Preparation Of Special Wettability Copper Mesh And Application In Oil/Water Separation

Special wettability is a common biological phenomenon of surface in the nature as well as a very important feature of modern bionic materials. In recent years, special wettability materials have attracted widest attention, especially for the preparation of superhydrophobic superoleophylic and superhydrophilic underwater superoleophobic materials and their application in oil/water separation. As a kind of common and accessible metal mesh, Cu mesh has strong metal toughness and stability. This article researched several preparation methods of copper mesh with special wettability and their application in oil/water separation, the main research content is as follows:At the first, the copper mesh of superhydrophobic superoleophilicity was prepared on a rough copper mesh through chemical etching method followed by self-assembly with low surface energy substances. It was based on the control of chemical etching condition in acid environment and modification condition in which lauric acid, stearic acid or twelve thiol solution were used for self-assembly respectively. The copper mesh with 164.3° of water contact angle was prepared by changing both the surface microstructure and chemical composition. The influence of concentration of FeCl3 solution, etching time, modified liquid and modification time on the copper mesh with special wettability were discussed. The changes of special wettability on copper mesh in different corrosion environment were also discussed. After analyzing the formation mechanism, it was found that the self-assembly modification of low surface energy material includes both the physical adsorption in hole structure by copper nanoparticles itself and chemical adsorption between carboxyl groups etc and CuO. It shows that the preparation of the copper mesh with special wettability due to surface roughness and chemical composition changes together.Secondly, a new superhydrophilic underwater superoleophobic CuC2O4 mesh with wheat ear-like nanoscale structure was prepared on a Cu(OH)2 mesh with acid-base neutralization method. It was based on the control of concentration of oxalic acid solution and immersion time and its water contact angle is 158.4°. The influence of concentration of the oxalic acid solution and soaking time on the special wettability of CuC2O4 copper mesh and the corrosion resistance of the CuC2O4 mesh were discussed and further compared with the Cu(OH)2 mesh. From analysis by scanning electron microscopy(SEM), X-ray diffraction(XRD) and Fourier transform infrared spectrometer(FTIR), we found that the smooth nanoneedle surface morphology of original Cu(OH)2 brought into rough Cu C2O4 ear of wheat shape, and both change of the chemical composition and surface structure led to the variation of wettability property.Then, the silvering copper mesh of superhydrophilic underwater superoleophobicity was prepared on the copper mesh after pretreatment via chemical deposition technique. We found its underwater oil contact angle is 157.6°. The influence of concentration of the silver nitrate solution and soaking time on the special wettability of silvering copper mesh and the corrosion resistance were discussed. By scanning electron microscopy(SEM) and X-ray diffraction analysis(XRD) characterization techniques, we can see the surface morphology and crystal structure of silvering copper mesh after soaking by appropriate concentration range of silver nitrate solution. We can give a conclusion that the change of chemical composition and improving the surface roughness were the reasons why silvering copper mesh can achieve superhydrophilic underwater superoleophobicity.At last, we tested the performances of copper meshes with special wettability for oil-water separation with cyclohexane, methylene chloride and kerosene etc as the oil phase. At the same time we put forward a collect ship model for solving the huge oil spill. The experimental result showed that these copper meshes with special wettability can achieve high separation efficiency of above 94%, with the static hydrostatic resistance above 1.46 kPa, exhibiting excellent performance of oil-water separation and high hydrostatic resistance. The prepared copper meshes can be applied to separate most of the oil-water mixtures and be recycled for many times, which may provide a good candidate material for solving a wide range of ocean oil spill problems.