| LI Yan-qiu,TANG Yi,PENG Yin-yin,LI Hong-jiang,LIU Lei,LIU De-rong,XIONG Wei,LIU Ning,YUAN Guo-yuan.Preparation of MOFs Mixed Matrix Membrane and Its Separation Effect on Co(Ⅱ)[J],52(6):410-419, 438 |
| Preparation of MOFs Mixed Matrix Membrane and Its Separation Effect on Co(Ⅱ) |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.06.038 |
| KeyWord:UiO-66 PAN mixed matrix membranes Co(Ⅱ) separation |
| Author | Institution |
| LI Yan-qiu |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| TANG Yi |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| PENG Yin-yin |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| LI Hong-jiang |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| LIU Lei |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| LIU De-rong |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| XIONG Wei |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China |
| LIU Ning |
Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu , China |
| YUAN Guo-yuan |
College of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing , China;Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu , China |
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| Abstract: |
| Membrane separation method is considered as one of the methods with great potential for industrial application because of its advantages such as simple operation, energy saving and environmental protection, high efficiency and flexibility, small equipment footprint and scale-up ability of production. Therefore, the membrane separation method is used to separate cobalt ions. The work aims to solve the problem that MOFs raw materials are expensive and adsorbent is not easy to recover. Waste polyethylene terephthalate (PET) bottles are used as acid source to prepare UiO-66, and UiO-66 is doped into polyacrylonitrile to prepare MOFs mixed matrix membranes (MMMs), so as to improve the separation performance of the membrane material for cobalt ions. The synthesis process of the MMMs was divided into the following steps. Firstly, terephthalic acid was obtained by depolymerization of PET bottles. Then, the terephthalic acid was used as ligand to prepare zirconium-based MOFs UiO-66. Finally, combined with the good compatibility between MOFs and polymer, different contents of UiO-66 were dispersed into the polyacrylonitrile matrix, and UiO-66-PAN MMMs were prepared by solvent evaporation. Using waste PET bottles as acid source could not only reduce the cost of materials, but also turn waste into treasure, and realize the secondary utilization of resources. UiO-66 and UiO-66-PAN were characterized by XRD, FT-IR, BET and SEM, which proved that the material was successfully prepared and the addition of UiO-66 enhanced the thermal and mechanical stability of the membrane material. When the doping content of UiO-66 increased from 0% to 6%, the specific surface area of the membrane increased with the increasing content of UiO-66. As the doping content of UiO-66 continued to increase to 8%, UiO-66 showed obvious aggregation phenomenon, blocking the pore structure of the material and resulting in a significant decrease in membrane flux and rejection. Among all the materials, the best performance was achieved when the doping content was 6%, and the membrane flux and interception rate of the material were higher than those of other materials, reaching 2 654 L.m–2.h–1 and 49.71%, respectively. UiO-66-PAN was used for the separation of cobalt ions. When pH value was 8.3 and temperature was 25 ℃, the maximum adsorption capacity of 6%-UiO-66-PAN reached 26.56 mg/g. The separation of materials was a spontaneous endothermic process. By fitting the data, the material was more consistent with the quasi-second-order kinetic model and Freundlich adsorption isothermal model. It was found that the removal rate of cobalt ions remained above 80% after five cycles of experiment. UiO-66-PAN had good mechanical strength and stability. Finally, Co2+ adsorption mechanisms were discussed based on microstructure analysis and adsorption kinetics and isotherms, the result showed that chemical adsorption was the main adsorption method, and the formation of Co2+ and —COOH complex dominated the cobalt adsorption process. The experimental conclusion shows that the dispersion of UiO-66 in polymer matrix enhances both the separation performance of cobalt ions and the stability of the membrane and flux of the membrane. Besides, the addition of UiO-66 can enhance the adsorption capacity of membrane materials for Co(Ⅱ), and the porous MOFs can enhance the separation performance of mixed matrix membranes for metal ions, which has potential application value in the separation of metal ions. |
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