Analysis of Structural Features of Humic Acids Fractions after Mechanochemical Modification

2015 ◽  
Vol 1085 ◽  
pp. 3-6 ◽  
Author(s):  
Malika P. Mirzobekzoda ◽  
Elizaveta V. Maltseva ◽  
Natalya S. Shekhovtsova
Keyword(s):  
Chemical Composition ◽  
Ir Spectroscopy ◽  
Humic Acids ◽  
Fulvic Acids ◽  
Structural Features ◽  
Acid Base ◽  
Structural Composition ◽  
Mechanochemical Modification ◽  
The Impact ◽  
First Time

Humic substances are the major components of soil, peat and brown coal. They can be fractionating into fulvic acids (FA), brown humic acids (BHA) and gray humic acids (GHA). In this work we investigated the influence of mechanochemical modifications on structural composition of HAs main fractions using the methods of IR and 1H MRS spectroscopy. The IR spectroscopy results has shown that HA has different chemical composition in comparison with GHA and BHA. Potentiometric titration showed that mechanoactivation (MA) with thiourea increases the amount of oxygen-containing groups up to 2.5. For the first time we studied the impact of modifying agent of thiourea on the structural composition and acid-base properties of HAs major fractions - GHA and BHA during the mechanoactivation process.

scholarly journals Towards a better understanding of the origins, chemical composition and aging of oxygenated organic aerosols: case study of a Mediterranean industrialized environment, Marseille

2013 ◽  
Vol 13 (15) ◽  
pp. 7875-7894 ◽  
Author(s):  
I. El Haddad ◽  
B. D'Anna ◽  
B. Temime-Roussel ◽  
M. Nicolas ◽  
A. Boreave ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Aerosols ◽  
Industrial Emissions ◽  
Aerosol Mass Spectrometer ◽  
Statistical Confidence ◽  
Aerosol Mass ◽  
Novel Approach ◽  
Organic Markers ◽  
The Impact ◽  
First Time

Abstract. As part of the FORMES summer 2008 experiment, an Aerodyne compact time-of-flight aerosol mass spectrometer (cToF-AMS) was deployed at an urban background site in Marseille to investigate the sources and aging of organic aerosols (OA). France's second largest city and the largest port in the Mediterranean, Marseille, provides a locale that is influenced by significant urban industrialized emissions and an active photochemistry with very high ozone concentrations. Particle mass spectra were analyzed by positive matrix factorization (PMF2) and the results were in very good agreement with previous apportionments obtained using a chemical mass balance (CMB) approach coupled to organic markers and metals (El Haddad et al., 2011a). AMS/PMF2 was able to identify for the first time, to the best of our knowledge, the organic aerosol emitted by industrial processes. Even with significant industries in the region, industrial OA was estimated to contribute only ~ 5% of the total OA mass. Both source apportionment techniques suggest that oxygenated OA (OOA) constitutes the major fraction, contributing ~ 80% of OA mass. A novel approach combining AMS/PMF2 data with 14C measurements was applied to identify and quantify the fossil and non-fossil precursors of this fraction and to explicitly assess the related uncertainties. Results show with high statistical confidence that, despite extensive urban and industrial emissions, OOA is overwhelmingly non-fossil, formed via the oxidation of biogenic precursors, including monoterpenes. AMS/PMF2 results strongly suggest that the variability observed in the OOA chemical composition is mainly driven in our case by the aerosol photochemical age. This paper presents the impact of photochemistry on the increase of OOA oxygenation levels, formation of humic-like substances (HULIS) and the evolution of α-pinene SOA (secondary OA) components.

scholarly journals Acid-base adjustments and first evidence of denticle corrosion caused by ocean acidification conditions in a demersal shark species

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jacqueline Dziergwa ◽  
Sarika Singh ◽  
Christopher R. Bridges ◽  
Sven E. Kerwath ◽  
Joachim Enax ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
South African ◽  
Chronic Exposure ◽  
Global Ocean ◽  
Shark Species ◽  
Skin Protection ◽  
Low Oxygen ◽  
Acid Base ◽  
The Impact ◽  
First Time

AbstractGlobal ocean acidification is expected to chronically lower the pH to 7.3 (>2200 µatm seawater pCO2) by the year 2300. Acute hypercapnia already occurs along the South African west and south coasts due to upwelling- and low-oxygen events, with increasing frequency. In the present project we investigated the impact of hypercapnia on the endemic demersal shark species Haploblepharus edwardsii. Specifically, we experimentally analysed acid-base regulation during acute and chronic hypercapnia, the effects of chronic hypercapnia on growth rates and on denticle structure- and composition. While H. edwardsii are physiologically well adapted to acute and chronic hypercapnia, we observed, for the first time, denticle corrosion as a result of chronic exposure. We conclude that denticle corrosion could increase denticle turnover and compromise hydrodynamics and skin protection.

