纳滤膜盐水溶液软化过程中膜面动态结垢机理研究进展

膜面结垢是纳滤(NF)膜盐水溶液软化过程中遇到的最主要问题之一。尽管已有大量的研究者对NF膜面结垢趋势预测和膜面污染物形貌的先进科学表征进行了深入广泛的研究,但对NF膜面动态结垢机制和过程还没有系统的报道。本文详细描述了包括膜阻力、浓差极化阻力、滤饼层阻力和膜孔堵塞阻力在内的NF膜结垢阻力理论模型;综述了包括膜面浓差极化、构晶离子成核和膜面结晶沉淀的NF膜面动态结垢过程的研究进展,重点阐述了表面结晶和主体结晶两种NF膜面结晶生长机制的研究概况,并展望了NF膜面结垢机理的研究前景。

Research Progress on Dynamic Scaling Mechanism on Nanofiltration Membrane Surface for Saline Water Softening

Membrane scaling is regarded as one of the key-problems for nanofiltration(NF) membrane separating performance during salt solution softening process. Most of the studies on NF membrane inorganic fouling were performed to comprehensively investigate the running conditions(such as NF permeate recovery and recycling ratio) on the scaling potential prediction and apply different techniques to characterize the NF membrane scaling morphology. However, only a few information was reported systematically about the mechanisms and processes of NF membrane surface dynamic scaling. The fundamental mechanisms and processes referred to sparing soluble precipitations and scaling are not cleared clarified. This paper focuses on the research progress for the mainly NF membrane scaling mechanisms(including crystallization and particulate fouling, bulk crystallization and surface crystallization), which play critical roles during scale formation on NF membrane surface. Besides, it is introduced in detail for the resistance(including membrane resistance, concentration polarization resistance, cake resistance and pore-block resistance) models used to quantify NF membrane inorganic fouling. In addition, the scaling processes including concentration polarization stage, nucleation stage, crystallization and deposition stage, respectively, on the NF membrane surface are introduced briefly. Finally, the further development as well as challenges on dynamic scaling mechanism on NF membrane surface for saline water softening are suggested.