Preparation And Properties Of Fiber-based Porous Ceramics For Oil-Water Separation

With the rapid development of metallurgical industry,it not only brings good economic benefits to the society,but also pollutes the environment.The typical one is the large amount of oily wastewater produced in the metallurgical industry,which mainly comes from the cooling water and flushing water used in the metallurgical equipment,as well as the added lubricants and oil leakage generated by the operation of the equipment.The treatment of these oily wastewater is of great significance to solve the problems of environmental protection and lack of water resources.The purpose of this paper is to prepare a kind of environmental protection and energy-saving porous ceramic material which can effectively separate different kinds of oil-bearing wastewater.Inspired by bionics and based on the theory of special wettability,two kinds of mullite fiber-based porous ceramic materials with different wettability were prepared and their oil-water separation performance was studied.The main research contents and conclusions are as follows:(1)Mullite fiber based porous ceramic materials were prepared by water based gel casting with mullite fiber as skeleton and alumina and kaolin powder.The effects of mullite addition on bulk density,porosity and compressive strength of the material were studied.The results showed that with the increase of mullite fiber mass percentage,the bulk density of porous ceramic materials decreased,the porosity increased and the compressive strength decreased.Based on the experimental results of water contact angle and the properties of porous ceramics,the sample with 66%of fiber mass was selected as the base material for the follow-up study.Its bulk density was 0.69g/cm3,porosity was 75.6%,and compressive strength was 1.13MPa.(2)Taking 66%mullite fiber as the matrix material and dopamine as the binder,the octadecylamine with low surface energy was grafted onto the surface and pore of the porous material to obtain the coating.After coating,the unit mass pore area of the material increased from 0.08m2/g to 0.21m2/g,and the average pore diameter decreased from 39.9μm to 21.0μm.The coating made the porous material hydrophobic and lipophilic.It is found that porous ceramic material can absorb the oil in oil-water mixture into the material in a short time,so as to achieve the effect of oil-water separation.The material can absorb up to 1-2 times of its own mass of oil.The oil retention performance of the material is good,and the performance of repeated experiments of the material has little change,showing excellent reusability.(3)Taking 66%mullite fiber as the matrix material and dopamine as the binder,the high surface energy polyethylene polyamine was grafted into the surface and pore of the matrix material to obtain the coating.After coating,the unit mass pore area of the material increased from 0.08m2/g to 0.20m2/g,and the average pore diameter decreased from 39.9μm to 20.4μm The coating made the porous material hydrophilic underwater hydrophobic oil properties.It is found that the porous ceramic material after treatment is cut into thin sections for use as a filter membrane,and only water can pass through the oil-water mixture when it passes through,so as to achieve the effect of oil-water separation.The oil-water separation process of the material does not need external force,and the separation effect is excellent,and the effect of repeated use is almost unchanged.