Characterization Of Humic Acids Research Articles

Spectroscopic and microscopic characterization of humic acids from composts made by co-composting of green waste, spent coffee and OMWW sludge

ABSTRACT Due to its important role in the formation of humic acids (HA), improving lignin degradation during composting has usually been considered a challenge. One practice that could stimulate the biodegradation of this recalcitrant molecule is inoculation with exogenous lignolytic fungal strains. Two composts (C1) and (C2) from piles (H1) and (H2) were evaluated. H1 was the control pile and H2 was inoculated at maturity with Trametes trogii, resulting in a 35% increase in lignin degradation rate compared to H1. The aim of this study was to show the main effects of this increase on the humification process in the co-composting of green waste, coffee grounds and olive mill wastewater sludge (OMWWs). Microstructure of HA1 and HA2 extracted from C1 and C2, respectively, was also investigated by scanning electron microscopy (SEM) and SEM coupled with energy-dispersive X-ray spectroscopy (X-EDS). The results showed that there were several similarities between the compost samples tested. These included the mineral content, the degree of polymerization (PD)> 1 and the compact and rigid surface of the extracted HA. However, C2 was characterized by a higher humic content (HC), degree of polymerization (PD), humification index (HI) and percentage of humic acids (PHA) than C1. Carbon-13 nuclear magnetic resonance (13C-NMR) and Fourier transmission-infrared spectroscopy (FTIR) analysis showed that aliphatic groups such as hydroxyls, alcohols and carboxyls were predominant in both composts. SEM analysis in conjunction with X-EDS analysis of HA2 showed a higher proportion of carbon and potassium (18 and 7.93%) than in HA1 (14 and 0.95%).

Efficient recovery and characterization of humic acids from municipal and manure composts: A comparative study

The recovery of humic acids from low-quality compost obtained in municipal solid waste treatment plants provides opportunities for its valorization. This study compares the recovery and properties of the humic acids obtained from municipal mixed waste compost (MMWC) and manure compost. The effects of temperature, time, and KOH concentration on the ratio of humic acids in the extracted liquid and the content of organic carbon of the precipitates were investigated by response surface methodology. Optimal conditions were 30 °C and 24 h for both composts, with a KOH concentration of 0.53 M for MMWC and 0.25 M for manure compost. The manure compost provided a liquid extract richer in humic acids than MMWC (76.6 % vs. 33.7 %), but the precipitates presented similar organic carbon contents (38.1 % vs. 42.4 %). Regarding composition, both humic acids presented higher organic carbon and nitrogen contents than the composts used as feedstock. The extraction and further precipitation of humic acids reduced the concentration of heavy metals. Humic acids from manure compost have a slightly higher average molecular weight (2650 Da) than those from MMWC (1980 Da), while both present similar C/N ratios and degree of aromaticity. Most contaminants of emerging concern present in the original composts were not detected in the humic acids. Thus, it was demonstrated that MMWC constitutes an attractive source of humic acids with properties similar to those obtained from a high-quality compost and, therefore, with potential economic value.

Extraction and characterization of humic acid with high bio-activity by mechanical catalytic treatment

In order to extract humic acid (HA) with high quality from industrial waste weathered coal. The catalyst oxidation for preparation of HA is an environment-friendly and value-added strategy. A green catalyst of α-MnO2/kaolinite (α-MnO2/Kln) was prepared for oxidizing weathered coal for conversion to HA. The effects of ball-milling and catalysis for HA were studied. The catalysts contain oxygen vacancies and lower average oxidation state (3.55), which facilitates the oxidation reaction. Compared to untreated weathered coal HA (WHA), the yield of ball-milling and catalyst treated weathered coal HA (BC/WHA) increased by 18.67%. The catalyst treated weathered coal HA (C/WHA) and BC/WHA displayed better quality, including higher oxygen content (29.90% and 28.68%), increased O/C ratio (0.52 and 0.52), and higher total acidic groups (7.88 and 7.64 meq/g) than those of WHA (25.43%, 0.44, 6.46 meq/g, respectively). The small-molecule fatty acid (79.07%) of C/WHA was obviously higher than that of WHA (66.03%). The active substance of sterols content (19.95%) of BC/WHA increased significantly. These proved the bio-activity of C/WHA and BC/WHA was improved, and α-MnO2/Kln played an effective catalytic oxidation. Overall, BC/WHA has high extraction yield and enhanced bio-activity, making it highly HA output efficient and suitable for agricultural applications.

