EFFECT OF SOIL ORGANIC MATTER OXIDATION ON THE COLLAPSE OF VERMICULITE

1985 ◽  
Vol 65 (3) ◽  
pp. 593-597 ◽  
Author(s):  
N. M. MILES ◽  
M. SCHNITZER ◽  
C. R. DE KIMPE
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Key Words ◽  
Mixed Layer ◽  
Ir Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Matter Oxidation ◽  
Ir Spectrophotometry ◽  
Complete Collapse

Oxidation of organic matter with H2O2 produced substantial amounts of NH3 which was then fixed by vermiculite, causing partial or complete collapse and converting the mineral to a mica-like product. The collapse of the mineral was indicated by shifts in the 001 spacing from 1.476 to 1.030 nm and the appearance of a well-defined band at 1430 cm−1 in the IR spectrum, indicative of the presence of NH4+ in the interlayer positions of the clay. Our data suggest that: (a) the transformation of vermiculite to mica during H2O2 oxidation may result in underestimation of the vermiculite content of soils by XRD, and (b) the wide occurrence of mixed-layer minerals in soils may in part have resulted from the fixation of NH3 liberated from the microbial mineralization of organically bound N. Key words: Ammonia, X-ray diffraction, IR spectrophotometry, mixed-layer minerals, H2O2 pretreatment

Influence of soil organic matter on sulfate retention in two Podzols in Quebec, Canada

1999 ◽  
Vol 79 (1) ◽  
pp. 103-109 ◽  
Author(s):  
F. Courchesne ◽  
J.-F. Laberge ◽  
A. Dufresne
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Ammonium Oxalate ◽  
X Ray Diffraction ◽  
Weighted Mean ◽  
Fine Silt ◽  
Mineral Horizon ◽  
Organic C ◽  
X Ray

The role of soil organic matter (OM) on SO4 retention was investigated by comparing OM content, SO4 retention, and the distribution of Fe, Al and Si compounds in OM-poor (Grands-Jardins, PGJ) and OM-rich (Hermine, HER) Podzols from Québec, Canada. At both sites, four pedons were sampled by horizon; soil pH in H2O, organic C, phosphate-extractable SO4 and, sodium pyrophosphate, acid ammonium oxalate and dithionite-citrate-bicarbonate (DCB) extractable Fe, Al and Si were measured for each mineral horizon. The mineralogy of the clay (<2 µm) and fine silt (2–20 µm) fractions of selected horizons was determined by X-ray diffraction (XRD) and infrared spectroscopy (IR). Weighted mean organic C and pyrophosphate extractable Fe and Al contents were significantly higher in the HER than in the PGJ sola, while the PGJ soils were richer in amorphous inorganic Al. No trends were observed for inorganic Fe compounds. Chemical dissolution and IR allowed the identification of short-range ordered aluminosilicates, probably allophane, in the OM-poor and slightly acidic to neutral PGJ soils. These materials were absent from the OM-rich and acidic HER soils. Phosphate extractions showed that the weighted mean native SO4 content was five times higher in the PGJ than in the HER soil. Finally, native SO4 was strongly related to inorganic Fe, Al and Si (associated with allophane) at PGJ but only to inorganic Fe at HER. These results indicate that OM indirectly affects SO4 sorption through the influence organic substances exerts on the nature and distribution of pedogenic Fe, Al and Si compounds, such as allophane, in Podzolic profiles. Key words: Organic matter, sulfate, imogolite, allophane, silica, Podzol

scholarly journals N-octane catalytic isomerization with aluminium and aluminiumlanthanum pillared nontronite

Cerâmica ◽  
2015 ◽  
Vol 61 (360) ◽  
pp. 420-427
Author(s):  
C. P. de Moura ◽  
M. V. S. Fernandes ◽  
L. R. D. da Silva ◽  
L. C. G. Vasconcellos ◽  
R. F. do Nascimento ◽  
...  
Keyword(s):  
Organic Matter ◽  
Diffraction Data ◽  
Pillared Clay ◽  
X Ray Diffraction ◽  
Y Zeolite ◽  
X Ray ◽  
Catalytic Isomerization ◽  
Organic Matter Oxidation

