scholarly journals Quantity of Hydrophobic Functional CH-Groups – Decisive for Soil Water Repellency Caused by Digestate Amendment

2015 ◽  
Vol 29 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Amrei Voelkner ◽  
Dörthe Holthusen ◽  
Ruth H. Ellerbrock ◽  
Rainer Horn
Keyword(s):  
Organic Matter ◽  
Fourier Transform ◽  
Functional Groups ◽  
Mineral Soil ◽  
Dilution Effect ◽  
Water Repellency ◽  
Organic Fertilizers ◽  
Fourier Transform Spectra ◽  
Diffuse Reflectance Infrared ◽  
Anaerobic Digestates

Abstract Anaerobic digestates are used as organic fertilizers; however, they are suspected to interfere negatively with soils. To investigate the relevance of the anaerobic digestates composition on potential wettability and contact angle of the soil, we mixed in a laboratory experiment 30 m³ ha-1 of anaerobic digestates derived from mechanically pre-treated substrates from maize and sugar beet with a homogenized Cambic Luvisol. Fourier transform infrared-spectra and diffuse reflectance infrared Fourier transform-spectra of particle intact and finely ground soilanaerobic digestates-mixtures were analyzed to determine the quantities of hydrophobic functional groups in the soil-anaerobic digestates-mixtures that are used here as an indicator for the potential hydrophobicity. The anaerobic digestates application increased the amount of hydrophobic functional groups of the mixtures and reduced the wettability of the soil. However, for intact particle samples an up to threefold higher amount of hydrophobic groups was found as compared to the finely ground ones, indicating a dilution effect of mechanical grinding on the effectivity of the organic matter that is presumably located as a coating on mineral soil particles. For the particle intact samples, the intensity of hydrophobic functional groups bands denoting hydrophobic brickstones in organic matter is indicative for the actual wettability of the soil-anaerobic digestates-mixtures.

The relationship of soil water repellency to aliphatic C and kaolin measured using DRIFT

Soil Research ◽  
2003 ◽  
Vol 41 (2) ◽  
pp. 251 ◽  
Author(s):  
I. McKissock ◽  
R. J. Gilkes ◽  
W. van Bronswijk
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Soil Texture ◽  
Water Repellency ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Organic C ◽  
Aliphatic Carbon ◽  
Fourier Transform Spectra ◽  
Diffuse Reflectance Infrared

In general, water repellency by soil increases with the increase of total organic matter and decreases as the clay and silt contents of the soil increase. The prediction of water repellency from soil organic carbon (OC) content may be improved by examining the types of carbon associated with water repellency. This paper examines the hypothesis that measurement of aliphatic C can provide a better prediction of water repellency than measurement of total OC and also looks at the effects of soil texture on water repellency and the amount of aliphatic C in the soil. DRIFT (diffuse reflectance infrared fourier transform) spectra were measured on sandy soils from the West Midland Sandplains north of Perth in Western Australia. The areas of the aliphatic CH stretching signal (3000–2800/cm) and the OH stretching signal due to kaolin (3750–3570/cm) were used as relative measures of aliphatic carbon and kaolin contents. The relationships of aliphatic C and kaolin to water repellency have been examined and compared with the relationships of water repellency to total OC and clay contents of soil.Hydrophobic organic C as measured by DRIFT gave a better prediction of soil water repellency (r2 = 0.45) than did the total OC (r2 = 0.36). The specific hydrophobicity of organic matter (aliphatic C/OC ratio) increased as sand content increased. However, the direct influence of soil texture on water repellency was of more significance than its indirect influence on the amounts and forms of soil organic matter. A multivariate model including aliphatic C and clay + silt content was the best model for describing water repellency (r2 = 0.58). DRIFT is an effective, rapid method for screening soils for water repellent properties.For individual sand grains there was a weak positive relationship (r2 = 0.26) between the size of the aliphatic CH peak measured from surfaces of sand grains and the water repellency of the grains. A discontinuous aliphatic surface layer was present on the surface of individual sand grains.

scholarly journals Characterization of wastewater from landfills - amount and type of humic substances extracted from leachate

2019 ◽  
Vol 80 ◽  
pp. 03002
Author(s):  
Maria Elisabete Silva ◽  
Marlene Santos ◽  
Isabel Brás
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Functional Groups ◽  
Humic Acids ◽  
Fulvic Acids ◽  
Organic Fertilizers ◽  
Structural Composition ◽  
Carboxylic Groups ◽  
Humification Degree

This study aimed to characterize the humic substances (HS) extracted from landfills wastewater – leachates, with different ages of exploration. To reach the objective it was applied spectroscopy techniques, UV-Vis and FTIR spectra, as well as the ratio between the absorbance analysed. First, the HS were extracted, then fractionated in fulvic acids (FA) and humic acids (HA) and it was evaluated the phytotoxicity. HS content in the leachates were higher than the typical values found in the natural aquatic humic sources. It has been identified that the leachate HS, HA and FA aromatic fractions increased with the increase of the landfilling age, suggesting that the degree of humification increased with the landfilling age. All the HS showed a high aromaticity and humification degree. The HS extracts irrespective of their source presents similar structural composition. The functional groups found are in agreement with the literature: phenols, alcohols, carboxylic groups, aliphatic structures, among others. It was found that HA are mainly organic matter with a higher aromatic degree than FA. The HS and HA showed absence of phytotoxicity, testing by germination index, suggesting that may be used to produce liquid organic fertilizers.

scholarly journals Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) applied to the chemical characterization of Diesel soot

2016 ◽  
Vol 18 (3) ◽  
pp. 453-462 ◽  
Keyword(s):  
Fourier Transform ◽  
Sample Preparation ◽  
Functional Groups ◽  
Diffuse Reflectance ◽  
Chemical Characterization ◽  
Operating Mode ◽  
Diesel Soot ◽  
Fourier Transform Spectroscopy ◽  
Different Temperatures ◽  
Diffuse Reflectance Infrared

<div> <p>In this work, diesel soot has been characterized chemically using a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique. Diesel soot samples were generated under combustion conditions reproducing the typical urban operating mode of a diesel engine. Initial experiments performed to ensure the repeatability of the Drifts analysis and the sample preparation method showed that the standard deviations were always lower than 20% for the DRIFTS analysis itself, and lower than 25% when sample preparation was included. This is of special interest as regards application of the DRIFTS technique for quantitative analysis. The functional groups on the soot surface were identified on the basis of the infrared bands observed in the spectra at room temperature, indicating that the diesel soot analyzed comprises a mixture of aromatic hydrocarbons, carboxylic compounds, hydroxyl species, ether groups, and methylene and methyl groups. Analyses were also carried out at different temperatures in the interval of 298-858 K in order to analyze the thermal stability of the functional groups, with carbonyl groups, lactones and ethers appearing to be the most thermally stable compounds.&nbsp;</p> </div> <p>&nbsp;</p>

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