Fabrication And Performance Research Of Superhydrophilic/Underwater Superoleophobic Polypropylene Membrane

Water is one of the most vital requirements of living organisms on earth.However,with the continuous development of industrial level,the consumption from people of water resources is increasing,and the water pollution is becoming increasingly serious with the leakage of crude oil and the effluent of oily wastewater.For the water pollution,it is of great significance to develop environment-friendly oil-water separation materials for the solution of water pollution.In recent years,membrane separation materials have provided a novel idea for people to solve this problem.Inspired by the nature,a series of membrane separation materials with superwettability have been developed by chemical grafting and other strategies.However,these methods and means are not suitable for polypropylene materials with chemically inert surface due to the complicated process and troublesome operation.In order to solve these problems,this work intends to introduce the atomic layer deposition technology to achieve a simple control of the superwettability of polypropylene by preparing inorganic nanometer coating on the surface of polypropylene.The following three aspects are covered by the research:?1?The low-cost melt-blown polypropylene non-woven fabric was selected as the base material,and titanium tetraisopropanol was used as the precursor of titanium.The nanometer coating was prepared on the surface of polypropylene fiber through the atomic layer deposition technology,and its microscopic morphology and composition were investigated.Then the wettability were characterized and the underlying mechanism was analyzed.The results showed that based on atomic layer deposition technique,the surface of polypropylene fiber TiO₂ coating with uniform thickness was prepared successfully.After modified by TiO₂,polypropylene fiber has the performance of superhydrophilic/underwater superoleophobic.The mechanism of the performance mainly included following two respects.First,TiO₂nanometer coating surface adsorption of water molecules to cut off oil contact with fiber,sceond,the micro-nano structure can reduce the contact area of oil droplets and fiber effectively based on atomic layer deposition.Under the synergy between them,the surface of polypropylene fibers to achieve the performance of underwater superoleophobic after TiO₂modified.?2?The anti-oil performance of polypropylene non-woven fabric modified by TiO₂ were analyzed,the adhesive force between water and oil of modified nonwoven were explored by interface tensiometer.And the oil resistance of the non-woven fabric modified by TiO₂ were investigated,as well as the chemical resistance were evaluated.The results showed that the adhesive between oil and the polypropylene non-woven fabric with TiO₂ nano coating is extremely low,and the excellent anti-oil performance can make nonwoven to avoid being polluted by different forms of oil.And the modified nonwoven had excellent resistance to chemical character at the same time.?3?The polypropylene microporous filter membrane with better mechanical property were choosen as basic material,which was constructed with the underwater superoleophobic coating.The structure and composition were explored,The surface wettability of the modified membrane were studied.And the oil/water separation efficiency as well as the friction resistance of the modified membrane were explored by the experiment of separation with oil-water mixture,to evaluate stability of/underwater superoleophobic TiO₂ structure built by atomic layer deposition.The results showed that the nano TiO₂ coating with uniform thickness distribution can be constructed on the surface of the inert polypropylene filter membrane through the atomic layer deposition technology,which can improve the roughness of the surface of the polypropylene microporous filter membrane,and realize the transformation of the wettability of the membrane surface from hydrophobic/hydrophilic to superhydrophilic/superhydrophobic.The modified membrane has excellent anti-oil property in water with efficient separation for oil and water mixture.After repeated using for 10 times,the separation efficiency of as-prepared membrane for oil and water can still reach 96.63%.In addition,the membrane has good wear resistance.Even after 20 cycles of friction,the filtration efficiency of the membrane is still more than 98%.In summary,based on the inert polypropylene without modification,the underwater superoleophobic material constructed with TiO₂ coating by atomic layer deposition technique was successfully prepared,which can achieve the transition from hydrophobic/hydrophilic to superhydrophilic/superhydrophobic of the wettability.Meanwhile,the modified polypropylene material demonstrated excellent performance of oil resistance,chemical resistance and the oil/water separation.This research is prospective for the application of polypropylene in oil and water pollution,which may be beneficial to further studies in other fields of wastewater research.