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1.
Long-term field experiment was established in 1978 on a coastal paddy soil to determine the effect of application of pig manure, rice straw and chemical N fertilizer on the physical property and humus characteristics of soil. Results showed that the porosity, the microstructural coefficient, the reactivities of organic C and N, the OlogK value, the degree of oxidation stability, the contents of o-alkyl C and alkyl C, and the ratio of aliphatic C to aromatic C of humic acid from soils received organic manure increased; whereas, the ratio of<10μm to >10μm of microaggregates, the humification degree of humus, the degree of organo-mineral complexation, the number-average molecular weight, the C/H ratio, the contents of carboxyl and aromatic C of HAs in them decreased. These results indicated that the application of organic manure not only improved the physical property of the paddy soil but also made the HA more aliphatic in structure and younger in origin.  相似文献   

2.
We characterized humic acids (HAs) and glycerol-extractable organic fractions (GEOFs) extracted from four Andisols, taken from comparable soil-climate conditions on the east side of Mount Etna. The soils were formed on old lava (about 9 000 years ago), old tephra (about 8 700 years ago), recent lava (about 2 600 years ago) and recent tephra (about 3 600 years ago). A part of the organic matter of the soils, deprived of HAs and fulvic acids (FAs), was isolated by glycerol extraction. The GEOF can not be extracted with alkaline solutions, probably because it is closely bound to the mineral component of the soil. The characterization of the extracted organic fraction was carried out using elementary and functional group analysis and Fourier transform infrared (FT-IR) spectroscopy. About 20 extractions were necessary to extract the HA and FA from the older soils and about 10 extractions to extract them from the younger soils. Data showed that the GEOFs had a greater ash content and a smaller N content, as well as a greater presence of aliphatic compounds and carboxylic groups as compared to the HA extracted from the same soil. The GEOFs extracted from younger soils also had a lower yield, ash and COOH-group content, and were more aliphatic than the GEOF extracted from older soils. Finally, the GEOFs were more closely bound to the amorphous component of the soil (‘short-range’ minerals) and consequently less subject to biodegradation.  相似文献   

3.
聚环氧琥珀酸对污泥中镉的萃取作用   总被引：3，自引：0，他引：3  
Polyepoxysuccinic acid (PESA), as an environmental benign biodegradable chelant, was used to remove heavy metals from the sewage sludge of Shanghai Taopu Wastewater Treatment Plant. The extraction of cadmium (Cd) from sewage sludge using aqueous solution of PESA was studied. It was found that PESA was capable of extracting Cd from the sludge, and the extraction efficiency was dependent on both pH and the concentration of the chelating reagent. The extraction efficiency decreased gradually with increasing of pH, whereas the dependency on pH decreased as the concentration of PESA increased. In the case of the high PESA to total metal ratio, e.g., 10:1, the extraction efficiency reached above 70% within the pH range from 1 to 7. The highest extraction efficiency obtained in the experiment was 78％. By comparing the contents of the heavy metals in sewage sludge before and after the extraction, it was found that the extracted Cd came mainly from the four fractions: acid-soluble, reducible, oxidizable, and water-soluble fractions.  相似文献   

4.
PESA对污泥中铬的萃取研究   总被引：1，自引：0，他引：1  
An environmentally benign biodegradable chelant,polyepoxysuccinic acid(PESA),was used to separate heavy metals from sewage sludge from the Shanghai Taopu Wastewater Treatment Plant,China,based on chemical extraction technology.The extraction of chromium(Cr) from sewage sludge with an aqueous solution of PESA was studied under various conditions.It was found that the extraction of Cr using PESA was more efficient than that using ethylenediaminetetraacetic acid(EDTA) and S,S-ethylenediaminedisuccinic acid(EDDS) under similar conditions.PESA was capable of extracting Cr from the sewage sludge,and the extraction efficiency was obviously dependent on both the pH and the concentration of the chelating reagent.The extraction efficiency decreased gradually with increasing pH,and the dependence on pH decreased as the concentration of PESA increased.The extraction efficiency reached 58% under conditions of pH = 4 and a ratio of PESA to total heavy metals of 10:1.The extraction efficiency was maintained above 40% within the pH range from 1 to 7 at the high ratio of PESA to total heavy metals of 10:1.Comparing the contents of heavy metals in the sewage sludge before and after the extraction,it was found that the extracted Cr came mainly from the reducible and oxidizable fractions.  相似文献   

