Study On The Modified Synthesis Of Metal Organic Framework And Its Liquid Phase Adsorption Performance

With the advantages of simple synthesis,ordered structure,large surface area and high porosity,MOFs is suitable for physical and chemical applications.As more and more MOFs materials are synthesized,the application of MOFs in the field of water treatment has been frequently reported.MOFs was modified with different synthesis methods to synthesize the adsorbent with better adsorption performance and multistage pores.In this paper,two kinds of MOF materials with Zn base as the metal center are selected,namely ZIF-8 and MOF-5.Both materials have large specific surface area and adjustable pore size.Surfactants and rare metals were used to modify the materials.After modification,the pore size of the modified material was enriched with mesoporous and microporous,and the water treatment effect was better.The research contents and results of this project mainly include:1.In surfactant polyethylene glycol(PEG)modification ZIF-8 material,in normal temperature atmospheric pressure methanol solution by adding different molecular weight of PEG(PEG molecular weight from 200-20000,this article selects the molecular weight of PEG 2000 and 6000)to the decoration composite,in liquid medium,as a surfactant PEG in organic membrane is a common additives,is a kind of strong water soluble non-ionic polymer,it can with many high polarity material compatibility,can increase the porosity of membrane and enhance the film hole between themselves.This experiment to explore the PEG on the role of organic-inorganic porous structure,the PEG as soft template agent,to achieve the result of ZIF-8 aperture adjustment,the results show that the synthesized aperture increases the classification of hole,formed the mesoporous aperture of 5-10 nm,and examined the activity of liquid azo dyes wastewater pollutants-brilliant red X-3 b adsorption performance,experiments show that:The adsorption effect of peg-modified zif-8 with a molecular weight of 2000 was enhanced by the presence of its mesoporous cells and the Zeta potential change caused by the addition of the surfactant PEG,which was 26.7% higher than that before the modification.The adsorption capacity was up to 38.5mg/g.2.Cerium(Ce)has excellent adsorption properties for fluoride,and the adsorbents containing cerium(Ce)have higher fluoride adsorption properties than the raw materials.Based on this,the functional adsorbents bearing cerium(Ce)fluoride have become a research focus.Cerium is the most abundant rare earth element,with a variety of industrial and commercial applications,and the presence of cerium ions has been shown to add a positive charge to the surface of the adsorbent,which will help attract negative adsorbents.The influence of cerium doping on the defluoridation performance of organic-metal matrix adsorbent has not been analyzed in detail.Therefore,Ce/ MOF-5 materials with different properties were synthesized by "one-pot method" and "two-step method" respectively.Two different synthesis methods mixed cerium into MOF-5 to synthesize effective materials for water defluorination.The experiments showed that the Ce/ MOF-5 material synthesized by the "one-pot method" adsorbed fluoride ions at p H=7,with a adsorption time of about 60 min and an adsorption balance of 109.6mg·g-1.It conforms to the quasi-second order kinetic model and Freundlich isothermal adsorption model.