Influence of Coexistent Ions Fe~(3+) and Mn~(2+) 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 River was taken as the material. The effects of sediment adsorption saturation time and adsorption regularities were investigated when coexisting ions Fe~(3+) and Mn~(2+) existed. The results show that: (1) when there was only As~(3+) existing alone, the saturation time was 60 min; when Fe~(3+) and Mn~(2+) were added, the saturation time was 90 min; (2) when Fe~(3+) existed, the sediment adsorption laws of As~(3+) were as follows: during the initial period, 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+); when there 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 of Mn~(2+); when Mn~(2+) was higher than 1.0mg/L, the adsorption capacity increased with the increasing concentration of Mn~(2+); when Fe~(3+) and Mn~(2+) coexisted, the sediment adsorption of As~(3+) increased with the increasing concentration of the coexisting ions; (3) when the coexisting ion concentration was 0.2-0.4mg/L, the removal rate 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 the concentration of coexistent ions is less than 0.2 or more than 0.4 mg/L, the removal rate of Mn~(2+) was less than Fe~(3+), and also less than that of the coexistence of Fe~(3+) and Mn~(2+).