5.
Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of Al and Fe in stabilizing organic matter in volcanic ash soils,we assessed various extraction methods of Al,Fe,and C fractions from montane volcanic ash soils in northern Ecuador,aiming at elucidating the role of Al and Fe in stabilizing soil organic matter(SOM).We found extractions with cold sodium hydroxide,ammonium oxalate/oxalic acid,sodium pyrophosphate,and sodium tetraborate to be particularly useful.Combination of these methods yielded information about the role of the mineral phase in stabilizing organic matter and the differences in type and degree of complexation of organic matter with Al and Fe in the various horizons and soil profiles.Sodium tetraborate extraction proved the only soft extraction method that yielded simultaneous information about the Al,Fe,and C fractions extracted.It also appeared to differentiate between SOM fractions of different stability.The fractions of copper chloride-and potassium chloride-extractable Al were useful in assessing the total reactive and toxic Al fractions,respectively.The classical subdivision of organic matter into humic acids,fulvic acids,and humin added little useful information.The use of fulvic acids as a proxy for mobile organic matter as done in several model-based approaches seems invalid in the soils studied.  相似文献   

6.
高岭石,蒙脱石和针铁矿对泥炭腐殖酸的吸附和分离   总被引：6，自引：0，他引：6  
Sorption of humic acid (HA) on mineral surfaces has a profound interest regarding the fate of hydrophobic organic contaminants (HOCs) and carbon sequestration in soils. The objective of our study is to determine the fractionation behavior of HA upon sorption on mineral surfaces with varying surface properties. HA was coated sequentially on kaolinite (1:1 clay), montmorillonite (2:1 clay), and goethite (iron oxide) for four times. The unadsorbed HA fractions were characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and solid state 13C nuclear magnetic resonance spectroscopy (NMR). The mineral-HA complexes were characterized by DRIFT. Polarity index [(N+O)/C] revealed higher polarity of the unadsorbed HA fractions after coating on kaolinite, reflecting that relatively higher polarity fractions of HA remain unadsorbed. Sorption of aliphatic alcohol fraction along with carbohydrate was prominent on kaolinite surface. DRIFT results of the unadsorbed HA fractions indicated more sorption of aliphatic moieties on both kaolinite and montmorillonite. DRIFT results of the unadsorbed HA fractions after sorption on kaolinite and goethite showed the sorption of the proteinaceous fractions of HA. The HA fractions obtained after coating on goethite showed significant sorption of carboxylic moieties. The results mentioned above comply reasonably well with the DRIFT spectra of the mineral-HA complexes. 13C NMR results showed higher sorption of anomeric C on kaolinite surface. Higher sorption of paraffinic fraction was observed on montmorillonite. NMR data inferred the sorption of carboxylic moieties on goethite surface. Overall, this study showed that aliphatic moieties of HA preferentially sorbed on kaolinite and montmorillonite, while carboxylic functional groups play a significant role in sorption of HA on goethite. The sorbed fractions of HA may modify the mineral surface properties, and thus, the interaction with organic contaminants.  相似文献   

7.
The effect of application of pig manure (PM) on the structural characteristics of humic acids (HAs) of brown soil was studied in field and incubation experiments.The results showed that the number-average molecular weights (Mn),the ratios of C/H,C/H and O/C,the contents of carboxyl and phenolic hydroxyl groups,the content of aromatic C,the values of E2,E4 and λExmax of HAs all decreased;whereas,the contents of alkyl C and O--alkyl C,the ratio of carboxyl to phenolic hydroxyl groups,the degree of oxidation stability,te absorption intensity at 285mμ (UV),and 2920cm^-1 of HAs increased after the application of PM.The above results indicated that the molecular structure of HAs tended to be more aliphatic and simpler after the application of PM.  相似文献   

8.
In this paper,the nitrogen forms in newly-formed humic substances,including humic acid (HA),fulvic acid (FA) and humic acid in humin (HAI),were studied by using the ^15N CP-MAS NMR technique in combination with chemical approaches.Results show that the majority of nitrogen in HA,FA and HAI was in the amide form with some presented as aliphatic and/ or aromatic amines and some as pyrrole type nitrogen,although the contents of nonhydrolyzable nitrogen in them differed greatly from each other (15-55%).  相似文献   

9.
The Zhongdian swamp meadow in Zhongdian, China is well known as “Shangri-la”, where the peat has never been studied for its potential to interact with pollutants. Humic acid (HA) was extracted from Zhongdian peat using two methods, namely sodium pyrophosphate extraction (SPE) and dilute base extraction (DBE), and characterized for its functional groups and sorption property. The HAs extracted by both methods contained several active functional groups and had large external specific surface areas. The adsorption mechanism of methylene blue onto HAs was interpreted as Langmuir sorption. SPE-HA showed higher sorption capacity because of its larger specific surface area, whereas the extraction yield of DBE-HA was twice that of SPE-HA. Kinetics modeling indicated that the sorption of methylene blue was a two-component first order reaction. The component with the higher rate constant also showed higher sorption capacity. No pH effect was observed for methylene blue sorption on HA in our experimental design, and the sorption decreased as the temperature increased.  相似文献   

