脱除脱盐废水中钙镁离子的研究

Study on removal of calcium and magnesium ions in desalination wastewater

工业中的脱盐废水具有较高的硬度,采用化学法与吸附法对体系中镁离子、钙离子的脱除情况进行了研究。首先,采用氧化钙水溶液沉淀废水中的镁离子;其次,向脱除镁离子的滤液中加入沸石,吸附除去钙离子。此外,进行了二氧化碳法脱除钙离子这一具有环保意义的试验。研究结果表明:氧化钙水溶液中的钙离子与废水中镁离子的物质的量比为7∶1时,镁离子脱除效果较好;无需向体系中加入p H值调节剂;在处理200 m L滤液时,2 g沸石、16 h振荡时间使钙离子的沉淀率达到100%。二氧化碳对钙离子的脱除具有一定的效果。这为实际应用提供了一定的数据支持。

The hardness of industrial desalination wastewater is high. The removal of magnesium ion and calcium ion inthe system were studied by chemical method and adsorptive method. First of all, the magnesium ion in the wastewater wasprecipitated by calcium oxide. Second, the calcium ion in the grltrate ,in which magnesium ion has been removed, wasadsorbed by zeolite. In addition, calcium ion was removed using carbon dioxide method, which is environmental friendly.The results show that the best operation conditions include： the mole ratio of calcium ion in calcium oxide solution andmagnesium ion in wastewater is 1.5; the pH value regulator is not necessary to be added into the system; when the amountof zeolite is 2 g and oscillation time is 16 h, the precipitation rate of calcium ion can reach 100% for the treatment of 200mL fitlrate. Therefore, carbon dioxide has a certain effect on the removal of calcium ions. The research has guiding role inthe practical application of removal of calcium ion and magnesium ion in desalination wastewater.