Influence of a nonionic surfactant on the water retention properties of unsaturated soils
Influence of a nonionic surfactant on the water retention properties of unsaturated soils
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DOI：
10.2136/sssaj2001.6551392x
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发表时间：
2001-09-01
影响因子：
2.9
通讯作者：
Young, MH
中科院分区：
文献类型：
--
作者：
Karagunduz, A;Pennell, KD;Young, MH
表面活性剂被广泛应用于家居产品、工业加工以及作为助剂来改善农用化学品的输送和有效性。由于表面活性剂的两亲性，它们往往聚集在气-液和固-液界面，因此有可能影响水在非饱和土壤中的流动和滞留。本研究的目的是研究非离子表面活性剂Triton X-100对F-70渥太华沙土的界面性质和毛细管压水关系的影响。在表面活性剂存在下，土壤水分随着表面活性剂浓度从0g L(1)增加到Triton X-100的临界胶束浓度(0.15g L(-1))而递增。在相同的表面活性剂浓度范围内，水的表面张力从7.2×10~(-2)J~(-2)J~(-2)降至3.2×10~(-2)J~(-2)J~(-2)，固-液接触角从40度降至10度。当表面活性剂浓度高于CMC时，没有观察到界面性质或土壤水分特性的进一步变化。实验结果被用来开发和评价基于van Genuchten模型的描述土壤水分特征随浓度变化的替代尺度方法。一个结合了表面张力和含量角关系的比例因子提供了对一系列表面活性剂浓度范围内的土壤水分保持曲线的准确预测。在不需要表面张力和接触角数据的情况下，基于单一的拟合参数，还发展了比例因子的简化形式。虽然还需要进一步验证简化的比例因子，但这种方法提供了一种有效的方法来描述界面性质随浓度变化对土壤水分特性的影响。
Surfactants are widely used in household products, industrial processes and as adjuvants to improve the delivery and effectiveness of agrochemicals. Due to their amphiphilic nature, surfactants tend to accumulate at gas-liquid and solid-liquid interfaces, and thus, have the potential to influence water flow and retention in unsaturated soils. The objective of this study was to investigate the effects of a nonionic surfactant, Triton X-100, on the interfacial properties and capillary pressure-water content relationships of F-70 Ottawa sand and Appling soil. In the presence of surfactant, soil water contents decreased incrementally as the surfactant concentration was increased from 0 g L (1) up to the critical micelle concentration (CMC) of Triton X-100 (0.15 g L(-1)). Over the same surfactant concentration range, the surface tension of water decreased from 7.2 X 10(-2) J m(-2) to 3.2 x 10(-2) J m(-2) while solid-liquid contact angle decreased from 40 degrees to 10 degrees. No further changes in interfacial properties or soil water characteristics were observed at surfactant concentrations above the CMC. The experimental results were used to develop and evaluate alternative scaling approaches to describe concentration dependent changes in soil water characteristics based on the van Genuchten model. A scaling factor that incorporated both surface tension and content angle relationships provided accurate predictions of soil water retention curves over a range of surfactant concentrations. A simplified form of the scaling factor also was developed, on the basis of a single fitting parameter without the need for surface tension and contact angle data. Although further validation of the simplified scaling factor will be required, this approach offers an efficient means to describe the effects of concentration dependent changes in interfacial properties on soil water characteristics.