| With the rapid development of industry,energy and environmental issues have attracted more and more attention.Traditional gas separation and purification technology has high energy consumption and high cost.Industrial wastewater contains a lot of harmful substances,and direct discharge will seriously damage the environment.Therefore,researchers look forward to developing a potential porous material for effective gas adsorption and the adsorption of hazardous substances in wastewater.Metal-organic frameworks(MOFs)are a new type of porous material composed of metal ions or metal clusters and organic ligands.As a new type of porous material,MOFs can achieve accurate adjustment and functionalization of pore structure.Compared with traditional molecular sieve,these unique properties make MOFs show great application prospects in the field of adsorption and separation.Therefore,MOFs can be used as a potential porous material for gas adsorption and the adsorption of harmful substances in wastewater.Based on this,this paper mainly studied the performance of MOFs constructed by thiophene dicarboxylic acid and triazole ligands in gas adsorption and dyes adsorption.The specific research contents are as follows:1.Three three-dimensional porous metal-organic frameworks[Zn2(DMTDC)(tz)2]·DMF·2H2O(1),[(CH3)2NH2][Zn2(DMTDC)2(tz)]·3DMF·5H2O(2)and[(CH3)2NH2][Zn2(DMTDC)2(3-mtz)]·4DMF·3H2O(3)were synthesized under solvothermal conditions using thiophene dicarboxylic acid(3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid,H2DMTDC)and triazole derivatives(1,2,4-triazole=tz,4-amino-4H-1,2,4-triazole=4-atz,3-methyl-3H-1,2,4-triazole=3-mtz).The tz ligand in compound 2 was formed by 4-atz taking off an amino group under solvothermal conditions.Gas adsorption experiments show that different triazole ligands had different gas adsorption properties.Compounds 1 and 2 can adsorb CO2 at195 K,but cannot adsorb N2 at 77 K.The adsorption of 3 for N2 at 77 K and CO2 at195 K show type I isotherms,and 3 can selectively adsorb CO2 over N2 at room temperature.The isosteric heat of adsorption calculated by virial equation is 28.7 k J mol-1.2.Three novel three-dimensional porous metal-organic frameworks[(CH3)2NH2][Zn2(DMTDC)2(dmtz)]·5DMF(DMF=N,N-Dimethylformamide)(4),[Zn2(DMTDC)1.5(dmtz)]·4DMA·2H2O(DMA=N,N-Dimethylformamide)(5),[Zn2(DMTDC)1.5(dmtz)(H2O)1.5]·3DEF·5H2O(DEF=N,N-Diethylformamide)(6)were synthesized by H2DMTDC and 3,5-dimethyl-1H-1,2,4-triazole(3,5-dimethyl-1H-1,2,4-triazole,dmtz)in different solvents.Single-crystal X-ray diffraction results show that the frameworks have the same ligand building units,and different guest molecules exist in the pores.Gas adsorption tests show that compounds 4-6 display different adsorption properties for C1(CO2?CH4)and C2(C2H2?C2H4?C2H6)gases.Compound 4 has a good selectivity for gases,and when the molar ratio of two gases was 50:50 at 298 K,the IAST selectivity of C2H6/CH4,C2H4/CH4,C2H2/CH4,C2H2/CO2 and C2H6/C2H4 is 24.0,11.7,9.5,3.2 and 1.6,respectively.3.A new anionic metal-organic framework[(CH3)2NH2][Zn3(DMTDC)2(dmtz)(OH)2]·5DMF·2H2O(7)was obtained by changing the ratio of reactants using thiophene dicarboxylic acid H2DMTDC and 3,5-dimethyl-1H-1,2,4-triazole(dmtz).The properties of dyes adsorption for compounds 4 and 7 were studied.The results of dyes adsorption show that compounds 4 and 7 can selectively adsorb cationic dyes over neutral and anionic dyes.Due to its size effect,compound 4 can selectively adsorb smaller cationic dyes.This study indicates that compounds 4 and 7 can be used as potential adsorbents for cationic dye. |
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