纳滤去除水中的有害离子

本文综述了纳滤去除饮用水和重金属废水中的有毒有害离子的应用研究，阐述了纳滤膜对无机盐的截留效果主要取决于膜对离子的电荷效应，表现在对多价离子的截留率高于单价离子。利用纳滤膜这种分离性能，可以去除部分饮用水中微量的有害单价离子（如NO2^-、NO3^-、F^-等）和大部分的有毒二价离子（如HAsO4^2-和重金属离子），获取优质安全的饮用水；也可以用于处理重金属废水，能有效去除废水中的重金属离子。将纳滤和反渗透集成用于重金属废水处理，可以做到对有毒重金属离子的回收利用和出水回用，实现清洁生产，既具经济效益，又具环境效益，在工程实际中极具推广应用价值。

REMOVAL OF TOXIC OR HARMFUL IONS FROM WATER OR WASTEWATER BY NANOFILTRATION

The removal of toxic or harmful ions from water or wastewater by nanofiltration was reviewed. The ions retention by nanofiltration mainly attributes to electrostatic effect and sieve effect. Therefore, the retention for bivalent ions are higher than that for monovalent ions. According to this separation mechanism, monovalent inorganic pollutants such as nitrite, nitrate and fluorides could be partly removed from water and bivalent ions such as HAsO4^2- and heavy metals could be effectively removed, so safe drinking water can be produced. In addition, heavy metals could also be effectively removed from wastewater by nanofiltration membranes. The reuse of heavy metals and effluent could be realized if the combined process of nanofiltration and reverse osmosis treated electroplating wastewater. This process could be widely applied in practice because of its economic and environmental value.