Kinetics of chemical weathering in b horizon spodosol fraction
Kinetics of chemical weathering in b horizon spodosol fraction
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b层斜溶胶部分化学风化动力学
DOI：
10.1029/90wr02393
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发表时间：
1991
影响因子：
5.4
通讯作者：
J. Schnoor
中科院分区：
文献类型：
--
作者：
S. Asolekar;R. L. Valentine;J. Schnoor
对缅因州的B层土壤进行了研究，以确定土壤溶液中氢离子浓度对风化速率的依赖性。土壤浓度和溶液化学对化学风化速率的影响也进行了研究。在pH 2.7和3.5的条件下，利用实验室pH-稳态连续反应器对两种浓度的B层土壤进行了研究。在去离子水和丙酮中洗涤尺寸范围为63-125 μm的均质化的B层土壤，并且使用而不进行进一步处理。在恒定pH值为2.7的条件下，对10、30和100 g/L土壤进行滴定得到的结果表明，风化速率（以μeq H+/hr/g土壤表示）不依赖于pH恒定反应器中的土壤浓度。为了测试溶质浓度对风化速率的影响，在两种不同浓度的累积溶质下进行实验。风化率是相同的，在两个溶质浓度，表明显着的反反应不太可能发生。在pH 2.7下的风化速率估计为0.53-0.93 μeq H+/hr/g土壤，在pH 3.0下为0.52 μeq H+/hr/g土壤，在pH 3.5下为0.36 μeq H+/hr/g土壤，在pH 4.0下为0.04 μeq H+/hr/g土壤。假设风化速率与{H+}m成比例，则分数阶m被确定为约0.8。结果与表面反应控制的溶解机制一致。
Studies on a B horizon soil from Maine have been conducted to determine the weathering rate dependence on hydrogen ion concentration in soil solution. Effects of soil concentration and solution chemistry on chemical weathering rate were also investigated. Studies were conducted using a laboratory pH-stat semicontinuous reactor at pH 2.7 and 3.5 for two concentrations of B horizon soil. Homogenized B horizon soil in the size range 63–125 μm was washed in deionized water and acetone and used without further treatment. Results obtained from titrations of 10, 30, and 100 g/L of soil at a constant pH of 2.7 suggest that the weathering rate, expressed in μeq H+/hr/g soil, does not depend on the soil concentration in the pH-stat reactor. In order to test the effect of solute concentration on weathering rate, experiments were performed at two different concentrations of accumulated solutes. Weathering rates were the same at the two solute concentrations, indicating that significant back reactions were not likely occurring. The weathering rate at pH 2.7 was estimated in the range 0.53–0.93 μeq H+/hr/g soil, at pH 3.0 as 0.52 μeq H+/hr/g soil, at pH 3.5 as 0.36 μeq H+/hr/g soil, and at pH 4.0 as 0.04 μeq H+/hr/g soil. Assuming a weathering rate proportional to {H+}m, the fractional order m was determined to be approximately 0.8. Results were consistent with a surface-reaction-controlled dissolution mechanism.