Azide und Cyanamide – ähnlich und doch anders/Azides and Cyanamides – Similar and Yet Different

2003 ◽  
Vol 58 (11) ◽  
pp. 1097-1104 ◽  
Author(s):  
Olaf Reckeweg ◽  
Arndt Simon
Keyword(s):  
Ir Spectroscopy ◽  
Single Crystals ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time ◽  
Raman And Ir Spectroscopy

Abstract The crystal structures of LiN3*H2O (P63/mcm (No. 193), Z = 6; 924.01(13); 560.06(7) pm); NH4N3 (Pmna (No. 53), Z =4; a=889.78(18), b=380,67(8), c=867.35(17) pm); Ca(N3)2 (Fddd (No. 70), Z = 8; a=595.4(2), b=1103.6(5), c=1133.1(6) pm), Sr(N3)2 (Fddd (No. 70), Z =8; a= 612.02(9), b = 1154.60(18), c = 1182.62(15) pm); Ba(N3)2 (P21/m (No. 11), Z = 2; a = 544.8(1), b = 439.9(1), c = 961.3(2) pm, β = 99.64(3)°) and TlN3 (I4/mcm (No. 140), Z = 2; 618.96(9); 732.71(15) pm) have been either determined for the first time or redetermined by X-ray diffraction on single crystals. The afore mentioned compounds, AN3 (A = Na, K, Rb, Cs), M(N3)2 · 2.5 H2O (M = Mg, Zn) and the cyanamides Li2CN2, CdCN2 and CuCN2 were investigated by Raman and IR spectroscopy (KBr technique). Structural features and spectroscopic data of azides and cyanamides from this work and from literature are listed and compared.

scholarly journals New Reduction-Oxidation Indices Applied to Mixtures in the Impact on Seasonal and Circadian Rhythm Studies of The Essential Oil From Leaves of Piper Gaudichaudianum Kunth (Piperaceae) – A Folk Medicine and Ritualistic Plant

2021 ◽  
Author(s):  
Ygor Jessé Ramos ◽  
Claudete da Costa-Oliveira ◽  
Irene Candido-Fonseca ◽  
George Azevedo de Queiroz ◽  
Elsie Franklin Guimarães ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Chemical Composition ◽  
Folk Medicine ◽  
Weighted Average ◽  
Redox Balance ◽  
Phenological Stages ◽  
Composition Variation ◽  
Piper Gaudichaudianum ◽  
The Impact ◽  
First Time

Abstract Piper gaudichaudianum Kunth (Piperaceae) is widely used in Brazil as medicinal and ritualistic. In this study, chemophenetic patterns were evaluated based on leaves’ essential oils (EOs) chemical composition. Several collections were performed to accomplish circadian rhythm and seasonal studies. Besides, a predictive methodology was developed and submitted to Proof of Concept (PoC) to determine the metabolism pattern and evaluate the reduction-oxidation of complex mixtures: Weighted Average Redox Standard (SRO) and General Mixture Redox Index (GMOR). Fresh leaves EOs obtained by hydrodistillation were analyzed by GC-MS and GC-FID. The main identified compounds were sesquiterpenes. Nineteen terpene skeletons were registered. There was chemical composition variation at different phenological stages. EOs varied more between day and night than seasonally. Nine chemotypes are proposed based on our results and those from literature. SRO and GMRO analyzes highlighted a possible redox balance throughout day and night. Compounds per carbon skeleton diversification in EOs are matched by an increase in compounds SRO. We also report for the first time high chemical phenotype plasticity based on EOs analysis and its implications for P. gaudichaudianum chemophenetics, chemosystematics and ecology.

