Study On The Synthesis And Application Of UiO-66-NH₂

Metal-organic frameworks?MOFs?are a series of emerging materials developed in recent decades,which consist of metallic nodes joined in an ordered fashion by organic linker molecules to generate a 3-D porous crystal compound.Due to their specific nature including permanent porosity,high crystallinity,high surface areas,excellent tunability of pore size,crystal shape,and functionality,they are extensively investigated in a wide variety of potential applications in gas adsorption and storage,catalysis,drug delivery,sensors etc.However,the applications of the most existing MOFs materials in industry are limited for their low stability.Indeed,to bring MOFs into an industrial application,on the one hand,their stability must be improved;on the other hand,a vigorous road has to be developed for the reliable and cost-effective synthesis of MOFs?Attributing to the high hydrothermal and chemical stability of UiO-66,especially its high resistance towards humidity,UiO-66 has been drawn much interest for many practical applications in liquid separation and gas separation.This work is a systematic investigation of the microwave-assisted synthesis of UiO-66-NH₂.In a detailed study,the influence of microwave irradiation time,temperature,and modulator concentrations on morphology,crystallinity and stability of UiO-66-NH₂ is investigated with the aim to develop a reliable and reproducible strategy for the preparation of well-shaped UiO-66-NH₂.Then the microwave assisted synthesized UiO-66-NH₂ was test under 273 K and 298 K condition for CO₂ capture.The preparation process of Ui O-66-NH₂ membrane was investigated,and the membrane was tested by pervaporation.The specific work of this paper is as follows:?1?Solvothermal and microwave assisted heating method were applied for the preparation of UiO-66 and Ui O-66-NH₂.Zirconium chloride acts as the metal source,terephthalic acid/2-aminoterephthalic acid acts as ligand,and HAc and HCl were used as modulators in different concentrations.The powers?UiO-66-NH₂?were obtained after the reaction under specific temperature.?2?The resulting UiO-66-NH₂ was characterized by Fourier transform infrared?FT-IR?,PXRD,FESEM,TGA,and BET.From the analysis of the morphology,crystallinity and the adsorption properties,we could identify optimal conditions for the microwave synthesis of UiO-66-NH₂.The gas absorption and desorption test of the obtained product shows that UiO-66-NH2 has good application value in CO₂capture.?3?Well-intergrown UiO-66-NH₂ membranes could be prepared through a repeated synthesis method on the APTES-modified macroporous Al₂O₃ tubes by in-situ solvothermal method.The UiO-66-NH₂ can be synthesized rapidly in 30 min by microwave heating.Due to the presence of–NH₂ groups,CO₂ is preferentially adsorbed?5.8 mmol/g at 273K and 1 bar?.Due to the high quality of UiO-66-NH₂ prepared by microwave-assisted synthesis,an adsorption selectivity CO₂/N₂ of 66 is determined for a simulated post-combustion gas at 298 K.The developed UiO-66-NH₂ membranes were evaluated for 3.5 wt%seawater desalination by pervaporation.It is found that the UiO-66-NH₂ membranes show high desalination performances,and ions rejections of348 K are above 99.7%.