water Separation Materials Based On Copper Foam Substrates

The leakage of crude oil during mining and transportation,the discharge of oily sewage in industrial and daily life bring serious adverse effects to the surrounding ecological environment,and even endanger people's health and life safety.In order to reduce or eliminate the negative effects of oil leakage and oily wastewater,people have been working on a low-cost,low-energy,large-scale preparation of oil/water separation materials and technologies with efficient oil/water separation capacity and efficiency.Inspired by biological surfaces with special wettability in nature,researchers have developed a number of oil/water separation materials with special wettability.Most of these oil/water separation materials are based on a twodimensional metal mesh/film/fabric or three-dimensional porous sponge/foam.Oil/water separation materials can be prepared by constructing a multi-scale micro/nano composite structure on the surface of substrate and modifying it with different types of chemicals.Oil/water separation materials prepared from two-dimensional metal mesh/membrance/fabric are deficient in mechanical strength,oil/water separation ability and wetting stability,while oil/water separation materials prepared from three-dimensional porous sponge/foam generally have low mechanical strength,poor thermal stability,easy shrinkage deformation,and poor durability.These problems greatly limit the practical application of the oil/water separation materials.To solve the above problems of oil/water separation materials,three-dimensional porous copper foam,which has the advantages of light weight,high mechanical strength,good thermal stability,low shrinkage,and good durability,is selected as substrate in this work.Its skeleton structure and related properties are fully utilized to construct multi-scale micro-nano composite structure and then modified it with different chemicals to prepare a series of oil/water separation materials with special wettability surface based on copper foam.The surface morphology,chemical composition and wettability of the copper foam surface after different modification treatments were studied by using modern analytical techniques.The oil/water separation ability of copper foams of different modified treatments were evaluated by the self-designed separation device and separation experiment.The research results lay a theoretical and practical foundation for the design and preparation of durable oil/water separation materials with special wettability surfaces.The main contents of the study and the corresponding research results are as follows:(1)Using copper foam(CF)as substrate,a multi-scale micro-nano composite structure was constructed by in-situ deposition of silver nanoparticles on its surface by displacement reaction.Using organopolysilazane(OPSZ)with both organic and inorganic properties as the surface modification material,a highly hydrophobic copper foam(CF-Ag-OPSZ)based on an organopolysilazane coating was prepared.The results show that the obtained CF-Ag-OPSZ has stable high hydrophobicity/superlipophilicity,the water contact angle on its surface is 147°.The separation efficiency of CF-Ag-OPSZ for oil/water mixture is above 95.6 %.In particular,the separation efficiency remains about 98 % after repeated separation of the hexadecane/water mixture.CF-Ag-OPSZ has excellent mechanical durability,and the water contact angle of its surface remains at about 140° after 10 wear cycles.(2)Using OPSZ as anchor molecule,the modified organopolysilazane(OPSZ@DFMA)modified by dodecafluoroheptyl methacrylate was prepared by hydrosilylation reaction.Superhydrophobic copper foam(CF-Ag-OPSZ@DFMA)based on fluorine-containing compound modified organopolysilazane coating was prepared by applying dip-coating method to a copper foam with multi-scale micro/nano composite structure.The results show that the prepared OPSZ@DFMA both have OPSZ's anchoring properties to various substrates and the low surface energy characteristic of DFMA.The OPSZ@DFMA coating cured at room temperature has high thermal stability,strong adhesion and hardness.CF-Ag-OPSZ@DFMA based on OPSZ@DFMA coating has superhydrophobic/superlipophilicity,the water contact angle on its surface can reach 150.5°.CF-Ag-OPSZ@DFMA has high oil/water separation efficiency and separation capacity,its separation efficiency for a series of oil/water mixtures is higher than 96.2 %.In particular,the separation efficiency of CF-Ag-OPSZ@DFMA to hexadecane/water mixture can reach 98.6 %.CF-Ag-OPSZ@DFMA has excellent mechanical durability,and the water contact angle of its surface remains at about 141° after 10 wear cycles.In addition,CF-Ag-OPSZ@DFMA has excellent chemical resistance.The water contact angle on CF-Ag-OPSZ@DFMA surface maintained at about 150° after being soaked in strong acid,strong alkali or salt solution for 24 hours.(3)Using dopamine hydrochloride as anchor molecule,a stable polydopamine(PDA)coating was formed on surface of CF,then the silver nanoparticles were deposit on the surface to construct a stable multi-scale micro-nano composite structure,the strong adhesion and reduction properties of the PDA were fully utilized in this process.Finally,long-chain alkyl mercaptans(NDM and MUA)with methyl and carboxyl groups at the end respectively were used as surface modified substances to modify copper foam through self-assembly process to prepare mussel-inspired pH-responsive copper foam(CF-PDA-Ag-SH).The results show that the obtained CF-PDA-Ag-SH has good pH responsiveness,it maintains high hydrophobicity under acidic and neutral conditions,the water contact angle on its surface is about 140°;it is superhydrophilic under alkaline conditions,the water contact angle on its surface is 0°.CFPDA-Ag-SH is suitable for bidirectional separation of oil/water mixtures.CF-PDA-Ag-SH has high separation efficiency and separation ability for a series of oil/water mixtures.In particular,the separation efficiency of CF-PDA-Ag-SH to 1,2-dichloroethane/water mixture reaches 98.2 %.The octane/water mixture maintains a separation efficiency of about 98 % and stable wettability.CF-PDA-Ag-SH has excellent mechanical stability,and the water contact angle of its surface remains at about 130° after 10 wear cycles.