三氯化铁吸附沉淀三价砷的影响因素研究

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

摘要: 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.

Abstract: 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.