摘要
Seawater desalination has become an important method to solve the global fresh water shortage. However, the disposition of concentrated brine was a troublesome problem it was facing because of the environment impact to the ocean. A novel nanofiltration-electrodialysis (NF-ED) hybrid membrane technology to concentrate the brine was proposed and investigated in this paper. And the monovalent-bivalent separation and brine concentration were realized in nanofiltration and electrodialysis separately. Two kind of brine (45100mg/L、 71000mg/L) was investigated. It was shown that all of the SO42- in the brine was rejected in NF, and the recovery ratio of NaCl could be higher than 50%. The concentration of NaCl after comcentrated in a batch ED process could be as high as 159 g/L (brine: 71000mg/L, membrane stack voltage: 15V), and the concentration of other ions was only 5.46 g/L. In a secondary ED concentrating process, the concentration of NaCl could be 174.7 g/L. The influences of membrane stack voltage were also investigated. Both of them has an obviously effects on the concentration and purity of salt solution. The results were shown that the NF-ED process was a feasible brine concentrating process both in economic and technology.