Influence of organic chemicals on aliphatic crystallites analyzed in whole soils

Ondruch, Pavel; Jäger, Alexander; Kučerík, Jiří; Bertmer, Marko; Schaumann, Gabriele E.

doi:10.1016/j.geoderma.2016.12.016

Cited by 8 publications

(8 citation statements)

References 29 publications

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“…T * was evaluated as the temperature of the peak maximum in the first derivative because the WaMBs transition is partially overlapped by further processes. These processes are endothermal events representing the melting of aliphatic crystalline moieties, which have been described and discussed in another study . The DSC curves show a step at T *, indicating the temperature at which the structural mobility increases as a result of the disruption of WaMBs, with T * ranging between 30 and 55 °C.…”

Section: Methodsmentioning

confidence: 77%

“…These processes are endothermal events representing the melting of aliphatic crystalline moieties, which have been described and discussed in another study. 40 The DSC curves show a step at T*, indicating the temperature at which the structural mobility increases as a result of the disruption of WaMBs, 20 with T* ranging between 30 and 55 °C. The WaMBs transition is partially overlapped with the melting of aliphatic crystallites whose origin and dynamic properties were analyzed in detail in our previous study.…”

Section: Methodsmentioning

confidence: 99%

“…The WaMBs transition is partially overlapped with the melting of aliphatic crystallites whose origin and dynamic properties were analyzed in detail in our previous study. 40 Because of the overlap of WaMBs with the melting event, T* was evaluated as the temperature of the peak maximum of the first derivative (Figure 1).…”

Section: Methodsmentioning

confidence: 99%

“…The DSC curves show a step at T *, indicating the temperature at which the structural mobility increases as a result of the disruption of WaMBs, with T * ranging between 30 and 55 °C. The WaMBs transition is partially overlapped with the melting of aliphatic crystallites whose origin and dynamic properties were analyzed in detail in our previous study . Because of the overlap of WaMBs with the melting event, T * was evaluated as the temperature of the peak maximum of the first derivative (Figure ).…”

Section: Methodsmentioning

confidence: 99%

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Influence of Organic Chemicals on Water Molecule Bridges in Soil Organic Matter of a Sapric Histosol

et al. 2017

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Water molecules in soil organic matter (SOM) can form clusters bridging neighboring molecular segments (water molecule bridges, WaMBs). WaMBs are hypothesized to enhance the physical entrapment of organic chemicals and to control the rigidity of the SOM supramolecular structure. However, the understanding of WaMBs dynamics in SOM is still limited. We investigated the relation between WaMBs stability and the physicochemical properties of their environment by treating a sapric histosol with various solvents and organic chemicals. On the basis of predictions from molecular modeling, we hypothesized that the stability of WaMBs, measured by differential scanning calorimetry, increases with the decreasing ability of a chemical to interact with water molecules of the WaMBs. The interaction ability between WaMBs and the chemicals was characterized by linear solvation energy relationships. The WaMBs stability in solvent-treated samples was found to decrease with increasing ability of a solvent to undergo H-donor/acceptor interactions. Spiking with an organic chemical stabilized (naphthalene) or destabilized (phenol) the WaMBs. The WaMBs stability and matrix rigidity were generally reduced strongly and quickly when hydrophilic chemicals entered the soil. The physicochemical aging following this destabilization is slow but leads to successive WaMBs stabilization and matrix stiffening.

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Section: Methodsmentioning

confidence: 77%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Influence of Organic Chemicals on Water Molecule Bridges in Soil Organic Matter of a Sapric Histosol

et al. 2017

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“…Sapric histosol, an organic soil with a high organic matter content and negligible mineral content, was collected from Totes Moor, which is located ∼30 km northwest of Hannover, Germany, consisting of peat bog and fen areas. As this soil has already been subjected to a large number of studies, ,,,,− it appeared as a good model for understanding the relationship between WaMB and SOM. The soil was collected from a profile above a drainage channel from a stronger decomposed layer (>30 cm), underlying an upper fibric histosol (peat) layer (0–30 cm) with a lower degree of humification .…”

Section: Experimental Sectionmentioning

confidence: 99%

Formation of Water Molecule Bridges Governs Water Sorption Mechanisms in Soil Organic Matter

Kučerík

Ondruch

Mouvenchery³

et al. 2018

Langmuir

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Adsorption is the main mechanism of capturing water in soil organic matter (SOM) under arid conditions. This process is governed by hydrophilic sites, which are gradually bridged via water molecule bridges (WaMB). Until now, the link between WaMB and other types of water molecules occurring in SOM during sorption has not been systematically investigated. In this work, we compared the formation and stability of WaMB simultaneously with the total water content, strength of water binding, and kinetics of water sorption in a vacuum-dried model SOM (sapric histosol) exposed to different relative water pressures. The same parameters were then determined in SOM exposed to reduced relative pressures. The adsorption resulted in an adsorption isotherm with a Langmuir-like part below a relative pressure of 0.5 and a Brunauer-Emmett-Teller-like isotherm at higher relative pressures. The WaMB formation was observed at a relative pressure of 0.32, which represented the pressure at which Langmuir-like part reached a plateau. The binding energy showed a linear decrease with an increasing pressure; the slope increased at a relative pressure of 0.46. Reduction of relative pressures above 0.46 showed that the water content remained constant, but the binding energy was lowered. In contrast, below a relative pressure of 0.46, the water content decreased, but the binding energy was not changed. The results indicate that in SOM exposed to different relative pressures, water exists in three types: first, it is strongly bound to primary sorption sites (Langmuir-like), second, it occurs in the form of WaMB water, which bridges functional groups and where predominates water-water interactions, and third, it occurs in the form of phase water, which is located in larger pores similar to the pure water phase. The latter either surrounds the WaMB and destabilizes it or, for higher water content, links individual WaMB and successively reduces their stabilizing effect. Formation of phase water leads to swelling processes including plasticizing effects and potential volume changes of SOM. Accordingly, the results suggest that at lower water relative pressures WaMB stabilizes the SOM structure, whereas at higher water relative pressures, it influences the formation of phase water and thereby the total water content in SOM.

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Factors influencing structural heat-induced structural relaxation of dissolved organic matter

Řezáčová

Conte

Komendová

et al. 2019

Ecotoxicology and Environmental Safety

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Influence of organic chemicals on aliphatic crystallites analyzed in whole soils

Cited by 8 publications

References 29 publications

Influence of Organic Chemicals on Water Molecule Bridges in Soil Organic Matter of a Sapric Histosol

Influence of Organic Chemicals on Water Molecule Bridges in Soil Organic Matter of a Sapric Histosol

Formation of Water Molecule Bridges Governs Water Sorption Mechanisms in Soil Organic Matter

Factors influencing structural heat-induced structural relaxation of dissolved organic matter

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