Abstract Nontronite samples pillared with aluminium (Pt/Al-PilM) and aluminium-lanthanum (Pt/AlLa-PilM) were prepared from natural nontronite, characterized and tested as catalyst in n-octane hydroisomerization reaction. The results were compared with those obtained from the same reaction using commercial Y-zeolite impregnated with platinum (Pt-Y). Experiments with commercial zeolite show that platinum is essential to maintain the reactional selectivity of the products. The conversion capacities of (Pt/Al- PilM) and (Pt/AlLa-PilM) were 70% and 40%, respectively, surpassing the Pt-Y performance of 30%, but with the same selectivity. X-ray diffraction data show that organic matter oxidation followed by cationic homogenization is of paramount importance for pillared clay preparation.

scholarly journals Characterization of Ferrihydrite-Soil Organic Matter Coprecipitates by X-ray Diffraction and Mössbauer Spectroscopy

2008 ◽  
Vol 42 (21) ◽  
pp. 7891-7897 ◽  
Author(s):  
Karin Eusterhues ◽  
Friedrich E. Wagner ◽  
Werner Häusler ◽  
Marianne Hanzlik ◽  
Heike Knicker ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Clay Minerals and Organic Matter from Deeply Buried Ordovician-Silurian Shale in Western Iraq: Implications for Maturity and Hydrocarbon Generation

2020 ◽  
pp. 3006-3023
Author(s):  
Ali I. Al-Juboury ◽  
Mohammed A. Al-Haj ◽  
Adrian Hutton ◽  
Brian Jones
Keyword(s):  
Organic Matter ◽  
Clay Minerals ◽  
Mixed Layer ◽  
Oil And Gas ◽  
Vitrinite Reflectance ◽  
Hydrocarbon Generation ◽  
X Ray Diffraction ◽  
Gas Generation ◽  
X Ray ◽  
Organic Mineral

The present work is conducted on the Paleozoic (Ordovician) Khabour and the (Silurian) Akkas shales in the Akkas-1 well of western Iraq. The study is aiming to determine the implications of clay mineral transformation, organic mineral distribution and maturity of hydrocarbon generation, using X-ray diffraction (XRD), scanning electron microscopy (SEM) in addition to organic matter concentrations. In the shale of the Khabour Formation, amorphous organic matter is common and includes various Tasmanite-type organic matter, vitrinite, inertinite, and bituminite. The main clay minerals observed include illite, chlorite, kaolinite, in addition to mixed-layer illite-smectite and rare smectite. In Silurian shale, high content of organic matter is recorded in addition to abundant vitrinite and low content of grainy organic matter (Tasmanites) and pyrite. Illite and kaolinite are commonly found in addition to chlorite and illite-smectite clay minerals. Conversion of smectite to mixed-layer illite-smectite (I-S) and an increase in vitrinite reflectance are commonly observed below 2500 m depth in the studied formations, which coincides with oil and gas generation. These results could be used as an indication of higher maturity and hydrocarbon generation in the deeply buried shale of the Khabour and Akkas formations in western Iraq.

scholarly journals Dissimilatory Iron-Reducing Microorganisms Are Present and Active in the Sediments of the Doce River and Tributaries Impacted by Iron Mine Tailings from the Collapsed Fundão Dam (Mariana, MG, Brazil)

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 244
Author(s):  
Carolina N. Keim ◽  
Jilder D. P. Serna ◽  
Daniel Acosta-Avalos ◽  
Reiner Neumann ◽  
Alex S. Silva ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Magnetic Measurements ◽  
Culture Media ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferric Oxyhydroxide ◽  
Transmission Electron ◽  
Iron Mine ◽  
Organic Matter Oxidation ◽  
Doce River

