Influence of Coexistent Ions Fe3+ and Mn2+ on Arsenic (III) Adsorption Behaviour onto River Sediment

摘要

To understand the influencing factors of the sediment adsorption of As 3+ , prototype sand of the Yellow Riverwas taken as the material. The effects of sediment adsorption saturation time and adsorption regularitieswere investigated when coexisting ions Fe 3+ and Mn 2+ existed. The results show that: (1) when there wasonly As 3+ existing alone, the saturation time was 60 min; when Fe 3+ and Mn 2+ were added, the saturation timewas 90 min; (2) when Fe 3+ existed, the sediment adsorption laws of As 3+ were as follows: during the initialperiod, with the increasing concentration of Fe 3+ , the adsorption decreased; when the concentration of Fe 3+was more than 0.4mg/L, the adsorption capacity increased with the increasing concentration of Fe 3+ ; whenthere was Mn 2+ existing, the regulation also showed that it initially decreased slightly and then increased, i.e.,when Mn 2+ was less than 1.0mg/L, the adsorption capacity decreased with the increasing concentration ofMn 2+ ; when Mn 2+ was higher than 1.0mg/L, the adsorption capacity increased with the increasing concentrationof Mn 2+ ; when Fe 3+ and Mn 2+ coexisted, the sediment adsorption of As 3+ increased with the increasingconcentration of the coexisting ions; (3) when the coexisting ion concentration was 0.2-0.4mg/L, the removalrate of Fe 3+ was less than that of Mn 2+ , and also less than that of the coexistence of Fe 3+ and Mn 2+ . When theconcentration of coexistent ions is less than 0.2 or more than 0.4 mg/L, the removal rate of Mn 2+ was lessthan Fe 3+ , and also less than that of the coexistence of Fe 3+ and Mn 2+ .