CrO42-对两种可变电荷土壤吸附钾的影响

用一次平衡法研究了CrO4^2-对两种可变电荷土壤吸附钾的影响，用火焰光度法测定平衡溶液中的钾，根据差减法计算土壤对钾的吸附量。结果表明，加入铬酸根能增加土壤对钾的吸附量。铬酸根对钾吸附的影响程度与土壤游离氧化铁含量和土壤对铬酸根的吸附量的大小有关。砖红壤游离氧化铁含量高于红壤，它对铬酸根的吸附量也大于红壤，因此，铬酸根对砖红壤吸附钾的影响程度大于红壤。CrO4^2-主要通过自身的吸附增加土壤的表面净负电荷，并从而增加土壤对钾的吸附量。

Effect of CrO42- on adsorption of K+ by two variable charge soils

The effect of CrO4 on adsorption of K+ by two variable charge soils was investigated using a batch method. The K+ 2- concentration in equilibrium solutions was determined by flame photometry and the amount of K+ adsorbed was calculated from the difference between the amount of K+ added and the amount remaining in an equilibrium solution. The results indicated that CrO4 2- increased the adsorption of K+ by the soils through the adsorption of CrO4 itself and the increase in net negative surface charge of 2- the soils. The effect was also related to the content of iron oxides in the soils and the amount of CrO4 adsorbed by the soils. When 2- the two soils were compared, it was found that the bigger adsorption of CrO4 by latosol due to its higher content of iron oxides 2- resulted in the more increase in K+ adsorption.