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首页> 外文期刊>Environmental toxicology and chemistry >Differential roles of humic acid and particulate organic matter in the equilibrium sorption of atrazine by soils.
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Differential roles of humic acid and particulate organic matter in the equilibrium sorption of atrazine by soils.

机译：腐殖酸和有机质颗粒在土壤对r去津的平衡吸附中的差异作用。

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摘要

Recent studies have indicated that soil organic matter (SOM) may consist of physically and chemically different fractions, including particulate organic matter (POM), such as black carbon and unburned coal materials. The present study examined the differential roles of three different SOM fractions isolated from a peat and a topsoil in the equilibrium sorption of the herbicide atrazine (ATZ). The SOM fractions isolated from the two samples included humic acids (HAs), base-extracted humin (HM), and POM after demineralization of HM. A batch technique was employed to measure both the nonequilibrium ATZ sorption on the original and HA samples and the equilibrium ATZ sorption and desorption. The results showed that the phase-distribution relationships measured under nonequilibrium conditions were more linear and had lower sorption-capacity parameters compared with their respective isotherms measured under equilibrium conditions. The sorption isotherms were variously nonlinear, with POM exhibiting the greatest organic carbon-normalized sorption capacity. There existed apparent sorption-desorption hysteresis for each sorbent-sorbate system. It appeared that the extracted HAs could facilitate hydrolysis of ATZ when the reaction time extended to 4 d or longer. The equilibrium sorptive behavior of the HAs therefore was not examined. The present study indicated that both original samples showed lower organic carbon-normalized sorption distribution coefficients compared with their respective SOM fractions, suggesting that a fraction of sorption sites in soil aggregates were not accessed by ATZ.
机译：最近的研究表明，土壤有机物（SOM）可能由物理和化学上不同的部分组成，包括颗粒有机物（POM），例如黑碳和未燃烧的煤质。本研究研究了从泥炭和表土中分离出的三种不同SOM组分在除草剂at去津（ATZ）平衡吸附中的不同作用。从两个样品中分离出的SOM馏分包括腐殖酸（HAs），碱提取的腐殖质（HM）和HM脱矿质后的POM。采用批处理技术来测量原始样品和HA样品上非平衡ATZ的吸附以及平衡ATZ的吸附和解吸。结果表明，与在平衡条件下测得的等温线相比，在非平衡条件下测得的相分布关系更线性，吸附容量参数更低。吸附等温线是各种非线性的，其中POM表现出最大的有机碳标准化吸附容量。每个吸附剂-被吸附物系统都有明显的吸附-解吸滞后。看来，当反应时间延长至4 d或更长时，提取的HA可以促进ATZ的水解。因此，没有检查HA的平衡吸附行为。本研究表明，两个原始样品均显示出比其各自的SOM分数更低的有机碳归一化吸附分布系数，这表明ATZ无法访问土壤团聚体中的一部分吸附位点。

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