THE EXTRACTION OF ORGANIC MATTER FROM SELECTED SOILS AND PARTICLE SIZE FRACTIONS WITH 0.5 M NaOH AND 0.1 M Na4P2O7 SOLUTIONS

1989 ◽  
Vol 69 (2) ◽  
pp. 253-262 ◽  
Author(s):  
M. SCHNITZER ◽  
P. SCHUPPLI
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acids ◽  
Nmr Spectra ◽  
Attractive Alternative ◽  
Particle Size Fractions ◽  
Molecular Weights ◽  
Naoh Solution ◽  
C Nmr ◽  
Medium Silt

Organic matter (OM) in the Bainsville and Melfort soils, and in coarse clay and medium silt fractions separated from these soils, was extracted under N2 with 0.5 M NaOH and unadjusted 0.1 M Na4P2O7 solutions. pH ranges of the soils and fractions in contact for 24 h with 0.5 M NaOH and 0.1 M Na4P2O7 solutions extended from 12.2 to 12.6 and 9.0 to 9.4, respectively. Slightly greater proportions of the soil-carbon were extracted by 0.5 M NaOH than by 0.1 M Na4P2O7 solution. The differences, however, did not appear to be significant and may vary from soil to soil. The efficiency of extraction and the characteristics of the extracted materials were assessed on humic acids (HAs), which were isolated from the extracts. From the Bainsville soil and fractions, 0.1 M Na4P2O7 solution extracted more high-molecular weight and more deeply colored HAs than did 0.5 M NaOH solution. But HAs extracted from the Melfort soil and fractions had similar molecular weights and colours. 13C NMR spectra showed that HAs extracted by 0.1 M Na4P2O7 solution tended to be more aromatic than HAs extracted by 0.5 M NaOH solution. Well defined solid-state 13C NMR spectra of HAs, containing up to 69.0% ash, could be recorded. Unadjusted 0.1 M Na4P2O7 solution under N2 was found to be an attractive alternative to 0.5 M NaOH solution as an extractant for soil OM. Key words: Humic acids, E4:E6 ratios, IR spectra, 13C NMR spectra, aromaticity

ATTEMPTS TO IMPROVE SOLID STATE 13C NMR SPECTRA OF WHOLE MINERAL SOILS

1988 ◽  
Vol 68 (3) ◽  
pp. 593-602 ◽  
Author(s):  
M. A. ARSHAD ◽  
J. A. RIPMEESTER ◽  
M. SCHNITZER
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Solid State ◽  
Nmr Spectra ◽  
Important Indicator ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Mineral Soils ◽  
C Nmr

This study describes a number of different preparation techniques for recording solid state 13C NMR spectra of whole mineral soils. Removal of paramagnetic Fe3+ improves the quality of 13C NMR spectra of whole soils and of particle size fractions. The C:Fe ratio appears to be an important indicator for obtaining satisfactory 13C NMR spectra of whole soils and fractions separated from them. If the C:Fe ratio is >> 1, the quality of the spectrum will be good; if the ratio is > 1, a reasonable spectrum will be obtained, but if the ratio is < 1, the spectrum will be poor. Organic-matter-rich soil and particle size fractions separated by a flotation technique produce well-defined 13C NMR spectra, typical of humic materials. Reduction of C-enriched fractions with sodium dithionite and stannous chloride improves the spectral resolution. The data presented herein show that satisfactory solid state 13C NMR spectra can be run on untreated soil particle size fractions, non-magnetic portions of whole soils, and fractions enriched in soil organic matter by flotation, especially after chemical reduction. Key words: 13C NMR spectroscopy, paramagnetic mineral separation

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

Effect of extractant and molecular size on the optical and chemical properties of soil humic acids

Soil Research ◽  
1969 ◽  
Vol 7 (3) ◽  
pp. 229 ◽  
Author(s):  
JHA Butler ◽  
JN Ladd
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Humic Acids ◽  
Gel Filtration ◽  
Chemical Properties ◽  
Molecular Size ◽  
Carboxyl Content ◽  
Peptide Bonds ◽  
Molecular Weights ◽  
Amino Acid Contents

