The Preparation Of Metal-organic Framework/Macroporous Resin Composite Materials And Their Research On The Removal Of Typical Environmental

Dyestuffs and drugs are widely used in industry and medical industries,resulting in a sharp increase in their content in water,which seriously threatens the water environment and human health.Therefore,an efficient and simple water treatment technology is urgently needed to solve this problem.MOFs(metal-organic frameworks material)have shown great potential in the field of pollutant adsorption due to their ultra-high specific surface area,tunable pore size,and easily modified pore surface.However,MOFs have the limitations of difficult solid-liquid separation and instability in the aqueous phase in practical water treatment applications.In view of the shortcomings of MOF in the adsorption process,taking D201macroporous anion exchange resin with high chemical and hydrodynamic stability as the carrier,three new MOF/D201 composite adsorbents with high adsorption properties were prepared by in-situ synthesis with different MOFs by hydrothermal synthesis method,and adsorbed diclofenac sodium(DCF)and Acid Orange 7(AO7)in water.The main research contents and results are as follows:(1)Firstly,MIL-101(Fe)/D201,MIL-88A/D201 and HKUST-1/D201 composites were prepared by hydrothermal synthesis.Through XRD and FTIR tests,it was found that MIL-101(Fe)/D201,MIL-88A/D201 and HKUST-1/D201 appeared main characteristic peaks corresponding to their respective single MOFs,indicating that the composite adsorbents were initially synthesized successfully.The microscopic morphologies of the three composite materials were observed and analyzed by SEM test,and it was found that the addition of D201 macroporous resin did not destroy the original structure of MOF.Compared with single MOF,the dispersion of MOF in D201 macroporous resin is improved and the particle size is smaller.The nitrogen adsorption-desorption data show that all three composite adsorbents have high nitrogen saturation adsorption capacity.By BET analysis,it was found that the BET surface areas of the three MOF/D201 composites were all greater than 250 m^2/g.It can also be seen that MIL-101(Fe)/D201 and HKUST-1/D201 are porous materials with micropores and macropores,and MIL-88A/D201 is a porous material with mesopores and macropores.(2)Under different adsorption factors,the adsorption capacity of MOF/D201composite and single MOF was compared.It was found that the adsorption capacity of MOF/D201 composite was higher than that of single MOF.The optimum addition amount of MIL-101(Fe)/D201 in 50 m L of DCF(80 mg/L)was 0.5 g/L,and the removal rate was as high as 98.3%.The optimum dosages of MIL-88A/D201 and HKUST-1/D201 in 50 m L of AO7(100 mg/L)were 0.5 g/L and 0.4 g/L,respectively,and the removal rates were as high as 94.6%and 90.4%,respectively.It is found by experiments that the temperature rise and acidic conditions are more conducive to the adsorption of DCF and AO7 by MOF/D201 adsorbent,and the type and concentration of interfering ions have little effect on the adsorption.(3)The adsorption processes of MIL-101(Fe)/D201,MIL-88A/D201 and HKUST-1/D201 all followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm model.The adsorption thermodynamic model indicated that the adsorption of MIL-101(Fe)/D201,MIL-88A/D201 and HKUST-1/D201 were all spontaneous,endothermic and entropy-increasing processes.(4)After 6 adsorption regeneration experiments,MIL-101(Fe)/D201,MIL-88A/D201 and HKUST-1/D201 still maintained high removal rates,indicating that the prepared MOF/D201 adsorbent had excellent regenerability usability.