Institute of Chemistry and Technology of Environmental Protection, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic.
Central European Institute of Technology, Purkyňova 123, 61200 Brno, Czech Republic.
Sci Total Environ. 2019 Dec 1;694:133822. doi: 10.1016/j.scitotenv.2019.133822. Epub 2019 Aug 6.
Engineered and anthropogenic nanoparticles represent a new type of pollutants. Up until now, many studies have reported its adverse effect on biota, but the potential influence on the properties and functions of environmental compartments has largely been ignored. In this work, the effect of Pt nanoparticles on the functions and properties of model soil organic matter has been studied. Using differential scanning calorimetry and molecular modeling, the effect of a wide range of 3 nm Pt nanoparticles concentrations on water holding capacity, the strength of water binding, the stability of water molecule bridges and the content of aliphatic crystallites was studied. It was found that strong hydration of the nanoparticles influences the 3D water structural network and acts as kosmotropic agents (structure-forming) in water bridges and as chaotropic agents (i.e. water destructuring) in larger water volumes. Contrarily, the interaction with soil organic matter moieties partially eliminates these effects. As a result, the 3 nm Pt nanoparticles decreased the evaporation enthalpy of water in soil organic matter and supported soil desiccation. They also increased the strength of water molecule bridges and increased the soil structural rigidity even at low concentrations. Additionally, at high concentrations, they decreased the water content in soil organic matter and induced the aliphatic moieties' crystallization. It is concluded that the small-sized Pt nanoparticles, and perhaps other types as well, may affect the local physicochemical processes in soils and may consequently contribute to enhanced evapotranspiration and deterioration of soil functions.
工程纳米粒子和人为纳米粒子代表了一种新型污染物。到目前为止，许多研究都报告了它们对生物群的不良影响，但对环境介质特性和功能的潜在影响在很大程度上被忽视了。在这项工作中，研究了 Pt 纳米粒子对模型土壤有机质功能和特性的影响。使用差示扫描量热法和分子建模，研究了广泛浓度范围内的 3nm Pt 纳米粒子对持水能力、水结合强度、水分子桥稳定性和脂肪结晶含量的影响。结果发现，纳米粒子的强烈水合作用影响了 3D 水结构网络，并在水桥中充当向溶媒（结构形成），在较大的水体中充当离溶媒（即水破坏）。相反，与土壤有机质部分的相互作用部分消除了这些影响。因此，3nm Pt 纳米粒子降低了土壤有机质中水分的蒸发焓，并支持土壤干燥。它们还增加了水分子桥的强度，即使在低浓度下也增加了土壤结构的刚性。此外，在高浓度下，它们降低了土壤有机质中的含水量，并诱导脂肪族部分结晶。研究结论表明，小尺寸的 Pt 纳米粒子（也许还有其他类型的纳米粒子）可能会影响土壤中的局部物理化学过程，并可能导致增强的蒸散作用和土壤功能的恶化。