Humic acids extracted from soil with sodium pyrophosphate have greater proportions of lower molecular weight material, less acid-hydrolysable amino acid nitrogen contents, but greater carboxyl contents and extinction values (260 and 450 nm) than humic acids extracted subsequently from the same sample with alkali. Humic acids extracted with alkali from fresh soil samples have intermediate values. Extinction values at 260 nm are directly correlated with carboxyl contents for a given soil. Different crop histories have no significant effect on the measured properties of the extracted humic acids. An alkali-extracted humic acid has been fractionated by gel filtration into seven fractions of different nominal molecular weight ranges. As the molecular weights of the fractions increase, both aliphatic C-H (based on infrared absorption at 2900 cm-1) and acid-hydrolysable amino acid contents increase, whereas extinction values at 260 nm and carboxyl contents decrease. The infrared spectra of the high molecular weight fractions have peaks at 1650 and 1510 cm-1 which correlate with acid-hydrolysable amino acid contents and which correspond to amide I and II bands of peptide bonds. Alkaline hydrolysis to split peptide bonds eliminates both these peaks. The spectra also have peaks at 1720 and 1210 cm-1 which correlate with the carboxyl content.

Polymerization of n-butyl methylacrylate using bis(β- ketoamino)nickel(II)/MAO catalytic systems

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaohui He ◽  
Yiwang Chen ◽  
Yongming Liu ◽  
Muqing Chen ◽  
Shuxian Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Moderate Activity ◽  
Polymerization Time ◽  
Catalytic Systems ◽  
Molecular Weights ◽  
Molar Ratios ◽  
Broad Molecular Weight Distribution ◽  
C Nmr

AbstractThe polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(β-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH3]2: R = phenyl, 1; R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn=2.0~3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).

A facile method to prepare methylcellulose from annual plants and wood using iodomethane

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Daiyong Ye ◽  
Xavier Farriol
Keyword(s):  
Hydrogen Peroxide ◽  
Ambient Temperature ◽  
Dimethyl Sulfoxide ◽  
Gel Permeation Chromatography ◽  
Annual Plants ◽  
Molecular Weights ◽  
Gel Permeation ◽  
Key Factor ◽  
Naoh Solution ◽  
C Nmr

AbstractA novel facile method was developed to prepare methylcellulose from miscanthus, cardoon and eucalyptus. Pulps were obtained by the impregnation rapid steam pulping process (IRSP). A total-chlorine-free (TCF) method was used to bleach the pulps with hydrogen peroxide. Bleached pulps were mercerized in 40% NaOH solution for one hour at ambient temperature. Mercerized cellulose reacted with iodomethane in 2-propanol slurry at 60°C for 22 h. Mercerization and methylation were repeated. Intrinsic viscosities of methylcellulose were measured in 4% NaOH solution. Super-molecular substitution patterns of methylcellulose were determined by 13C NMR. Molecular weights of methylcellulose were measured in dimethyl sulfoxide by gel permeation chromatography. Pulping severity is a key factor influencing the properties of the methylcellulose prepared.

HUMIC-FULVIC ACID RELATIONSHIPS IN ORGANIC SOILS AND HUMIFICATION OF THE ORGANIC MATTER IN THESE SOILS

1967 ◽  
Vol 47 (3) ◽  
pp. 245-250 ◽  
Author(s):  
M. Schnitzer
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acid ◽  
Fulvic Acid ◽  
Oxidative Degradation ◽  
Fulvic Acids ◽  
Organic Soil ◽  
Organic Soils ◽  
Salting Out ◽  
Naoh Solution

Twenty organic-soil samples of widely differing degrees of decomposition were extracted with 0.5 N NaOH solution under N2. Amounts of humic and of fulvic acids in the acidified extracts did not correlate significantly with pyrophosphate solubilities. This was thought to be due to interference in the separation scheme by relatively large amounts of ash constituents in the extracts. Since the "classical" fractionation of soil organic matter appears to involve essentially the "salting out" of higher molecular-weight humic from lower molecular-weight fulvic acids, an excessively high salt concentration during the separation should be avoided.To lower the concentration of inorganic constituents in the extracts, the samples were first pretreated with dilute HCl–HF solution and then extracted with 0.1 N NaOH rather than with 0.5 N NaOH. Under these conditions, amounts of fulvic acids in the acidified extracts showed a significant positive correlation (r = 0.52) with pyrophosphate solubilities of untreated extracts, whereas amounts of humic acids in the extracts exhibited a highly negative correlation (r = −0.57) with pyrophosphate solubilities. In the soils examined, increased humification was associated with increases in fulvic-acid but decreases in humic-acid concentrations.From the results of this and of earlier investigations done in this laboratory it appeared that the main mechanism governing humification in these soils was oxidative degradation, resulting ultimately in the formation of fulvic from humic acid.

