铁砷复合污染下铁砷比对除砷效果的影响研究

针对铁砷复合污染型地下水,以原水铁砷比作为控制参数,通过烧杯试验研究了曝气接触氧化除铁工艺的除砷效果。结果表明,当初始砷含量分别为100,200,300和400μg/L时,原水铁砷比分别为35∶1,50∶1,52∶1和55∶1,能达到除铁效果且同时满足出水砷含量小于10μg/L的限值要求;根据氢氧化铁对砷的吸附机理,利用Freundlich吸附等温式建立了铁砷比与残余砷含量的数学模型,试验数据拟合结果与模型相吻合。此外,采用曝气氧化工艺处理铁砷复合污染地下水时,可以通过投加二价铁盐控制原水铁砷比,以实现同时去除铁砷的目的。

Influence of Fe/As ratio on arsenic removal efficiency under conbined contamination of iron and arsenic

Aimed at the groundwater which was contaminated by iron and arsenic, and selected the Fe/As ratio as control parameter in raw water, the arsenic removal effect of aeration contact oxidation iron removal process was investigated by beaker test. The results showed that the Fe/As ratio could be 35 ： 1, 50 ： 1, 52 ： 1 and 55 ： 1 respectively when the initial concentrations of arsenic were 100, 200, 300 and 400 ixg./L respectively. It could remove iron and satisfy the requirement of outflow arsenic concentration of less than 10 ~Lg/L. According to the adsorption mechanism of ferric hydroxide on arsenic, the mathematical model of Fe/As ratio and residual arsenic concentration was built by Freundlich adsorption isotherm. The simulation results of test data were close to the model. In addition, the results indicated that it could remove iron and arsenic simultaneously by dosing ferrous salts in order to control Fe/As ratio in raw water when the aeration oxidation process was used to treat groundwater with combined contamination of iron and arsenic.