Thermal characterization of natural and synthetic humic substances

Ioselis, P.; Rubinsztain, Y.; Ikan, R.; Aizenshtat, Zeev; Frenkel, M.

doi:10.1016/0146-6380(85)90057-9

Cited by 24 publications

(14 citation statements)

References 10 publications

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“…Campanella and Tomassetti (1990) monitored the thermal degradation of HS with FT-IR spectroscopy and reported that, for soil extracts (using acetone-HCl as the extractant), decarboxylation and unsaturation losses occur at about 280°C. Ioselis et al (1985), also observed the decomposition of carboxylic, phenolic, carbonyl and alcoholic groups in HS at about 300°C.…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

“…The HS fractions (~10 mg) were placed in platinum crucibles and heated continuously from 25°C to 900°C under nitrogen atmosphere (gas flow 50 cm 3 min -1 ). A heating rate of 10°C min -1 was chosen based on previous studies (Ioselis et al, 1985;Campanella and Tomassetti, 1990;Esteves and Duarte, 1999).…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

“…Usually, it is used to characterize the decomposition and thermal stability of materials under a variety of conditions and to examine the kinetics of physicochemical processes occurring in the sample (Hatakeyama and Quinn, 1999). In HS studies, TG has been applied both to quantify the moisture and ash contents (Huffman and Stuber, 1985) as well as to observe and characterize structural changes in the material during heating (Ioselis et al, 1985;Campanella and Tomassetti, 1990;Picollo and Stevenson, 1994). Due to the intrinsic molecular complexity of these materials, however, the interpretation of the thermal curves and related processes is not yet completely clear.…”

Section: Introductionmentioning

confidence: 99%

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Elemental compositions, FT-IR spectra and thermal behavior of sedimentary fulvic and humic acids from aquatic and terrestrial environments

Giovanela¹,

Parlanti²,

Soriano-Sierra³

et al. 2004

Geochem. J.

101

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Studies on elemental analysis, Fourier transform infrared spectroscopy (FT-IR) and thermal decomposition (thermogravimetry, TG; and derivative thermogravimetry, DTG) of sedimentary fulvic (FA) and humic acids (HA) from marine, estuarine, lacustrine and terrestrial environments are presented. In general, H/C and N/C atomic ratios, as well as the infrared spectra, reflected the extent of the influence of algal and/or terrestrial organic matter sources on the samples, the aquatic (both, marine and freshwater) humic substances (HS) being richer in nitrogen and more saturated, than terrestrial materials. Comparison of properties of FA and HA from the same parent sediments showed that the latter are relatively richer in nitrogen and unsubstituted aliphatic chains and poorer in carboxylic groups. FT-IR spectra showed that the nitrogen present is mostly as forming part of amide groups. Concerning thermal degradation, two main steps were observed for all samples: the first, relative to the loss of moisture, being located between 40°C and 100°C and the second between 270°C and 440°C. FT-IR spectra of the samples which had been heated to 90°C, 400°C and 900°C showed that, upon heating, the carboxyl content decreases (especially for FA), the aliphaticity decreases and the aromaticity increases (especially for HA), indicating that the 270°C-470°C degradation step might be related to decarboxylation and unsaturation losses. In spite of this, both kinds of HS, were shown to be highly thermo-resistant materials retaining most of their typical original infrared spectral features, even after being heated to 400°C.

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Section: Thermogravimetric Analysismentioning

confidence: 99%

Section: Thermogravimetric Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elemental compositions, FT-IR spectra and thermal behavior of sedimentary fulvic and humic acids from aquatic and terrestrial environments

Giovanela¹,

Parlanti²,

Soriano-Sierra³

et al. 2004

Geochem. J.

101

View full text Add to dashboard Cite

show abstract

“…The progressive loss of weight up to 100°C is due mainly to the loss of sorbed water. According to the results of numerous researchers (Esteves & Duarte, 1999;Ioselis, Rubinsztain, Ikan, Aizenshtai, & Frenkel, 1985;Kretschmann & Peschke, 1994) thermogravimetric studies can be employed to provide evidence for and to characterise structural changes in HS; differences in the thermal decomposition curves may be ascribed to different degrees of humification. Weight losses below 350°C can be considered as the result of thermal decomposition of carbohydrates, carboxylic, phenolic, carbonyl and alcoholic groups of HA and of thermal dehydration of hydroxylated aliphatic structures with the generation of low-molecular weight alcohols.…”

Section: Resultsmentioning

confidence: 99%

Sedimentary humic substances in the northern Adriatic sea (Mediterranean sea)

Calace

Cardellicchio

Petronio

et al. 2006

Marine Environmental Research

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“…The ultrasound application improves appreciably thermal extraction of mercury from dredging sludge with an enhancement of about 25% in temperature range of 470-520 K. As an hypothesis, this result could be explained considering that the ultrasonic particle size reduction of the slurry provides an enhancement of the partial thermal decomposition of humic substances [22], consequently mercury bound to that material reach about 90% of desorption at lower temperature. In any case some authors reported that below 620 K thermal decomposition of aliphatic structures and polysaccharides occurred together with the elimination of functional groups due to the decarboxylation reactions [28,29], therefore thermal desorption of mercury from dredging sludge could take place at the same time. Further investigations are needed to better explain these observations.…”

Section: Thermal Desorptionmentioning

confidence: 98%