Synthesis And Application Of Kaolinite Modified Melamine Sponge For Oil-water Separation

Recently,the rapid development of modern industrialization inevitably released various oils and organic solvents leakage,which gave rise to a severe influence to environment and ecology.Adsorption is regarded as the most important method to remove oils and organic solvents from water surface because of its convenient operation and low-cost.The idea adsorbent should possess high adsorption capacity,super hydrophobicity,low cost and excellent recyclability.The traditional adsorbents generally have drawbacks including low adsorption capacity,poor recyclability and wettability,thereby limiting their practical application.Recent years,sponge adsorbents have aroused considerable interest in the field of oil-water separation due to their low density,good flexibility,high porosity,and three dimensional skeleton structure.However,melamine sponge(MS)is naturally hydrophilic and oleophilic,which restricts the separation of oils and organic solvents from water.Thus,modifications are necessary to transform the hydrophilic-oleophilic sponge surface to hydrophobic-oleophilic surface.In our work,kaolinite modified melamine sponge(KMS)and kaolinite modified graphene oxide-melamine sponge(K-GOMS)were prepared,in which melamine sponge was serve as template,graphene oxide and kaolinite were used to modify the raw sponge,and their adsorption performance for oils and organic solvents was studied.It is believed that this study can provide a novel and practical methodology for further constructing facile,low-cost,and high quality superhydrophobic adsorbents for oil spill treatment in environment.The results showed that both modified sponges possessed oleophilicsuperhydrophobic property,the water contact angles of K-MS and K-GOMS reached 156.5° and 152.3°,respectively.The K-MS and K-GOMS exhibited not only superior adsorption capacity for various organic solvents and oils,45~85 and 50~113 g/g,respectively,but also outstanding recyclability with an adsorption capacity retention higher than 92% and 94% after 30 cycles of diesel oil adsorption,90% and 96% of after 30 cycles DMF adsorption,and excellent environmental tolerance in wide range of pH values and temperatures.In a word,all of these remarkable performances enable K-MS and K-GOMS great potential in the removal of organic solvents and oils from water and a promising candidate for practical treatment of oil spillage and chemical leakage.