On 5 November 2015, a large tailing deposit failed in Brazil, releasing an estimated 32.6 to 62 million m3 of iron mining tailings into the environment. Tailings from the Fundão Dam flowed down through the Gualaxo do Norte and Carmo riverbeds and floodplains and reached the Doce River. Since then, bottom sediments have become enriched in Fe(III) oxyhydroxides. Dissimilatory iron-reducing microorganisms (DIRMs) are anaerobes able to couple organic matter oxidation to Fe(III) reduction, producing CO2 and Fe(II), which can precipitate as magnetite (FeO·Fe2O3) and other Fe(II) minerals. In this work, we investigated the presence of DIRMs in affected and non-affected bottom sediments of the Gualaxo do Norte and Doce Rivers. The increase in Fe(II) concentrations in culture media over time indicated the presence of Fe(III)-reducing microorganisms in all sediments tested, which could reduce Fe(III) from both tailings and amorphous ferric oxyhydroxide. Half of our enrichment cultures converted amorphous Fe(III) oxyhydroxide into magnetite, which was characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The conversion of solid Fe(III) phases to soluble Fe(II) and/or magnetite is characteristic of DIRM cultures. The presence of DIRMs in the sediments of the Doce River and tributaries points to the possibility of reductive dissolution of goethite (α-FeOOH) and/or hematite (α-Fe2O3) from sediments, along with the consumption of organics, release of trace elements, and impairment of water quality.

Crystal structures of highly stabilized ylides: methyl(3-methoxy,2-methoxycarbonylbenzoyl) triphenyl- phosphoranylideneacetate and methyl(2-methoxycarb-6-nitrobenzoyl)triphenyl phos phoranyl ideneacetate and the salt methyl(triphenylphosphoranylidene)acetate tetrafluoroborate

1998 ◽  
Vol 76 (12) ◽  
pp. 1844-1852
Author(s):  
Fernande D Rochon ◽  
Robert Melanson ◽  
Margaret M Kayser
Keyword(s):  
Key Words ◽  
Crystal Structures ◽  
Nitro Derivative ◽  
Transient Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ionic Salt ◽  
Higher Temperature ◽  
Cyclic Anhydrides ◽  
Wittig Reactions

At lower temperatures stabilized ylides react with unsymmetrically substituted phthalic anhydrides to give two acyclic adducts. When the reactions are allowed to proceed at higher temperature enol lactones are formed. Identification of the acyclic intermediates was necessary to understand the mechanism of these Wittig reactions. The transient species trapped in the reaction with trimethyloxonium tetrafluoroborate were unambiguously identified by crystallographic methods. The crystal structures of the tetrafluoroborate salt of methyl(triphenylphosphoranyl idene)- acetate (8), methyl(3-methoxy,2-methoxycarbonylbenzoyl)triphenylphosphoranylideneacetate (6β), and methyl(2-methoxycarbonyl,6-nitrobenzoyl)triphenylphosphoranylideneacetate (7α) were studied by X-ray diffraction. The ionic salt (8) is monoclinic, P21c,a= 12.640(5), b = 13.945(9), c = 14.825(6) Å, β = 125.32(3)°, Z = 4, and R = 0.065 (F >5.4 σ(F)). Crystal 6 β is monoclinic, P21c,a = 16.391(16), b = 9.029(6), c = 19.835(19) Å, β = 116.60(6)°, Z = 4, and R = 0.070 (F > 4.6 σ(F)), while crystal 7α is also monoclinic, P21c,a = 9.513(5), b = 9.361(3), c = 30.908(13) Å, β = 98.42(3)°, Z = 4, and R = 0.057 (F >5 σ(F)). In the BF 4- salt (12), the four P-C distances are equal (1.791(5)-1.801(7) Å) with identical tetrahedral angles. For the two triphenylphosphoranylideneacetate compounds, the fourth P-C(1) bond is shorter (1.762(6)-1.734(5) Å) than the three P-C(Ph) bonds (avg. 1.809(5) Å). The angles C(1)-P-C(Ph) are also larger (avg. 112.9(2)° for 6β and 111.9(2)° for 7α) than the C(Ph)-P-C(Ph) angles (avg. 105.8(2)° for 6 β and 106.9(2)° for 7α). These values suggest a multiple nature for the P-C(1) bond. In the nitro derivative, the nitro and the ester groups are disordered equally in positions 2 and 6. Key words: Wittig reactions, cyclic anhydrides, stabilized ylide, phosphoranylidenes, crystal structures.

