Solid state NMR studies of fire-induced changes in the structure of humic substances

Almendros, G.; González-Vila, Francisco Javier; Martı́n, Francisco; Fründ, R.; Lüdemann, H.‐D.

doi:10.1016/0048-9697(92)90073-2

Cited by 93 publications

(63 citation statements)

References 22 publications

(24 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition, the initial presence of aryl C in the sapwood used in this study and kerogen used by Dennis et al (1982) means that at least at the lower heating temperatures, the aryl C is a mixture of lignin/kerogen derived aryl C originally present in the samples and that produced by heating. Similar progressive increases in aryl C content with increasing heating were noted when samples of humic and fulvic acid (Almendros et al, 1990(Almendros et al, , 1992 and ryegrass leaves (Knicker et al, 1996) were heated for increasing durations at 350 C. Formation of furan-like materials in the O-aryl spectral region is evident for materials containing significant quantities of cellulose (Shafizadeh, 1984;Pastorova et al, 1994). The oxygenated carbons in benzofuran and dibenzofuran resonate at chemical shift values of 155 and 156 ppm, respectively.…”

Section: Nmr Errors and Observability Of C In The Samplesmentioning

confidence: 59%

Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Baldock

Smernik

2002

Organic Geochemistry

751

516

View full text Add to dashboard Cite

The residues remaining after incomplete combustion of vegetation (char) can contribute significantly to the carbon content of soils. Char C is considered biologically inert relative to other forms of organic C in soils; however, the degree of biological inertness is likely to be a function of the extent that the combustion residues were altered during thermal treatment. The relationship between changes in chemical composition and biological inertness of char C created in the laboratory by heating Pinus resinosa sapwood to temperatures between 70 and 350 C was quantified. Heating at each temperature was maintained until the mass of the residual char material stabilised (AE 2%). Chemical composition of the chars was assessed by elemental analysis, solid-state 13 C nuclear magnetic resonance (NMR) spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The susceptibility of the heated sapwood to biological oxidation was quantified in a 120-day laboratory incubation. Thermal treatment at temperatures 5200 C induced significant variations in chemical composition. Changes in elemental contents and molar elemental ratios were consistent with an initial dehydration and the formation of unsaturated structures. The NMR and DRIFT data indicated that the changes in the chemical composition with increasing heating temperature included a conversion of O-alkyl C to aryl and O-aryl furan-like structures, consistent with results from work examining the chemical changes associated with thermal treatment of cellulose, the major component of wood. The chemical changes significantly reduced the ability of a microbial inoculum derived from decomposing Pinus resinosa wood to mineralise carbon contained in the charred samples. The C mineralisation rate constants decreased by an order of magnitude for wood heated to 5200 C. #

show abstract

Section: Nmr Errors and Observability Of C In The Samplesmentioning

confidence: 59%

Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Baldock

Smernik

2002

Organic Geochemistry

751

516

View full text Add to dashboard Cite

show abstract

“…Por encima de 200°C empiezan los procesos de "charring" (De la Rosa et al, 2008b), se trata de procesos carbonización que eliminan el hidrógeno y el oxígeno. Según demostraron Almendros et al (1992), cuando se alcanzan temperaturas por encima de los 300°C se producen cambios estructurales de las sustancias húmicas del suelo, previamente descarboxiladas a bajas temperaturas, se producen ciclaciones de forma que los residuos están compuestos principalmente por estructuras carbonosas aromáticas (fundamentalmente "black carbon") altamente resistentes a la oxidación (Knicker et al, 2005) y no existentes en la muestra calentada a temperaturas más bajas. Por ello, el cambio más habitual es el incremento en el contenido de formas de "black carbon" (Rumpel et al, 2007;De la Rosa et al, 2008b;Rovira et al, 2012).…”

Section: Cambios En La Composición Molecular De La Materia Orgánicaunclassified

Revisión de las investigaciones a nivel molecular sobre el impacto del fuego en la materia orgánica del suelo: progresos en el siglo XXI

Rosa

Knicker²,

González‐Pérez³

et al. 2014

CIG

Self Cite

View full text Add to dashboard Cite

show abstract

“…Organic matter present in compost is usually chemically complex and dicult to fractionate. Extraction procedures may remove only a fraction of the organic matter, and, consequently, nondestructive methods such as 13 C-NMR (Almendros et al, 1992) and FTIR (Fourier transform IR) (Tseng et al, 1996) spectroscopy have been used for the analysis of humus. Aiken et al (1985) divided humic substances into the following groups: humin (not soluble in water at any pH), humic acids (not soluble in water under acidic conditions) and fulvic acids (soluble in water under all pH conditions).…”

Section: Compost Environmentmentioning

confidence: 99%

Biodegradation of lignin in a compost environment: a review

Tuomela

Vikman

Hatakka

et al. 2000

Bioresource Technology

1,022

455

View full text Add to dashboard Cite

Composting is nowadays a general treatment method for municipal solid waste. Compostable household waste contains, together with vegetable material, varying amounts of papers and boards. In the European Union composting is regarded as one recycling method for packages and this will probably favour compostable packages, like papers and boards, in the future. Paper is made up of lignocellulose and it may contain up to 20% of lignin. Ecient degradation of papers in composting plants means that biodegradation of lignin is also needed. However, very little is known about lignin degradation by mixed microbial compost populations, although lignin degradation by white-rot fungi has been extensively studied in recent years. Organic material is converted to carbon dioxide, humus, and heat by compost microorganisms. It is assumed that humus is formed mainly from lignin. Thus, lignin is not totally mineralized during composting. The elevated temperatures found during the thermophilic phase are essential for rapid degradation of lignocellulose. Complex organic compounds like lignin are mainly degraded by thermophilic microfungi and actinomycetes. The optimum temperature for thermophilic fungi is 40±50°C which is also the optimum temperature for lignin degradation in compost. Ó

show abstract

Solid state NMR studies of fire-induced changes in the structure of humic substances

Cited by 93 publications

References 22 publications

Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood

Revisión de las investigaciones a nivel molecular sobre el impacto del fuego en la materia orgánica del suelo: progresos en el siglo XXI

Biodegradation of lignin in a compost environment: a review

Contact Info

Product

Resources

About