Lithospheric buckling dominates the Cenozoic subsidence of the Qaidam Basin, NE Tibetan Plateau

2021 ◽  
Author(s):  
Hu Xiaoyi ◽  
Wu Lei
Keyword(s):  
Tibetan Plateau ◽  
Qaidam Basin ◽  
Foreland Basin ◽  
Structural Features ◽  
Tectonic Subsidence ◽  
The Tibetan Plateau ◽  
Basin Formation ◽  
Orogenic Belts ◽  
The Impact ◽  
First Time

<p>Flexural basins are the common geological feature in convergent settings, and usually regarded as the result of flexural subsidence of the margins of under-thrusting cratons in response to the gravitational load of over-riding orogens. This process usually causes the fastest tectonic subsidence and thickest orogenic-related deposits in the basin margins adjacent to the orogens, such as India Foreland Basin in front of the Himalaya. The Qaidam Basin, which is the largest sedimentary basin within the Tibetan Plateau interior, was once interpreted to belong to this type and form by flexural subsidence on its south and north margins in response to loading of the Qiman Tagh and the South Qilian Shan orogenic belts, respectively. However, the latest studies present sedimentary and structural features that contrast to a typical foreland basin. These features include (1) depocenters being located along the central axis, rather than the margins, with thickest sediments up to 15 km, and (2) development of many high-angle reverse faults, rather than thin-skinned thrusts, to generate upper-crustal shortening as low as 10-15% (20 – 30 km), indicating that the widths of the orogenic belts juxtaposed atop the basin margins are limited. These features cannot be explained by the flexural subsidence of basin margins and/or sediment load. Herein, we investigate the impact of lithospheric buckling, which has been ignored in most studies of basin formation in compressional settings, on the tectonic subsidence of the Qaidam Basin through numerical simulation based on finite elastic plate model. We first use the flexural backstripping method to calculate the tectonic subsidence of the Cenozoic basement across the Qaidam Basin. And then, we simulate the tectonic subsidence caused by (1) gravitational load of orogenic belts alone, and (2) combined gravitational load and lithosphere buckling. The result shows that the simulated tectonic subsidence curve fits well with the real one only when considering the effect of lithospheric buckling that accounts for >90% tectonic subsidence. Our finding indicates for the first time that lithospheric buckling is also an important mechanism for the subsidence of intramountain basins like the Qaidam Basin, and should not be ignored when studying lithospheric-scale deformation across large orogenic belts.</p>

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 Transformations of phenolic compounds in meadow soils

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anna Ziolkowska ◽  
Bozena Debska ◽  
Magdalena Banach-Szott
Keyword(s):  
Organic Matter ◽  
Chemical Composition ◽  
Phenolic Compounds ◽  
Humic Substances ◽  
Humic Acids ◽  
Plant Material ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids

Abstract The aim of the research has been to determine the role of phenolic compounds in the processes of transformations of organic matter in meadow soils, leading to the formation of humic substances. The research has been performed based on the plant material and soil sampled from Europe’s unique complex of permanent grasslands irrigated continuously for 150 years applying the slope-and-flooding system, the Czerskie Meadows. Phenolic compounds were isolated from the plant material samples (hay, sward and roots) and soils (horizon A, AE and Bsv) and from the fraction of humic and fulvic acids. It was found that the contents of phenolic compounds decrease in the following order: hay > sward > roots > A horizon soil > AE horizon soil > Bsv horizon soil > A horizon fulvic acids > AE horizon fulvic acids > Bsv horizon fulvic acids > A horizon fulvic acids > AE horizon fulvic acids > Bsv horizon fulvic acids. A significantly higher share of cinnamyl than vanillyl and syringyl compounds in the extracts of fulvic acids and slightly higher in the hydrolysates of humic acids confirms the effect of the chemical composition of the plant material undergoing decomposition on the properties of the emerging humic substances.

scholarly journals Role of methyl group number on SOA formation from monocyclic aromatic hydrocarbons photooxidation under low-NO<sub><i>x</i></sub> conditions

2016 ◽  
Vol 16 (4) ◽  
pp. 2255-2272 ◽  
Author(s):  
L. Li ◽  
P. Tang ◽  
S. Nakao ◽  
C.-L. Chen ◽  
D. R. Cocker III
Keyword(s):  
Chemical Composition ◽  
Aromatic Ring ◽  
Aromatic Hydrocarbons ◽  
Methyl Groups ◽  
Methyl Group ◽  
Monocyclic Aromatic Hydrocarbons ◽  
Group Number ◽  
The Impact ◽  
First Time

