二级反渗透技术制备高纯水工艺研究

Study on preparation of ultrapure water with double-pass reverse osmosis technology

分析了二级反渗透系统制备高纯水工艺中二级系统进水pH值、CO2含量及膜类型的配置对脱盐率的影响,总结了进水电导率与脱盐率的关系.试验研究表明:以引黄入津的水为特定原水,二级系统进水pH值对脱盐率影响较大,pH值在7.5左右时脱盐率最高,淡水电导率可达到0.15μS/cm(6.7MΩ·cm);由于进水CO2含量较低,脱盐率几乎不受其影响;表面带负电荷ESPA4型膜的脱盐率高于带正电荷的LFC2型膜.

The effects of the feedwater pH of double-pass reverse osmosis system, the concentration of carbon dioxide and the dispositions of RO membrane models on the desalination rate in the technology are studied and analysed.And the relationship between the conductivity of feedwater and desalination rate is given.The test shows that,on the condition of the particular feedwater, the feedwater pH of the double-pass reverse osmosis has a great effect on the desalination rate. When the pH is about 7.5, the desalination rate is highest, and the conductivity of plain water achieves 0.15 μS/cm(viz.6.7 MΩ·cm).Since the percentage content of the carbon dioxide of feedwater is low, the desalination rate is hardly affected by it. The desalination rate of ESPA4 with the negative electricity on the surface is higher than that of LFC2 with the positive one.