科研之友
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摘要
Nanofiltration(NF) membrane has been developed from the late 1980s and widely applied in the separation of liquid mixtures. Several models for NF process have been proposed, such as the pore model based on the sieving effect, the charge models based on the electrostatic effect, and the electrostatic steric-hindrance model and the Donnan steric pore model based on the both effects, which play an important role in understanding the separation mechanism and promoting the application of NF. However, the performances of these NF membranes with features of "loose RO membranes" cannot be predicted by commercial RO simulation software, which is a severe restriction on straightforward implementation of large-scale NF applications. In regard to these problems, a model was proposed for the separation performance of mixed salts solution across NF membranes to promote the application of NF during the water treatment in the light of the competitive effect among co-ions and regulation effect among counter-ions. Both two effects can be determined by some specific experiments. Recently, based on the indepth experimental studies on rejection performance and the attendant electrokinetic properties, some researchers have found that the performance of NF membranes cannot be predicted completely by merely considering the sieving and electrostatic effect, but some drawbacks still exist in the analysis of electrokinetic properties. The further studies have contributed to a deeper understanding on the particular effect caused by the nano-scale pore size and charge features caused by the complicated interaction in solution. Moreover, the dielectric effect in the transport process of ions through NF membranes has been addressed and quantitatively analyzed.
- 出版日期2012-5-24
- 单位清华大学
