三氯化铁吸附沉淀三价砷的影响因素研究

不采用预氧化步骤,直接使用三氯化铁吸附沉淀三价砷,系统考察了pH值、铁砷比、干扰离子浓度等因素对三氯化铁吸附沉淀三价砷的影响.在pH=4~10的范围内,吸附率随着pH值的升高先升后降,当pH=7时,吸附率达到最大.在铁砷比为30、pH为7时,三价砷的吸附率高达82.88%.含氧酸根阴离子如硫酸根、磷酸根、碳酸氢根对三价砷的吸附有竞争抑制作用,而碳酸氢根离子由于其特殊的pH缓冲效应,当溶液pH7时,其对吸附的影响表现为使溶液pH值上升进而小幅提高吸附率.钙、镁金属阳离子对三价砷的吸附有协同增强作用.

Study of influence factor on adsorption and precipitation of arsenite by ferric chloride

Without peroxidation treatment, arsenite in water was adsorbed and removed by ferric chloride in this paper.Influence factors of pH value,Fe/As ratio and interfering ions on the adsorption ratio were investigated in detail.Along the increasing of pH from 4 to 10,the adsorption ratio firstly increasing and then decreasing.The adsorption ratio reached the maximum value at pH=7.When Fe/As ratio was 30 and pH value was 7,the adsorption ratio was up to 82.88%.Oxygen acid radical anions, such as SO42-,PO43-, HCO3- had a competitive and suppressive effect on the adsorption of arsenite.When pH7,bicarbonate ion tended to buffer pH to a higher value then had a light enhanced effect on the adsorption of arsenite.Metal cations,such as Ca2+,Mg2+ had synergistic and enhanced effect on the adsorption of arsenite.