采用对土壤不同粒径的分选,进而了解Cr^6+在土壤中分布的特点。试验结果显示,对两种类型的土壤(水稻土和潮土),分选的5个粒级中,吸附Cr^6+的浓度随着粘土、粉粒、沙粒的顺序而增加。粒径0.075~0.005 mm的土壤对Cr^6+的吸附贡献率最大。活性氧化铁和活性氧化铝是影响Cr^6+吸附的主要因素。活性氧化铁和活性氧化铝含量越高,对Cr^6+吸附量越大。土壤中有机质含量与土壤吸附Cr^6+的量呈负相关。采用逐步回归法分析表明两种类型的土壤Cr^6+吸附量可以用多元线性回归模型表示,Cr^6+吸附量与土壤有机质、活性氧化铁、活性氧化铝存在相关性。
This paper used separating different soil particle size method to study two type soil: aquatic soil and paddy soil which were separated five size fractions. Results were summarized as follows: Cr (Ⅵ) concentration in different soil particles was in this order: Clay 〈 Silt 〈Loam. Using adsorption contribution index, metals were found to be associated largely with the fine particle-size fraction (0.075mm-0.005mm).Fe oxides and Al oxides are the two major factors affecting soil Cr (Ⅵ) adsorption. Based on the findings, using a stepwise regression method, a model was established to illuminate the relationship of Cr (Ⅵ) adsorption with organic matter content and CEC and Fe oxides and Al oxides.