10.
The effects of soil water regime and soil reaction on nitrogen distribution and fractional composition of newly-formed humus (decayed products) and the structural characteristics of the newly-formed humic acids(HAs) were studied in an incubation experiment,with the following results obtained: 1.The humus newly formed under submerged conditions was higher in the relative content of α-amino acid-N and the humic acid/fulvic acid (HA/FA) ratio than that under upland conditions.The HAs extracted from the former were also higher in C/O ratio,aromaticity and the contents of methoxyl groups and lignin-like components,but lower in the content of carboxyl groups than the HAs from the latter. 2.Under upland conditions,the C/ organic N ratio and the relative content of mobile HA of newly-formed humus were lower,but the HA/FA ratio was higher in the CaCO2-amended treatment than in non-amended treatment.The presence of CaCO3 also resulted in a decrease of C/N ratio of HA and a slight increase of its carboxyl group content.On the other hand,there was no significant change in the composition and properties of the newly-formed humus with the addition of CaCO3 under submerged conditions. 3.Compared with soil HAs,the newly-formed HAs contained more carbohydrates,polypeptides and lignin-like components,and were in lower degrees of oxidation and humification.  相似文献   

11.
连续提取对土壤腐殖质组分数量与特性的影响   总被引：3，自引：1，他引：3  
张晋京  宋祥云  窦森 《土壤通报》2007,38(3):452-456
以暗棕壤为供试土壤,研究了NaOH和NaOH+Na4P2O7连续提取对土壤腐殖质组分数量和特性的影响。结果表明:用两种提取剂得到的土壤腐殖质组分总量相差不大,并且其中HA组分的数量均高于FA组分。随提取次数增加,胡敏酸(HA)、富里酸(FA)和胡敏素(HM)的绝对数量均下降,HA、FA的相对数量也下降,而HM的相对数量则增加。以NaOH为提取剂时,最后得到的腐殖质组分中FA的相对比例高于HA;而用NaOH+Na4P2O7为提取剂时,最后得到的腐殖质组分中HA的相对比例则高于FA。连续提取过程中,HA、FA的色调系数(Δlogk)和活化度(AD)通常呈增加趋势,而相对色度(RF)下降,说明后提取出的HA、FA的缩合度较低,脂族性较强。用RF来表征HA、FA特性变化更为合适。  相似文献   

12.
Tandem size-exclusion chromatography and polyacrylamide gel electrophoresis were used for obtaining stable fractions of different molecular sizes and electrophoretic mobilities from chernozem humic acids (HAs). The obtained fractions were analyzed using solid-phase 13C NMR. The tendencies of the changes in the aromatic and aliphatic components of the HA fractions with different molecular sizes and electrophoretic mobilities were experimentally revealed. The aromatic-to-aliphatic carbon ratio Carom (165–108 ppm)/Caliph (108-0 ppm) was used for comparing the degrees of aliphaticity and aromaticity of the HA macromolecules. This ratio increased by more than five times when going from the high-molecular-weight to the low-molecular-weight fractions and largely determined their hydrophilic properties. The obtained results can be useful for the interpretation of the structural organization and the ecological functions of soil HAs and their fractions.  相似文献   

13.
Aim of our study was the development of the methodological basis for the characterization of humic fractions of a long‐term field experiment. Humic acids (HAs) were extracted from three layers of a nontilled soil using three different extractants (1 M NaOH, 0.1 M Na4P2O7, 1 M Na2CO3), and the humin fraction was enriched. NaOH as extractant for FTIR analysis of humic substances yields higher resolved IR spectra, especially in the important regions of stretching vibrations including aromatic and aliphatic groups and in the fingerprint area including amides, aliphats, and aromats than the other extractants. The NaOH extraction has lower extraction yields as compared to Na4P2O7 and Na2CO3 and represents a different part of the soil organic matter (SOM). This is reflected by lower C : N ratios and higher E4 : E6 and fulvic acid–to–humic acid ratios as compared to the other extractants. The FTIR band areas of HA fraction obtained by NaOH showed an increase of the aromatic and carbonyl groups and a decrease of amide groups with increasing soil depth. Aliphatic groups showed contradicting results: The bands of the stretching vibrations increased, and the band of the bending vibrations decreased. We assume that band interactions in the bending vibrations were responsible for that phenomenon under the assumption of an increase of aliphatic groups with increasing soil depth. The IR bands of the enriched humin fraction showed a decreasing trend in case of both aliphatic bands deriving from stretching vibrations and an increase of aromatic characteristics with depth. Our study led to the conclusion that HA fractions obtained by 1 M NaOH represent a small and dynamic fraction indicated by the measured yields in combination with values of Nt, C : N, E4 : E6 ratios, and ratios of fulvic acids (FA) to HA. The humin fraction has a high contribution to the total organic C and represents a more stabilized fraction of SOM which still shows changes in its aromatic and aliphatic characteristics with soil depth.  相似文献   

