Prediction of soil bases and aluminum ion leaching by the acid rain infiltration.

酸雨渗透土壤碱基和铝离子淋溶预测。

• 批准号: 11660237
• 负责人: MATSUKAWA Susumu
• 金额: $ 1.41万
• 依托单位: Utsunomiya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11660237/
• 关键词: acid rain; sulfuric acid solution; pH prediction; chemical equation; mixing cell model; anion adsorption; aluminum ion; volcanic ash soil; 土壌; 酸緩衝機能; ミキシング・セル

The chemical equilibrium equations which describe the acid buffering capacity of soil were combined with mixing cell model, describes the water movement in soil approximately, to predict the soil bases and aluminum ion leaching owing to pH2 and pH3 sulfuric solution infiltration. The equilibrium equations were composed of aluminum dissolution, ion exchange between dissolved aluminum and bases, bicarbonate formation, sulfuric ion adsorption, charge balance and mass balance of sulfuric ion and bases, respectively. Ion exchange between dissolved aluminum ion and soil bases were lumped together with mineral weathering as acid buffering terms. Mixing cell size depends on dispersivity and that value was decided by the effluent curves of relative sulfuric ion concentration measurements.Reactions between soil and sulfuric solution depend on both contact surface area and surface area of the soil is different by the size of the soil particle. Clarify the buffering effects on soil particle size, soil column was packed with less than 2mm or 0.4mm aggregate volcanic ash soil, respectively. Infiltration measurements with pH2 and pH3 sulfuric acid solution, amount of leaching bases and that of adsorbed sulfuric ion was large in 0.4mm aggregate soil column compared with 2mm ones. These results implied that acid buffering capacities were depend on the soil-solution contact surface area and these effects must be considered in the simulations.The simulation results considering the contact surface area between acid solution and soil, measured and simulated effluent pH were well correspondent in the case of pH2 sulfuric acid solution leaching. However, simulation results of pH3 leaching were not correspondent well. This discrepancy may reflect an underestimation of sulfuric ion adsorption in low concentration sulfuric solution range. It is necessary to construct the anion adsorption curves as the function pH and concentration in detail.

将描述土壤酸缓冲能力的化学平衡方程与混合池模型相结合，近似地描述了土壤中的水分运动，预测了pH2和pH3硫酸溶液入渗对土壤碱和铝离子的淋滤作用。平衡方程由铝的溶解、铝与碱的离子交换、碳酸氢盐的形成、硫离子的吸附、硫离子与碱的电荷平衡和质量平衡组成。将溶解铝离子与土壤碱基之间的离子交换与矿物风化统称为酸缓冲项。混合池的大小取决于分散性，分散性由相对硫离子浓度测量的流出曲线决定。土壤与硫酸溶液之间的反应取决于土壤的接触表面积，土壤的表面积因土壤颗粒的大小而不同。明确了缓冲作用对土壤粒径的影响，土柱分别填充小于2mm和0.4mm的骨料火山灰土。ph为2和ph为3的硫酸溶液在0.4mm团聚体土柱中的入渗量、浸出碱量和吸附硫离子量均大于2mm团聚体土柱。这些结果表明，酸缓冲能力取决于土壤-溶液接触表面积，在模拟中必须考虑这些影响。考虑酸液与土壤的接触面积，在pH2硫酸溶液浸出情况下，实测出水pH与模拟出水pH吻合较好。但pH3浸出的模拟结果并不吻合。这种差异可能反映了对硫离子在低浓度硫酸溶液范围内吸附的低估。有必要详细地建立酸碱度和浓度对阴离子的吸附曲线。