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Adsorption of sulfamethoxazole and sulfapyridine antibiotics in high organic content soils ☆
Environmental Pollution ( IF 8.9 ) Pub Date : 2017-09-01 , DOI: 10.1016/j.envpol.2017.08.011
Kuen-Lin Chen , Li-Chun Liu , Wan-Ru Chen

Many antibiotics, including sulfonamides, are being frequently detected in soil and groundwater. Livestock waste is an important source of antibiotic pollution, and sulfonamides may be present along with organic-rich substances. This study aims to investigate the sorption reaction of two sulfonamides, sulfamethoxazole (SMZ) and sulfapyridine (SPY) in two organic-rich sorbents: a commercial peat soil (38.41% carbon content) and a composted manure (24.33% carbon content). Batch reactions were conducted to evaluate the impacts of pH (4.5–9.5) and background ions (0.001 M–0.1 M CaCl2) on their sorption. Both linear partitioning and Freundlich sorption isotherms fit the reaction well. The n values of Freundlich isotherm were close to 1 in most conditions suggesting that the hydrophobic partition is the major adsorption mechanism. In terms of SMZ, Kd declined with increases in the pH. SPY has a pyridine group that is responsible for adsorption at high pH values, and thus, no significant trend between Kd and pH was observed. At high pH ranges, SPY sorption deviated significantly from linear partitioning. The results suggested the sorption mechanism of these two sulfonamide antibiotics tended to be hydrophobic partitioning under most of the experimental conditions, especially at pH values lower than their corresponding pKa2. The fluorescence excitation emission matrix and dissolved organic carbon leaching test suggested composted manure has higher fulvic acid organics and that peat soil has higher humus-like organics. Small organic molecules showed stronger affinity toward sulfonamide antibiotics and cause the composted manure to exhibit higher sorption capacity. Overall, this study suggests that the chemical structure and properties of sulfonamides antibiotics and the type of organic matter in soils will greatly influence the fate and transport of these contaminants into the environment.

中文翻译:

高有机物含量土壤中磺胺甲恶唑和磺胺吡啶的吸附情况

在土壤和地下水中经常检测到许多抗生素,包括磺酰胺。牲畜废物是抗生素污染的重要来源,磺酰胺可能与富含有机物的物质一起存在。这项研究旨在研究两种磺胺类药物磺胺甲恶唑(SMZ)和磺胺吡啶(SPY)在两种富含有机物的吸附剂中的吸附反应:一种商品的泥炭土(碳含量为38.41%)和一种堆肥的肥料(碳含量为24.33%)。进行分批反应以评估pH(4.5–9.5)和背景离子(0.001 M–0.1 M CaCl 2)的影响)对其吸附。线性分配和弗氏吸附等温线都很好地适合了反应。Freundlich等温线的n值在大多数情况下接近1,这表明疏水性分配是主要的吸附机理。就SMZ而言,K d随着pH的增加而下降。SPY具有一个吡啶基团,负责在高pH值下吸附,因此,未观察到K d和pH之间的明显趋势。在高pH范围内,SPY吸附明显偏离线性分配。结果表明,在大多数实验条件下,特别是在pH值低于其相应的pK a2的情况下,这两种磺酰胺类抗生素的吸附机制倾向于疏水分配荧光激发发射矩阵和溶解性有机碳浸出试验表明,堆肥中的黄腐酸有机物含量较高,而泥炭土中的腐殖质样有机物含量较高。有机小分子对磺酰胺类抗生素表现出更强的亲和力,并导致堆肥对粪便的吸附能力更高。总体而言,这项研究表明,磺酰胺类抗生素的化学结构和性质以及土壤中有机物的类型将极大地影响这些污染物的命运和向环境中的转移。
更新日期:2017-09-04
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