摘要
以镉絮体为研究对象,模拟自然地球化学条件下的变化,如pH值,泥沙含量,水流速,温度的变化对镉絮体的影响.结果表明,pH值对释放镉的影响较大.镉释放程度随着pH值的降低而升高.在pH值为5时,镉溶出最大超标1.36倍;pH值在6~9范围内变化时,镉不超标.在洪水期泥沙增多有利于镉浓度的降低,这是因为泥沙也是一种混凝剂.模拟酸性洪水期极端条件(360r/min,pHo5,泥沙含量为0.03g/L),镉超标0.24倍.镉离子浓度随着搅拌速度的提高而降低.镉絮体在温度为10~20℃内基本没有变化,但当升高温度到30oC时,镉离子浓度随着时间延长呈现下降趋势,并未发现超标现象.
'Chemical precipitation in the mild alkaline solution' was usually adopted to treat environmental cadmium pollution emergencies in rivers. After the emergency response, whether cadmium flocs in the bottom of the river release cadmium drew the attention of people. The effects of pH, rotating speed, the sediment content, and the temperature on the cadmium release were estimated in this study. The experimental results showed that the effect of pH was appreciable. The cadmium concentration was increased at the lower pH, and it decreased with pH increase. The cadmium concentration was 1.36 times than that in the standard of 5 μg/L at pH 5, and it didn't exceeded the standard within pH 6~9. The increase of sediment decreased the concentration of cadmium because sediment were the kind of coagulant. The cadmium concentration was 0.24 times than that in the standard under the condition of 360r/min, pHo 5, and sediment content of 0.03 g/L. Cadmium ion concentration decreased with the increase of rotating speed. The cadmium flocs remained stable when the temperature ranged from 10 to 20, and the cadmium concentration decreased with the time at 30℃.
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2013年第S1期245-248,共4页
China Environmental Science
基金
广西环保专项:龙江后评估
贺江后评估
环境保护部公益项目(201309051)
关键词
聚铝
镉
应急事件
poly aluminium
cadmium
emergency events
