Search results for " water molecule bridges"

showing 2 items of 2 documents

Hydration and water holding properties of cross-linked lignite humic acids

2014

Abstract Lignite and lignite humic acids, which are used as soil amendments sometimes, are supposed to improve soil properties such as water holding capacity. The structure of those materials is composed of various organic molecules stabilized mostly by weak interactions. Therefore, excess of water causes only partial swelling, but most of the physical structure is destabilized. This accelerates the desiccation and hampers their application as natural hydrogel-like substances. In order to stabilize the structure of lignite humic acids and improve the water holding capacity, we applied formaldehyde cross-linking procedure based on covalent coupling of aromatic humic acids moieties. By combin…

MoistureEnvironmental remediationChemistrySettore AGR/13 - Chimica AgrariaSoil ScienceSorptioncomplex mixturesSoil conditionerlignite humic acids cross-linking hydration DSC NMR relaxometry water molecule bridgesChemical engineeringSoil watermedicineOrganic chemistryRelative humiditySwellingmedicine.symptomThermal analysis
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Combined proton NMR wideline and NMR relaxometry to study SOM-water interactions of cation-treated soils

2013

Abstract Focusing on the idea that multivalent cations affect SOM matrix and surface, we treated peat and soil samples by solutions of NaCl, CaCl2 or AlCl3. Water binding was characterized with low field 1H-NMR-relaxometry (20 MHz) and 1H wideline NMR spectroscopy (400 MHz) and compared to contact angles. From 1H wideline, we distinguished mobile water and water involved in water molecule bridges (WaMB). Large part of cation bridges (CaB) between SOM functional groups are associated with WaMB. Unexpectedly, 1H NMRrelaxometry relaxation rates suggest that cross-linking in the Al-containing peat is not stronger than that by Ca. The relation between percentage of mobile water and WaMB water in…

Dewey Decimal Classification::500 | Naturwissenschaften::550 | GeowissenschaftenDewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften BiologieDewey Decimal Classification::600 | Technik::630 | Landwirtschaft VeterinärmedizinAnalytical chemistrySoil organic matter (SOM); Low field 1H NMR relaxometry; 1H wideline NMR spectroscopy; Contact angle; Cation bridges; Water molecule bridges.TA Engineering (General). Civil engineering (General)soil organic matter (som)Low field H-1 NMR relaxometrystateContact angleNuclear magnetic resonancewater molecule bridgesddc:550ddc:630natural organic-mattercontact angleWater Science and TechnologyFluid Flow and Transfer Processeschemistry.chemical_classificationhumic substancesWater molecule bridges.Nuclear magnetic resonance spectroscopycation bridgesCation bridgemultiexponential decay datanuclear-magnetic-resonanceH-1 wideline NMR spectroscopyProton NMRWater bindingTC1-978Relaxometryuniform-penalty inversionlow field 1h nmr relaxometrySettore AGR/13 - Chimica AgrariaContext (language use)1h wideline nmr spectroscopyforest soilsCation bridgesddc:570sandy soilOrganic mattercontact-angleContact angleSoil organic matter (SOM)repellencyMechanical EngineeringHydraulic engineeringchemistrySoil waterWater molecule bridgesJournal of Hydrology and Hydromechanics
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