黄土性土壤对Cr(Ⅵ)的净化作用及迁移规律研究

Study on Purification of Loessial Soil to Cr(Ⅵ) and Its Migration Characters

通过土柱淋滤试验,从动态角度研究了黄土性土壤对Cr( )的净化作用及迁移规律。研究结果表明:黄土性土壤对Cr( )是逐步地均匀地吸附的,直到吸附饱和。土壤对Cr( )净化吸附分为3个阶段:全吸附段、部分吸附段和吸附饱和段。受粘粒含量影响,黄土性土壤中Cr( )运移的速度不同,其顺序为粘化层<犁底层+老耕层<耕层<钙积层。在浓度一定的条件下,土层越厚,淋出液中Cr( )的零值延时越长,饱和吸附时间也越长。当淋入液Cr( )浓度为10.0mg/L时,对于黄土地区土层5.0m深度可作为对Cr( )的净化深度。当一定厚度的土壤层达到Cr( )吸附饱和状态时,如果持续增加污水淋入量,则Cr( )在土层内达到吸附饱和的界限下移。

By the leaching experiment of soil column, the purification of loessial soil to Cr(Ⅵ) and its migration characters were studied from dynamic researches. The results showed that Cr(VI) was adsorbed gradually and evenly in loessial soil, and this process ended in adsorption saturation. The adsorption and purification of loessial soil to Cr(VI) was divided into three stages which were complete adsorption, partial adsorption and saturation adsorption. The migration velocities of Cr(VI) in soil was relevant to contents of clay, and they were in an order: argillic horizon<plow pan<cultivated horizon<calcic horizon. At the concentration of Cr(VI) was constant, the thicker soil layer was, the longer time which Cr(VI) was examined in leachate was, and the longer time of saturation adsorption was. At the condition that concentration of Cr(VI) in sewage was less than 10.0mg/L, 5.0 meters could be regarded as purification depth of loessial soil to Cr(VI). When a certain depth soil layer reached saturated absorption, the limit of saturated absorption would move to deeper place if leaching quantity of sewage was continually increasing.