Copolymerization of 5-norbornene-2-metheneoxy-trimethylsilyl with methyl 5-norbornene-2-carboxylate catalyzed by a novel Ni(benzocyclohexan-ketonaphthylimino)2/B(C6F5)3) system

2012 ◽  
Vol 32 (6-7) ◽  
pp. 415-423
Author(s):  
Xiaofeng Wang ◽  
Xiaohui He ◽  
Defu Chen ◽  
Yiwang Chen
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Nmr Spectra ◽  
Catalyst System ◽  
Narrow Molecular Weight Distribution ◽  
Complex Catalyst ◽  
Good Thermal Stability ◽  
H Nmr ◽  
Catalyst Systems ◽  
C Nmr

Abstract Copolymerization of 5-norbornene-2-metheneoxy-trimethylsilyl [NB-CH2OSi(CH3)3] with norbornene (NB) or methyl 5-norbornene-2-carboxylate (NB-COOCH3) was carried out in toluene by using novel nickel(II) complex catalyst systems, Ni(benzocyclohexan-ketonaphthylimino)2/B(C6F5)3 [Ni(bchkni)2/B(C6F5)3]. The catalyst system showed high activity on the copolymerization of NB-CH2OSi(CH3)3 with NB (2.3–3.3×104 gpolymer/molNi·h) and NB-CH2OSi(CH3)3 with NB-COOCH3(0.5–3.0×104 gpolymer/molNi·h). However, the solubility of copolymers of NB-CH2OSi(CH3)3 with NB and NB-CH2OSi(CH3)3 with NB-COOCH3, which contain 18.7–86.7 mol% of NB-CH2OSi(CH3)3, was too poor to characterize. The achieved copolymers were confirmed to be vinyl-addition copolymers through the analysis of FTIR, 1H NMR, and 13C NMR spectra. The incorporation rate was 8.7–86.7 mol% at a content of 10–90 mol% of the NB-CH2OSi(CH3)3 in the monomer feeds ratios. The obtained ester functionalized NB copolymer containing 8.7–18.7 mol% of NB-CH2OSi(CH3)3 showed a moderate molecular weight (Mw=1.6–6.0×104 g/mol) and relative narrow molecular weight distribution (Mw/Mn=1.6–2.2). Thermogravimetry (TGA) analyses results showed that the copolymers exhibited good thermal stability (Td=330–350°C) and were noncrystalline by WAXD analyses results.

Importance of charred organic matter in Black Chernozem soils of Saskatchewan

2001 ◽  
Vol 81 (3) ◽  
pp. 285-297 ◽  
Author(s):  
E V Ponomarenko ◽  
D W Anderson
Keyword(s):  
Organic Matter ◽  
High Energy ◽  
Humus Formation ◽  
Organic C ◽  
Particle Size Fractions ◽  
Chernozem Soils ◽  
And Storage ◽  
Uv Oxidation ◽  
Products Of Incomplete Combustion ◽  
C Nmr

A combination of both conventional and novel techniques, such as micromorphology, scanning electron microscopy, and high energy ultraviolet photo-oxidation, have been applied to estimate the proportion of charred organic C in Black Chernozem soils in Saskatchewan. Char was represented by products of incomplete combustion of both arboreal and herbaceous vegetation. Char was found in all particle size fractions of A horizons of Black soils. Char was represented by a variety of forms, from fresh and angular, to rounded and clay-coated particles in the silt fraction. It is likely that the surface area and ability to adsorb clay vary with the size and nature of char particles. Sand-sized char includes particles with various surface properties and adsorptive ability. Generally, younger and lighter char with hydrophobic properties appears to be in the clay-sized fractions, whereas the silt contains heavier char particles coated with clay or containing clay in pores. Ultrasound, used to disperse soils, may fracture larger particles to finer sizes. The proportion of organic C in soils and fractions that is resistant to UV-oxidation was as high as 60%, which, based on published guidelines, indicates a very substantial char component in Black soils. CPMAS 13C NMR spectra indicate a strong aromatic peak at 130 ppm, also consistent with the presence of char. Results indicate that char particles as fine as silt size are present in significant amounts in Black soils, suggesting that char is an important component, and indicating the need for a new concept of humus formation and storage in Black soils. Key words: Char, carbon flows, carbon pool, UV-oxidation, fire, soil organic matter

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