Synthesis, IR spectrum, thermal behaviour and crystal structure of a novel one-dimensional cyano-bridged zinc(II)/nickel(II) complex

2005 ◽  
Vol 220 (1) ◽  
Author(s):  
Ahmet Karadag ◽  
Hümeyra Pasaoglu ◽  
Gökhan Kastas ◽  
Orhan Büyükgüngör
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Coordination Polymer ◽  
Single Crystal ◽  
Ir Spectrum ◽  
Polymeric Chain ◽  
X Ray Diffraction ◽  
Bimetallic Complex ◽  
One Dimensional ◽  
X Ray

AbstractThe cyano-bridged heteronuclear coordination polymer of zinc(II)/nickel(II) has been prepared by N-(2-hydroxyethyl)-ethylendiamine (hydet-en), alternatively named 2-(2-aminoethylamino)-ethanol and characterised by IR and thermal analysis. In the bimetallic complex, the decomposition of hydet-en ligands is seen to be endothermic whereas that of the cyano ligands is found to be exothermic. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. The crystal structure of the zinc(II)-nickel(II) complex consists of a one-dimensional polymeric chain –Zn(hydet-en)

Structural Studies of Some o- and p-Nitrophenylcarbamates by IR Spectroscopy and X-Ray Diffraction

2008 ◽  
Vol 63 (12) ◽  
pp. 1402-1406
Author(s):  
Monika Simon ◽  
Carol Csunderlik ◽  
G. Jones
Keyword(s):  
Ir Spectroscopy ◽  
Crystal Structures ◽  
Ir Spectrum ◽  
Structural Studies ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray

N-Alkyl-o-nitrophenylcarbamates as solids present two carbonyl stretching bands in the region 1700 - 1800 cm−1 but similar N-alkyl-p-nitrophenylcarbamates have only one such band in the IR spectrum. In solution both kinds of carbamate present one carbonyl stretching band, but for the former, the splittings occur when the carbamates crystallize. Four crystal structures were analyzed by X-ray diffraction. The two ortho derivatives have more than one molecule in the asymmetric unit, which is consistent with the IR observations.

Are mesoionic compounds aromatic?

1998 ◽  
Vol 76 (6) ◽  
pp. 869-872 ◽  
Author(s):  
Alfredo Mayall Simas ◽  
Joseph Miller ◽  
Petrônio Filgueiras de Athayade Filho
Keyword(s):  
Experimental Evidence ◽  
Key Words ◽  
Dipole Moments ◽  
The Other ◽  
Side Chain ◽  
Theoretical Studies ◽  
X Ray Diffraction ◽  
Ring Plane ◽  
X Ray ◽  
Single Bonds

We have evaluated the experimental evidence relevant to the structure and character of mesoionic compounds, accumulated for more than 100 years and including X-ray diffraction studies. We have also evaluated relevant theoretical studies. All these, including our own extensive work, lead us to conclude that mesoionic compounds are not aromatic. According to our recent definition “mesoionic compounds are planar five-membered heterocyclic betaines with at least one side chain whose α-atom is also in the ring plane and with dipole moments of the order of 5 D. Electrons are delocalized over two regions separated by what are essentially single bonds. One region, which includes the a-atom of the side chain is associated with the HOMO and negative π-charge whereas the other is associated with the LUMO and positive π-charge.” Key words: mesoionic compounds, betaines, aromaticity.

scholarly journals SEDIMENTOLOGIA DE LAGUNAS COSTERAS: CIENAGA GRANDE DE SANTA MARTA Y CIENAGA DE PAJARALES

2016 ◽  
Vol 25 ◽  
Author(s):  
Gladys Bernal ◽  
Julliet Betancur
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Chemical Analysis ◽  
X Ray Diffraction ◽  
Caribbean Coast ◽  
X Ray ◽  
Deltaic Plain ◽  
Magdalena River

Ciénaga Grande de Santa Marta and Ciénaga de Pajarales are the two main lagoons of the marginal lagunar system at the deltaic floodplain of Magdalena river, Caribbean coast of Colombia. A systematic surficial sampling was carried out in such lagoons and Salamanca coast. A sporadic sampling was done in other places of the deltaic plain. This paper presents results about grain size, mineralogy, organic matter contents, CaCOa contents, X ray diffraction and chemical analysis of salts for sediments. Sedimentologic charts, distribution schemes and provenience notes are presented.

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