Fabrication Of Superhydrophbicand Superoleophilic Polyurethane Sponge And Its Application In Oil/Water Separation

In recent years,because of more frequently occurring oil spill and oily waste water produced by human beings in daily life,there is an increasing demand for efficient selective separation materials to deal with water pollution.Due to its high oil-water separation efficiency,biomimetic interface oil-water separation materials with special wettability have attracted extensive attention.However,the existing biomimetic interface oil-water separation materials still have some problems in the preparation process and its properties,such as complicated preparation process,high cost,the use of harmful chemical reagents in the preparation process,low coating coverage and low adhesion between coating and substrate,poor performance,and so on.Aiming to solve these problems,in this study,the superhydrophobic and superoleophilic polyurethane sponges with high durability,selectivity for oil-water separation and reusability was prepared by the simple,efficient and environment friendly methods.In this study,commercial polyurethane sponge with the pore size of 350 μm was modified via the simple solvothermal method and chemical vapor deposition method.Then a thickly superhydrophobic ZnO coating was coated onto the surface of polyurethane sponge and the superhydrophobic nano ZnO polyurethane sponge was successfully prepared.The result showed that the as-prepared sponge possessed excellent superhydrophobicity and superoleophilicity.The resulted sponge exhibited a high water contact angle of 160° and the oil droplet was adsorbed within two seconds.The resulted sponge exhibited a high oil-absorption capacity for various oils and organic solvent and showed oil-adsorption capacity up to 25 times of its own weight.The result also showed that the prepared oil-water separation material had excellent oil-water separation performance.Due to its good adhesion between the coating and sponge,the as-prepared sponge showed high durability and the material still maintained excellent superhydrophobicity after ultrasonication in acetone and n-hexane for 9 hours.In addition,we also found that the oil-water separation material could resisted acid and alkali attacks and have good reusability,the materials still had excellent superhydrophobicity and superoleophilicity after repeated absorption-desorption processes for 200 cycles.Moreover,the resulted sponge could degraded toxic methylene blue under ultraviolet light irradiation.Aiming to solve the limitation of the solvothermal method that can not realize large-lot production,the superhydrophobic polysiloxane/polyurethane sponge was fabricated through a solution immersion method.This method is the improvement of the existing method.After improvement,the preparation process had the advantages of economy,high efficiency,environmentally friendly and could realized large-scale preparation.The superhydrophobic polysiloxane/polyurethane sponge possessed excellent superhydrophobicity and superoleophilicity and exhibited a high water contact angle of 152° and the oil droplet was adsorbed within few second.The resulted sponge exhibited a high oil-absorption capacity for various oils and organic solvent and showed oil-adsorption capacities up to 30~35 times of its own weight.In addition,we also found that the superhydrophobic sponge could resisted acid and alkali attacks and had good reusability,the materials still had excellent superhydrophobicity and superoleophilicity after floating them on the solutions of pH1-13 for 24 hours and could be repeated absorption-desorption processes for 80 cycles.