Fabrication Of Beta Zeolite Coatings On Stainless Steel Mesh And Their Applications In Oil/Water Separation

The expanding industrial oily wastewater and frequent oil spill accidents not only bring many obstacles to industrial production,but also cause great harm to the environment,which seriously threaten the health of animals and plants and even human beings.The separation of water/oil mixtures is extensively required,exciting the development of facile and efficient oil/water separation technologies.Since oil/water separation is governed by interfacial phenomenon,the use of superwettability to design membranes is an effective and facile method.Under this background,this thesis is devoted to finding inorganic membrane materials with great stability which can be used in water/oil separation.Beta zeolite is a high silicon zeolite that has three-dimensional pore systems with12-rings,and it has excellent chemical stability,thermal stability and mechanical stability.However,the preparation of compact and non-defective beta zeolite membranes is one of the important factors that restrict the research of beta zeolite membranes.In this thesis,we will focus on the synthesis of beta zeolite-coated meshes with regular pore structure and special wettability,and apply them to the field of oil/water separation.This thesis consists of the following two parts:1.Superhydrophilic Al-beta zeolite coatings were synthesized using the secondary growth method on the stainless steel mesh in the alkaline synthetic liquid.And they have been successfully applied to water/oil separation experiments.Water could be separated from water/oil mixtures such as n-hexane,petroleum ether and toluene,and the separation efficiencies were all above 97%.The meshes had good durability and corrosion resistance.It was found that under the H₂O/SiO₂ ratio of 30,Al-beta zeolite coating synthesized for 7 d had better morphology and properties.2.We also prepared the superhydrophobic Si-beta zeolite coating on the stainless steel mesh using the secondary growth method in the fluorine solution.The meshes could separate water from hexane,petroleum ether,toluene and other water/oil mixtures and also had great durability and corrosion resistance.The crystallization time had great influence on the preparation of Si-beta zeolite coating.The superhydrophobic Si-beta zeolite coating synthesized in fluorine sulotion with propyl alcohol for 7 d had better morphology and properties.