Abstract. Substitution of methyl groups onto the aromatic ring determines the secondary organic aerosol (SOA) formation from the monocyclic aromatic hydrocarbon precursor (SOA yield and chemical composition). This study links the number of methyl groups on the aromatic ring to SOA formation from monocyclic aromatic hydrocarbons photooxidation under low-NOx conditions (HC/NO  >  10 ppbC : ppb). Monocyclic aromatic hydrocarbons with increasing numbers of methyl groups are systematically studied. SOA formation from pentamethylbenzene and hexamethylbenzene are reported for the first time. A decreasing SOA yield with increasing number of methyl groups is observed. Linear trends are found in both f44 vs. f43 and O / C vs. H / C for SOA from monocyclic aromatic hydrocarbons with zero to six methyl groups. An SOA oxidation state predictive method based on benzene is used to examine the effect of added methyl groups on aromatic oxidation under low-NOx conditions. Further, the impact of methyl group number on density and volatility of SOA from monocyclic aromatic hydrocarbons is explored. Finally, a mechanism for methyl group impact on SOA formation is suggested. Overall, this work suggests that, as more methyl groups are attached on the aromatic ring, SOA products from these monocyclic aromatic hydrocarbons become less oxidized per mass/carbon on the basis of SOA yield or chemical composition.

scholarly journals An integrated chemical and micromorphological investigation of humic substances in three podzolized soils of the Netherlands.

1982 ◽  
Vol 30 (3) ◽  
pp. 205-226
Author(s):  
J. Drozd ◽  
A. Jongerius ◽  
S. Kowalinski
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
The Netherlands ◽  
Humic Substances ◽  
Humic Acids ◽  
Infrared Spectra ◽  
Fulvic Acids ◽  
Low Molecular Weight ◽  
Ap Horizon ◽  
The Stability

The humic substances in a 'Holt' leptic podzol, a 'Haar' humic podzol and a 'Veld' gleyic podzol from the Netherlands were analysed chemically and micromorphologically. The absorption spectra of Na-humates in visible light and infrared spectra were determined for the humic acids. The translocation and distribution of the principal humus compounds occurred by mechanical illuviation in the 'Holt' podzol, and by translocation in solution in the 'Haar' podzol and the 'Veld' podzol. The micromorphological images were closely correlated with the chemical composition of the humic substances. Illuviation cutans occurring in the B horizons of the 'Haar' podzol and the 'Veld' podzol appeared to consist mainly of fulvic acids. The dark humus micro-aggregates characteristic of the 'Haar' podzol and the Ap horizon of the 'Veld' podzol were composed mainly of bitumens, humins and humic acids of high molecular weight, while the brown micro-aggregates of the 'Holt' podzol and the lower horizons of the 'Veld' podzol consisted mainly of fulvic acids and humic acids of low molecular weight. The stability of micro-aggregates was correlated with their composition. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The medium-term effect of natural compost on the spectroscopic properties of humic acids of Czech soils

2018 ◽  
Vol 156 (7) ◽  
pp. 877-887 ◽  
Author(s):  
V. Enev ◽  
L. Doskočil ◽  
L. Kubíková ◽  
M. Klučáková
Keyword(s):  
Functional Groups ◽  
Humic Acids ◽  
Ultra Violet ◽  
Spectroscopic Properties ◽  
Structural Features ◽  
Aromatic Rings ◽  
Degree Of Aromaticity ◽  
Compost Application ◽  
The Impact ◽  
Amended Soil

AbstractIn the current work, humic acids (HAs) isolated from natural compost and unamended and amended soils in a medium-time field experiment were characterized to evaluate the effects of the amendment at rates of 124, 239 and 478 t/ha on their chemical, compositional and structural features. The impact of the application of compost on their properties was observed over 3 years. Humic acids were characterized using spectral methods and elemental analysis. Humic acid isolated from compost was predominantly aliphatic, with a larger content of nitrogen and low degree of aromaticity and humification. The typical maximum (280/345 nm) of HA obtained from compost lies within the T (tryptophan-like) region, which can be ascribed to proteinaceous organic materials. On the other hand, the HAs obtained from amended soil were mainly aromatic in character, with a larger distribution of oxygen-containing functional groups, molecular weight and greater aromaticity. Fluorophores of HAs obtained from amended soil lie within the C (humic-like) region with typical maxima centred in the range 430–450/500–540 nm, occurring usually in HAs isolated from soil, peat and lignite. According to ultra-violet/visible and Fourier-transform infrared (FTIR) spectroscopy, the larger oxygen contents of these HAs are associated with the substitution of aromatic rings by oxygen-containing functional groups such as carboxylic, hydroxyls and ethers. On the basis of FTIR spectra, it was shown that HAs obtained from amended soil 2 and 3 years after compost application were enriched by peptid, aromatic and polysaccharide compounds absorbing at 1540, 1515 and 1040/cm, respectively.

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