14.
The structure of humic acids (HAs) in zonal soil types—soddy-podzolic soils (two samples), gray forest soil (one sample), and chernozems (two samples)—was quantitatively studied by 13C NMR spectros-copy. In the series considered, the content of unsubstituted carbon in the aromatic fragments of HAs increased, and the fraction of unsubstituted aliphatic structures decreased. HAs of soddy-podzolic soils were found to be enriched with carbohydrate fragments compared to HAs of chernozems and gray forest soil. The carbon skeleton of HAs from typical rich chernozem contained significantly more aliphatic and carbohydrate fragments compared to typical chernozem, which probably reflected the lower degree of HA transformation in rich chernozem.  相似文献   

15.
土壤腐殖质分组研究   总被引：22，自引：1，他引：22  
采用Pallo法对两种耕地土壤腐殖质进行分组,初步研究了各组分的数量和结构特征。结果表明:焦磷酸钠提取的胡敏酸(HAp)是胡敏酸(HA)的主要组分;游离富里酸(FAf)是富里酸(FA)的主要组分;胡敏素(HM)的主要组分为非溶解性胡敏素(ISHM),而溶解性胡敏素(SHM)含量较低。通常随土层深度增加,HA、HM各组分的绝对数量和相对数量都下降;FA各组分的绝对数量也下降,而相对数量增加;HA/FA比值下降。一般来看,焦磷酸钠提取的富里酸(FAp)、氢氧化钠提取的富里酸(FAs)比相应的HAp、氢氧化钠提取的胡敏酸(HAs)的分子结构简单,铁结合胡敏素(HMi)比粘粒结合胡敏素(HMc)的分子结构简单;随土层深度增加,HAp、HAs的分子结构变简单,而HMi、HMc的分子结构变复杂。  相似文献   

16.
Preparations of humic acids (HAs) were isolated from a gray forest soil by sequential alkaline extraction. From a sample of 500 g, HA preparations of 2.24, 0.23, and 0.20 g were obtained from the first, second, and third alkaline extracts, respectively. The structure of the preparations was determined by 13C NMR spectroscopy. At each next extraction step, the portion of aliphatic fragments in the HA preparations increased and the content of aromatic structures decreased. The conclusion was drawn that a single extraction is sufficient for obtaining a representative HA sample.  相似文献   

17.
To investigate the chemical heterogeneity of humic acids (HAs), we applied two-dimensional (2-D) electrophoresis to HAs from a compost and two types of soils. In this method, HAs are first separated by isoelectric focusing (IEF) and then separated by polyacrylamide gel electrophoresis (PAGE). IEF and PAGE were carried out in the presence of 7?M urea. Upon 2-D electrophoresis of HAs, dark-colored substances were spread out across the gel mainly in the isoelectric point (pI) range of 3.0–4.5. Green fluorescence was observed in the smaller molecular size region of the gel, especially in the pI range of 3.0–4.5, and the most intense fluorescence was found at the moving front. The gels were divided into 36 sections, and then HA constituents were extracted from the individual sections and recovered by precipitation with acid. The distribution of organic carbon (C) among the gel sections coincided with that of the dark-colored substances on the gel. The total C recoveries were only 43–50%, suggesting that a considerable amount of HA constituents was lost during the extraction from the gels and purification. High-performance size-exclusion chromatography confirmed that the constituents of HAs were separated based on their molecular sizes by PAGE. The measurement of diffuse reflectance infrared Fourier transform (DRIFT) spectra indicated that the chemical properties of the HA constituents differed depending on the position on the gels and were affected by the molecular size rather than the pI. The fractions of the compost HA were characterized by higher proportions of aliphatic, proteinous and polysaccharide moieties and by the presence of lignin-derived structures. For the soil HAs, the fractions were characterized by a high proportion of the carboxyl group and a low proportion of aliphatic moieties. The proportion of proteinous and polysaccharide moieties in the fractions of soil HAs decreased with decreasing molecular size. The chemical properties of the green fluorescent substances remained unclear, since there was not enough of the substances to measure the DRIFT spectra. The present study showed that 2-D electrophoresis in the presence of concentrated urea offers an effective method for fractionating and isolating the constituents of HAs.  相似文献   

