Preparation Of MOFs Materials And Application In Water Treatment

Water pollution has become a serious problem,posing a threat to the environment and human health.Among them,there are many toxic organic and inorganic substances in printing and dyeing wastewater,and the color is deep.Emulsified oil in oily wastewater is one of the most difficult to handle,so an effective and simple treatment method is needed.Because metal-organic frameworks(MOFs)are easy to synthesize,have large specific surface area,low energy consumption for separation mixtures,and adjustable pore channels,they have been widely used in recent years.This thesis focuses on two mixed systems that simulate the properties of industrial wastewater.UiO-66 and ZIF-8 are two special new types of metal-organic framework materials with special physical and chemical properties.Two separation materials with different functions are designed,and separation performance tests are performed on different mixed systems that simulate the properties of industrial wastewater.The main research contents are as follows:1.In this study,we use the solvothermal method to synthesize UiO-66 crystals with different particle size and uniformity by varying the amount of the modulators.Along with the increase of modulators,the UiO-66 crystals enlarged,and became uniform.200 nm UiO-66 had the best perfomance on Congo red adsorption,with a maximum adsorption amount of 91.41 mg g-1.By analyzing the data of congo red adsorption,the adsorption fitted the pseudo second kinetics model and Langmuir adsorption isotherm,indicating that it was a chemisoption.Owing to ?-? stacking effect between benzene ring of terephthalic acid in UiO-66 and the benzene ring in Congo red,and electrostatic interaction,congo red was adsorded on the surface of UiO-66.UiO-66/cellulose acetate composite membrane was prepared by vacuum suction filtration method,and its rejection ratio of congo red in congo red solution was?94%.This work lays a found to synthesis adsorption materials for high-efficiency dyes adsorption.2.Surfactant-stabilized oil-water emulsions are especially difficult pollutants to eliminate.Membrane technology has been extensively applied for oily water treatment.However,the immutable wettability limits its application of separating different types of emulsions.In this work,novel zeolitic imidazolate framework-8(ZIF-8)film-coated stainless-steel meshes with switchable superlyophobicity were fabricated for all types of emulsions separation.The membrane exhibited outstanding superoleophobicity(161°)and superhydrophobicity(153°).By switching superlyophobicity through prewetting process,the membrane could selectively remove oil droplets in surfactant-stabilized oil-in-water emulsion via superoelophobicity and water droplets in surfactant-stabilized water-in-oil emulsion via superhydrophobicity.Upon further modification of the membrane by polyvinyl alcohol,high-flux emulsion separation was achieved.This work provides a foundation for the development of MOFs membranes for selective emulsion separations with high-flux.