Study On Structure Regulation Of Zr-MOF And Efficient Adsorption Of Cr(Ⅵ)

The rapid pace of urbanization and the further industrialize have rapidly accelerated the emission and diffusion of man-made heavy metal pollutants,which will constitute a grave harmful toaquatic organisms and human ecological environment.In particular,Cr（Ⅵ）elements in wastewater can cause great harm to the environment and human body due to their strong toxicity and carcinogenic nature.Adsorption technique is considered the best technique for the removal of heavy metals,while metal-organic frame materials are considered very promising emerging adsorbents due to their rich active sites and their surface chemical harmonic and high specific surface area.In this paper,UiO-66 has investigated the effects of acid regulator species,benzoic acid concentration,zirconium source and ligand concentration,and functional ligand content on the defective regulation and performance of UiO-66 powder.UiO-66-NH₂ was then used for the efficient selective adsorption of Cr（Ⅵ）,and the optimal adsorption conditions and adsorption mechanism were studied.Finally,UiO-66-NH₂ is combined with the alumina ceramic film,and it is used for the adsorption and interception of Cr（Ⅵ）in water treatment applications.The specific research contents are as follows:Firstly,UiO-66 was prepared by solvent heat,the effects of hydrochloric acid,acetic acid and benzoic acid on the crystal structure,morphology and pore regulation of UiO-66,the results found that the same molar regulator,benzoic acid contains more hydrogen bonds to accelerate the formation of the ligand,making the regulation performance is better than the hydrochloric acid and acetic acid,the crystal size about 70nm,and the specific surface area is as high as 1439.74m²·g^-1.Based on this analysis,the effects of different concentrations of benzoic acid,zirconium source and ligand concentrations,triethylamine concentration and amino-functionalized ligands on the structure and performance of UiO-66 were explored.The results show that the structure and performance of MOF are better when the concentration of zirconium source 50;when the concentration of triethylamine is zirconium source 1,the co-adjustment with benzoic acid can stabilize the grain size at about 100nm.Functionalization of the ligand increased the activity of UiO-66,and the crystal structure of UiO-66 was further optimized to explore the influence of the content of the amino functionalized ligand on the structure and performance,and found that the structure and performance of UiO-66-NH₂ were better when the ligand and zirconium source were 1:1.Secondly,UiO-66-NH₂ is applied to the adsorption of Cr（Ⅵ）in water,Because of its excellent electron supply capacity and affinity for anion amino group,it has high efficiency adsorption capacity of Cr（Ⅵ）,and the unit adsorption amount is 305.16mg·g^-1.By studying the adsorbent content,temperature,initial concentration,p H value and selectivity,we show that the material has good adsorption effect at p H=2,100mg/L and 30℃,the maximum saturated adsorption amount of Langmuir is up to 610mg·g^-1,and UiO-66-NH₂still has a high removal rate of Cr（Ⅵ）under the common anion competition.Finally,Zr O₂ sol was prepared by sol-gel method,and alumina powder was added to form the Zr O₂@Al₂O₃ structure,and the separation layer was prepared by impregnated extraction.By exploring the effect of the concentration of zirconium sol on the wrapping state and the thickness of the separation layer,it was found that when the concentration of zirconium sol was 1 mol/L,the separation layer was 5.2μm thick and closely bound to the carrier.The ceramic membrane was synthesized by homologous metal induction,crystal growth and secondary growth to compare the removal capacity of Cr（Ⅵ）.The results show that the MOF membrane synthesized by the secondary growth method has more loaded MOF crystals,so the removal rate of Cr（Ⅵ）is higher.