A Study On The Preparation And Oil-water Separation Performance Of PTFE-based Directional Porous Materials

In recent years,the frequent occurrence of oil spills on the sea surface and the massive production of oily sewage have caused the loss of resources and environmental pollution.In order to achieve resource recovery and protect the environment from pollution,oil must be separated from water and recovered.At present,the key to achieve efficient oil-water separation is the preparation of oil-water separation materials.The research and development of new-type efficient oil-water separation materials have attracted much attention.In this paper,three-dimensional separation materials based on polytetrafluoroethylene(PTFE)were prepared and their wetting and separation properties were studied.The main contents are as follows:By using PTFE emulsion,polyvinyl alcohol solution and glass fiber as raw materials,a three-dimensional filtration material with directional pore structures was prepared through a freeze casting method.The microstructure and surface hydrophobic properties of the prepared materials were characterized by scanning electron microscopy(SEM)and contact angle measuring instruments.The oil-water separation performance of the prepared materials was studied by a laboratory-made continuous oil-water separation device.The results show that the prepared material has well defined oriented microchannel structures,which have significant hydrophobic and oleophilic properties,and the contact angle with water is 140°.The material has good mechanical strength and can continuously and efficiently separate oil from oil-water mixture when driven by pressure.Eight oil-water mixtures including diesel-water mixtures were tested and and gasoline-water a separation efficiency of more than 98% has been achieved.By using PTFE emulsion,polyvinyl alcohol solution and metallic fibers as raw materials,a three-dimensional filter material with interconnected porous structure was prepared through a freeze casting method.The surface wettability of the sample can be modified by the applied electric field.The surface hydrophobicity of the prepared material was characterized by the contact angle measuring instrument before and after electrification.The oil-water separation performance of the prepared material was studied by a laboratory-made separation device.The results show that the prepared material has significant hydrophobic and oleophilic properties before electrification,and the contact angle with water is 143°.The hydrophobicity of the sample surface reduces significantly after electrification,and the contact angle with water is 79°.The material has good mechanical strength and can continuously and efficiently separate the oil-in-water emulsified oil under the force of gravity.The cycle test of oil-in-water emulsified oils including diesel oil and peanut oil as oil phase show a separation efficiency of more than 98%.The current work has opened up a new path for the separation of emulsified oils.