亲疏水性CuBTC/PVDF复合膜应用于膜蒸馏抗油实验

采用水热法合成亲水性的CuBTC金属有机骨架(MOFs)颗粒,采用聚乙烯醇(PVA)作为黏合剂,用抽滤的方法将CuBTC颗粒附载在聚偏氟乙烯(PVDF)膜上,之后用戊二醛(GA)对PVA进行交联,制备出表层亲水、底层疏水的CuBTC/PVDF复合膜。通过场发射电子显微镜、比表面积及孔径分析仪、接触角测量仪、孔径分析仪、X射线衍射仪等对CuBTC颗粒和不同CuBTC含量的复合膜的表面特征、结构形态和稳定性进行了表征。结果表明,CuBTC颗粒有着较大的比表面积和孔容,CuBTC颗粒可以牢固地抽滤在PVDF膜表面,热稳定性高且有较好的柔韧性。与抽滤前的PVDF膜相比,随着CuBTC颗粒的增多,膜厚度有所增加,孔径和孔隙率有所减小,但对其膜蒸馏膜通量的影响不大,且在CuBTC含量在0.6 g时表现出较好的性能。在以1 g/L原油和35 g/L氯化钠混合溶液为进料液对原膜和复合膜进行直接接触膜蒸馏抗油污实验,发现原膜很快被油污染堵塞毛孔,而复合膜具有良好的抗油污染能力,可以进行长期的膜蒸馏实验。

Hydrophilic-hydrophobic CuBTC/PVDF composite membrane applied to membrane distillation anti-oil experiment

To solve the problem of water scarcity, membrane distillation(MD) technology has been paid more and more attention to the application of seawater desalination and wastewater treatment, and membrane is an important part of membrane distillation. In the membrane distillation process, the membrane is easily contaminated by oily substances, so it is important to modify the membrane to achieve oil resistance. In this paper, the hydrophilic CuBTC organometallic framework (MOF) particles were synthesized by hydrothermal method. Then, using polyvinyl alcohol (PVA) as binder, CuBTC particles were attached to the membrane by suction filtration. Finally, PVA was crosslinked with glutaraldehyde (GA) to prepare a CuBTC/PVDF composite membrane having a hydrophilic-hydrophobic layer. X-ray diffraction analysis, scanning electron microscopy and specific surface area tests show that CuBTC has high purity, specific morphology and excellent properties. To solve the problem of water solubility of PVA, PVA is crosslinked with glutaraldehyde to cure PVA, and the obtained product has excellent stability. The contact angle, pore size, pore size distribution and porosity of the composite membrane with four different CuBTC contents were analyzed. The results show that CuBTC particles have a large specific surface area and pore volume. CuBTC particles can be firmly suction filtered on the surface of PVDF membrane, which has high thermal stability and good flexibility. The oil-containing high-salt solution prepared with 1 g/L crude oil and 35 g/L sodium chloride was used as the feed liquid to conduct DCMD anti-oil pollution test on the original membrane and the composite membrane. It was found that the original membrane was quickly blocked by oil pollution, and the composite membrane had good resistance, which can be applied to long-term membrane distillation experiments.