Preparation Of Superhydrophilic/air Superoleophobic Coating On Ceramic Substrates And Study On Properties

The harm of oily wastewater and oil leakage to the environment and human health cannot be ignored,so it is urgent to prepare efficient oil-water separation materials to solve the problem of oil-water separation.Superwettable materials are simple to prepare and can effectively separate oil-water mixtures by special surface wettability.Superhydrophilic/air superoleophobic materials have obvious advantages,but the mechanical properties of such modified materials are unstable.Therefore,corresponding strategies are proposed to solve the main problem of poor durability of oil-water separation materials,and the mechanism of action is analyzed.The main research contents and results are as follows:（1）Based on the hydrophilicity of sodium carboxymethyl cellulose（CMC）and the cohesibility of gelatin（G）,we exploried the reaction conditions and proportions of sodium carboxymethyl cellulose and gelatin,the rough structures on the substrate surface and the super hydrophilic/air superoleophobic ceramics were prepared.The coating was analyzed by SEM,EDS,FTIR and ZETA potential.The research shows that the bond between the two can be formed by hydrogen bonding,and the subsequent modification of the super hydrophilic/air superoleophobic properties can be achieved by optimizing the reaction conditions.Under optimal conditions,the OCA in the air of the ceramic is 152.3°,and the water droplets can be completely spread on the surface within 1s.In addition,the coating has a good stability,outdoor exposure for 120 days can still maintain superoleophobic.After7 cycles of use,the separation efficiency of oil and water can be kept above 95%.（2）It is further proposed that the superhydrophilic/air superoleophobic ceramics with better performance are prepared by introducing the hydrophobic protective layer based on CMC/G modified ceramics.By adjusting the concentration of DL411,the hydrophobic layer is added to the hydrophilic layer to solve the problem of poor mechanical properties of the modified material.Under optimal conditions,the WCA was 0°,and the OCA in air was151±1.5°,showing excellent superhydrophilic/air superoleophobic properties.It also has excellent corrosion resistance,mechanical stability and water resistance.In the continuous separation of oil-water mixture,the separation efficiency is up to 99%,and the flux can reach 1.4×10⁴ L m^-2h^-1.After repeated use for 20 times,the separation efficiency of various mixtures of oil and water can reach more than 96%.By comparing the durability and corrosion resistance of materials with and without DL411 layer,the mechanism of adding DL411 layer to the preparation process can improve the durability and mechanical properties of the coating is analyzed.It provides new insights into how to prepare materials with excellent durability.（3）Inspired by the complexation between plant polyphenols and metal ions,a strategy was proposed to construct composite strong intermolecular forces and rough structure to improve durability on the basis of CMC/G modified ceramics by reacting anthocyanins recovered from the waste liquid produced during the cooking of purple potato with metal ions.When the concentration of self-made anthocyanin is 25 g/L,and alternately soaked with Al³⁺for 8 times,and after drying and then in p H=4 environmental conditions for half an hour of acid treatment,plus the subsequent G/C glue and FS50 modification to obtain anthocyanin/ceramic composite membrane,with superhydrophilicity,and the OCA in the air can reach 153°.The sliding angle is less than 8°,and it has oil adhesion resistance.It also has excellent mechanical stability and durability.Moreover,it has high intrusion pressure resistance to all kinds of oil,and can successfully realize the separation of oil and water.In addition,we analyzed the interaction mechanism between anthocyanins and Al³⁺,and the composite rough structure formed by the reaction between the two and the subsequent rough particles played a role in improving the durability of the material.This discovery provides a new direction for the study of anthocyanins and the preparation of durable materials.