1H NMR Relaxometry in Natural Humous Soil Samples: Insights in Microbial Effects on Relaxation Time Distributions

Jaeger, Fabian; Grohmann, Elisabeth; Schaumann, Gabriele E.

doi:10.1007/s11104-005-3035-4

Cited by 49 publications

(44 citation statements)

References 37 publications

(55 reference statements)

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“…These findings were attributed to a redistribution of water during swelling. Todoruk et al [6] identified two processes with time constants of about 1 d for a fast process and up to 22 d for a slow process for different soils, which were comparable to the values reported by Schaumann et al [2,12] and Jaeger et al [13]. The calculated activation energies of these two processes ranged from 14 kJ mol -1 to 117 kJ mol -1 suggesting diffusion processes and chemical reactions, such as ester hydrolysis [6].…”

Section: Introductionsupporting

confidence: 73%

“…Additionally to the calculation of Q, 1 H NMR relaxometry [2,6,7,12,13] and DSC [7,14] were used to study the hydration of peat and mineral soil samples or to characterise different types of water in peats. DSC was used to study the melting and freezing behaviour of water and to calculate the amounts of non-freezable and freezable water in hydrogels [15,16] or peat soil samples [7,14].…”

Section: Introductionmentioning

confidence: 99%

“…Swelling kinetics experiments of soil samples using 1 H NMR relaxometry have shown that the swelling process is linked to the migration of the peak relaxation times towards smaller relaxation times and the increase of the amount of water protons relaxing at smaller relaxation times [2,6,12,13]. These findings were attributed to a redistribution of water during swelling.…”

Section: Introductionmentioning

confidence: 99%

“…The changes in the relaxation time distributions during swelling of soils were found to be pronounced stronger in soils with higher microbial respiratory activity [13] and in soils inoculated with a biofilm producing bacteria isolate [18]. Consequently, soil microorganisms may contribute to the swelling of soils due to the production and release of extracellular polymeric substances (EPS) and the formation of biofilm.…”

Section: Introductionmentioning

confidence: 99%

“…In general, transverse relaxation times (T 2 ) are used to study the swelling of soil samples [6,12,13], because of the much faster determination compared to longitudinal relaxation times (T 1 ). However, many swellable materials, such as cellulose [21], hydrogels with different degrees of crosslinking [22], wheat starch [23] and maltodextrin [17] show strong differences between T 1 and T 2 .…”

Section: Introductionmentioning

confidence: 99%

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Proton NMR Relaxometry as a Useful Tool to Evaluate Swelling Processes in Peat Soils~!2009-07-26~!2009-12-04~!2010-06-15~!

Jaeger¹,

Shchegolikhina²,

As³

et al. 2010

TOMRJ

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Dramatic physical and physico-chemical changes in soil properties may arise due to temperature and moisture variations as well as swelling of soil organic matter (SOM) under constant conditions. Soil property variations may influence sorption/desorption and transport processes of environmental contaminants and nutrients in natural-organic-matterrich soils. Notwithstanding the studies reported in literature, a mechanistic model for SOM swelling is unavailable yet. The objective of the present study was the evaluation of the swelling of peat soils, considered as SOM models, by 1 H NMR relaxometry and differential scanning calorimetry (DSC). Namely, information on the processes governing physical and physicochemical changes of peat during re-hydration were collected. The basic hypothesis of the present study was that the changes are slow and may affect water state as well as amounts of different water types into the peats. For this reason, such changes can be evidenced through the variations of mobility and thermal behaviour of the involved H 2 O molecules by using 1 H NMR relaxometry and DSC. According to the experimental results, a mechanistic model, describing the fundamental processes of peat swelling, was obtained. Two different peats re-wetted at three temperatures were used. The swelling process was monitored by measuring spin-spin relaxation time (T2) over a hydration time of several months. Moreover, DSC, T1 -T2 and T2 -D correlation measurements were done at the beginning and at the end of the hydration. Supplementary investigations were also done in order to discriminate between the swelling effects and the contributions from soil solution, internal magnetic field gradients and/or soil microorganisms to proton relaxation. All the results revealed peat swelling. It was evidenced by pore size distribution changes, volumetric expansion and redistribution of water, increasing amounts of nonfreezable and loosely bound water, as well as formation of gel phases and reduction of the translational and rotational mobility of H 2 O molecules. All the findings implied that changes of the physical and physicochemical properties of peats were obtained. In particular, three different processes having activation energies comprised in the interval 5 -50 kJ mol -1 were revealed. The mechanistic model which was, then, developed included water reorientation in bound water phases, water diffusion into the peat matrix and reorientation of SOM chains as fundamental processes governing SOM swelling. This study is of environmental significance in terms of re-naturation and re-watering of commercially applied peatlands and of sorption/desorption and transport processes of pollutants and nutrients in natural organic matter rich soils.

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Section: Introductionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Proton NMR Relaxometry as a Useful Tool to Evaluate Swelling Processes in Peat Soils~!2009-07-26~!2009-12-04~!2010-06-15~!

Jaeger¹,

Shchegolikhina²,

As³

et al. 2010

TOMRJ

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Nuclear magnetic resonance characterization of shallow marine sediments from the Nankai Trough, Integrated Ocean Drilling Program Expedition 333

et al. 2014

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We measured nuclear magnetic resonance (NMR) relaxation times on samples from Integrated Ocean Drilling Program Expedition 333 Sites C0011, C0012, and C0018. We compared our results to permeability, grain size, and specific surface measurements, pore size distributions from mercury injection capillary pressure, and mineralogy from X-ray fluorescence. We found that permeability could be predicted from NMR measurements by including grain size and specific surface to quantify pore networks and that grain size is the most important factor in relating NMR response to permeability. Samples within zones of anomalously high porosity from Sites C0011 and C0012 were found to have different NMR-permeability relationships than samples from outside these zones, suggesting that the porosity anomaly is related to a fundamental difference in pore structure. We additionally estimated the size of paramagnetic sites that cause proton relaxation and found that in most of our samples, paramagnetic material is present mainly as discrete, clay-sized grains. This distribution of paramagnetic material may cause pronounced heterogeneity in NMR properties at the pore scale that is not accounted for in most NMR interpretation techniques. Our results provide important insight into the microstructure of marine sediments in the Nankai Trough.

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Soil-Water Interactions

Schaumann

Bertmer

1996

eMagRes

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1H NMR Relaxometry in Natural Humous Soil Samples: Insights in Microbial Effects on Relaxation Time Distributions

Cited by 49 publications

References 37 publications

Proton NMR Relaxometry as a Useful Tool to Evaluate Swelling Processes in Peat Soils~!2009-07-26~!2009-12-04~!2010-06-15~!

Proton NMR Relaxometry as a Useful Tool to Evaluate Swelling Processes in Peat Soils~!2009-07-26~!2009-12-04~!2010-06-15~!

Nuclear magnetic resonance characterization of shallow marine sediments from the Nankai Trough, Integrated Ocean Drilling Program Expedition 333

Soil-Water Interactions

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