用CARIX工艺去除饮用水中硝酸盐的改进研究

The Study on Regeneration Efficiency of Ion Exchange Resins to Enhance Nitrate Elimination.

针对硬度低而硝酸盐含量高的原水,采用阴离子交换柱研究了用改进型CARⅨ工艺提高对地下水中硝酸盐的去除。除盐过程中,水中硝酸根和硫酸根等阴离子被碳酸氢根离子置换;再生阶段,用二氧化碳和氧化镁粉末,使树脂转变为重碳酸盐型。结果表明,再生时加入氧化镁粉末能明显改善阴树脂的再生效率,最佳投加量为0.45%。本树脂再生后硝酸盐去除率能达到50%以上。

The enhanced nitrate elimination from groundwater by modifications of the CARIX process was described. For raw water with relative low hardness and elevated nitrate concentrations, the process was simplified by applying only an anion exchanger. In the service cycle, sulfate and nitrate species were replaced by bicarbonate species. In the regeneration step, the resin was converted into bicarbonate form by carbonic acid and magnesium oxide. Results of experiments in the laboratory scale have demonstrated that regeneration efficiency is improved apparently by adding magnesium oxide during regeneration. The optimum concentration of magnesium oxide was 0.4%. In this case, all of the resins used in the tests gained the average reduction of nitrate above 50%.