18.
Phenanthrene sorption by compost humic acids   总被引：4，自引：0，他引：4  
Nonlinear isotherms were observed for sorption of polycyclic aromatic hydrocarbons (PAHs) to humic materials, but the exact sorption mechanism is not clearly understood. This study aimed to investigate the sorption of PAHs by compost humic materials. Humic acids (HAs) were progressively extracted from two compost samples by a 0.1-M sodium pyrophosphate solution. Sorption of phenanthrene by the extracted HAs was studied with a batch equilibration technique. Competitive sorption between pyrene and phenanthrene in the HAs was also examined. Elemental analysis and solid-state 13C NMR were used to characterize HAs. All sorption isotherms were nonlinear although these samples contained little black carbons if any. Isotherm linearity increased with increasing number of extractions. Isotherm nonlinearity was negatively related to HA aliphaticity. Addition of pyrene to the phenanthrene-HA system increased isotherm linearity. Competition between phenanthrene and pyrene sorption was more pronounced in the first fraction of HAs with a higher content of aromatic moieties. This study showed that humic materials alone could lead to nonideal sorption for PAHs.  相似文献   

19.
Because of its insolubility, heterogeneity and structural complexity, humin is the least understood among the three fractions of soil humic substances. This research aimed to evaluate the long‐term effect of combined nitrogen and phosphorus (NP) fertilizer addition on the chemical structure of humin under maize (Zea mays L.) monoculture in a Typic Hapludoll of northeast China. Soil samples were collected 12 and 25 years after the initiation of the fertilizer treatment. Soil humin was isolated using NaOH‐Na4P2O7 extraction to remove humic and fulvic acids, which was followed by HF‐HCl treatment to remove most of the inorganic minerals. Solid‐state 13C cross‐polarization magic angle spinning nuclear magnetic resonance (13C CPMAS NMR) spectroscopy was used to characterize the chemical structure of the humin isolates. Results showed that the organic carbon (C) content of humin increased after NP fertilizer addition, compared with a no‐fertilizer (CK) treatment. 13C CPMAS NMR indicated that O‐alkyl C and aromatic C of humin decreased, while alkyl C and the ratios of alkyl C/O‐alkyl C, aliphatic C/aromatic C and hydrophobic C/hydrophilic C all increased in the NP fertilizer treatment. The long‐term application of NP fertilizer changed the molecular structure of soil humin to be more alkyl and hydrophobic, and was thus beneficial to the sequestration and stability of organic C in soil.  相似文献   

20.
长施马粪对暗棕壤团聚体腐殖质数量和质量的影响   总被引：2，自引：0，他引：2  
运用元素和红外光谱分析研究了暗棕壤长期施用马粪(每3年施肥1次)、施低量化肥和马粪配施高量化肥对水稳性大团聚体(2 mm和2~0.25 mm)、微团聚体(0.25~0.053 mm)和粉/黏粒粒级(0.053 mm)中腐殖物质-胡敏酸(HA)的分布及其结构特征的影响,探讨施肥对农田土壤肥力的贡献及其团聚体的固碳机制。施用马粪和马粪配施高量化肥分别提高(49.06%)和降低(31.04%)了2~0.25 mm大团聚体比例,3种施肥措施均提高了土壤有机碳(SOC)数量,但对土壤HA数量影响不显著。不同施肥措施对不同粒级团聚体中HA的分子结构特征影响不同,3种施肥措施均降低了2~0.25 mm大团聚体HA的缩合度,芳香性增加;微团聚体HA缩合度降低,脂族性增强;施用马粪提高了粉/黏粒HA的缩合度和脂族性,马粪配施高量化肥提高了粉/黏粒HA的缩合度和芳香性,施用低量化肥,粉/黏粒HA缩合度下降,芳香性提高。因此,长施马粪提高了土壤SOC数量,促进2~0.25 mm大团聚体的形成,大团聚体中HA的稳定性提高,利于土壤固碳,而0.25~0.053 mm微团聚体和0.053 mm粉/黏粒HA的活性增强,利于土壤肥力供给,这些团聚体是评估长施马粪对腐殖质质量产生影响的重要粒级。  相似文献   

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