Speciation and adsorption of arsenic on diagenetic iron oxyhydroxides
Speciation and adsorption of arsenic on diagenetic iron oxyhydroxides
复制标题
DOI：
10.4319/lo.1991.36.7.1480
复制
发表时间：
1991-11
影响因子：
4.5
通讯作者：
R. D. Vitre;N. Belzile;A. Tessier
中科院分区：
文献类型：
--
作者：
R. D. Vitre;N. Belzile;A. Tessier
通过在垂直插入表层沉积物中的聚四氟乙烯捕收器上沉积，从加拿大地盾的12个湖泊中获得了成岩Fe和As样品。沉淀物的溶解表明只有砷酸盐存在，即无法检测到亚砷酸盐浓度。实验室批量实验表明，氢氧化铁能快速氧化As(III)。从成岩物质沉积物中溶解的Fe和As浓度以及湖泊沉积物上覆水中As浓度计算了As吸附的表观平衡常数。这些场导出的平衡常数与实验室导出的砷在无定形氢氧化铁上的吸附平衡常数吻合得很好，综合起来，实验室常数可以用来模拟天然水中无机砷在氢氧化铁上的吸附。
Diagenetic Fe and As samples have been obtained from 12 lakes on the Canadian Shield by deposition on Teflon collectors inserted vertically in the surficial sediments. Dissolution of the deposits showed that only arsenate was present, i.e. arsenite concentrations were undetectable. Laboratory batch experiments indicated that As(III) is oxidized rapidly by Fe oxyhydroxides. Apparent equilibrium constants for the absorption of As have been calculated from the Fe and As concentrations dissolved from the deposit of diagenetic material and As concentration in the water overlying the lake sediments. These field-derived equilibrium constants agree well with laboratory-derived equilibrium constants for the absorption of arsenate on amorphous Fe oxyhydroxides; the results taken together suggest that the latter laboratory constants can be used for modeling adsorption of inorganic As on Fe oxyhydroxides in natural waters.