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在空气除湿过程中,膜液体分离技术凭借其对空气无污染、效率高、能耗少等优点,已越来越得到人们的重视。但是在长期的使用过程中,经常发现液体会泄漏到气体中。为了解决这一问题,通过对聚偏氟乙烯(PVDF)膜进行改性,使其表面有一层薄薄的α,β-二羟基聚二甲基硅氧烷(PDMS)致密层。采用扫描电镜、接触角测量表征改性前后的膜结构变化,并实验测出PVDF膜改性后的除湿效率、水蒸汽渗透速率和总传质系数。结果表明,PVDF膜改性后的除湿效率,水蒸汽渗透速率和总传质系数都有所下降,但其接触角由69°提高到120°以上,膜表面有一层致密的PDMS皮层,长期使用能有效的防止膜的泄漏问题。
In the air dehumidification process, membrane liquid separation technology has drawn more and more attention due to its advantages of air pollution, high efficiency and low energy consumption. However, in the long-term use, it is often found that liquid leaks into the gas. In order to solve this problem, polyvinylidene fluoride (PVDF) membrane was modified to have a thin layer of α, β-dihydroxy polydimethylsiloxane (PDMS) dense layer on the surface. The changes of membrane structure before and after modification were characterized by scanning electron microscopy and contact angle measurement, and the dehumidification efficiency, water vapor transmission rate and total mass transfer coefficient were measured experimentally. The results showed that the dehumidification efficiency, water vapor transmission rate and total mass transfer coefficient decreased after the modification of PVDF membrane, but the contact angle increased from 69 ° to above 120 °. The surface of the membrane had a dense layer of PDMS, which was used for a long time Can effectively prevent membrane leakage problems.