Geochemical characterization of humic acids isolated from tundra lakes sediments of Murmansk Region

Geochemical characterization of humic acids isolated from tundra lakes sediments of Murmansk Region

Characterization of Humic Acids Isolated from Selected Soils of Livingston Island by CP/MAS 13C NMR and ESR Spectroscopy

The tundra and tundra barrens of the maritime Antarctica represent a unique type of terrestrial ecosystem, geographically confined to the region of the Antarctic Peninsula and a number of surrounding archipelagos. Antarctic soils are underestimated in the quantity of organic matter (OM) pools, organic remnant humification/mineralization rates, and biogenic-abiogenic interactions. The structure of reserves for humic substances within the permafrost zone, as well as the role of the molecular composition of organic substances, are still poorly understood. In this study, we investigate humic acids of selected sub-Antarctic soils in terms of elemental and structural composition to evaluate OM stabilization degree and to assess carbon distributions in the molecules by solid-state CP/MAS 13C NMR and ESR spectroscopy. The results obtained show that the studied humic acids consist mainly of aliphatic structural fragments. According to ESR spectroscopy, it was noted that the most stable molecules by the data of ESR spectroscopy are formed in postornithogenic soils. In contrast, the average portion of the aromatic compounds is about 30% in humic acids, extracted from soils with evident ornithogenic effect.

Extraction and Characterization of Humic Acid Based on Coal Mining Waste

AbstractHumic acid obtained from coal mining waste from the Lenger deposit was studied. Potassium humates were extracted from the raw material using potassium hydroxide. Hydrochloric acid at various concentrations was used for acid sedimentation of humic acids. Experimental data were obtained describing the effect of the HCl concentration and the sedimentation time on the organogenic composition of humic acid and on its acidic characteristics. Organogenic elements, carboxyl groups, and acid values were determined. Fourier transform infrared spectrometry with absorption bands in the range of 4000–600 cm−1, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction analysis were used to characterize the feedstock and the obtained products.

Extraction and Chemical Characterization of Humic Acid from Nitric Acid Treated Lignite and Bituminous Coal Samples

Currently, conversion of coal into alternative fuel and non-fuel valuable products is in demand and growing interest. In the present study, humic acid was extracted from two different ranks of coal, i.e., low rank and high rank (lignite and bituminous), through chemical pretreatment by nitric acid. Samples of lignite and bituminous coal were subjected to nitric acid oxidation followed by extraction using KOH and NaOH gravimetric techniques. The chemical pretreatment of both types of coal led to enhanced yields of humic acid from 21.15% to 57.8% for lignite low-rank coal and 11.6% to 49.6% bituminous high rank coal. The derived humic acid from native coal and nitric acid treated coal was analyzed using elemental analysis, E4/E6 ratio of absorbance at 465 nm and 665 nm using UV-Visible spectrophotometry and Fourier transformed infrared spectroscopy FTIR. The chemical characteristics of coal treated with nitric acid have shown increased molecular weight and improved aromaticity with more oxygen and nitrogen and lower C, H, and sulphur content. The E4/E6 ratio of nitric acid-treated low and high ranks of coal was high. The FTIR spectroscopic data of nitric acid-treated lignite coal indicates an intensive peak of carboxyl group at 2981.84 cm−1, while bituminous coal was shown in cooperation with the N-H group at 2923.04 cm−1. SEM was performed to detect the morphological changes that happen after producing humic acid from HNO3 treatment and native coal. The humic acid produced from HNO3 treated coal had shown clear morphological changes and some deformations on the surface. SEM-EDS detected the major elements, such as nitrogen, in treated humic acid that were absent in raw coal humic acid. Hence, the produced humic acid through HNO3 oxidation showed a more significant number of humic materials with improved efficiency as compared to native coal. This obtained humic acid can be made bioactive for agriculture purposes, i.e., for soil enrichment and improvement in growth conditions of plants and development of green energy solutions.

Humic acid characterization and heavy metal behaviour during vermicomposting of pig manure amended with 13C-labelled rice straw.

Aiming to reveal the humification process of organic waste and its contribution to the heavy metal behaviour affected by earthworm activity, it was studied about the variation of humic acid (HA) and heavy metal behaviour during vermicomposting of the mixed pig manure and 13C-labelled rice straw. The results showed that earthworms could well adapt to the culturing environment and feed organic matter for its growth and reproduction, the vermicomposting process increased the content of humic substances (HS), HA, and fulvic acid (FA) in substrate residues, but led to less transformation of HA into FA. The elemental, ultraviolet absorption spectroscopy, Fourier transform infrared (FTIR) and fluorescence excitation-emission matrix (EEM) analysis indicated that vermicomposting led to more aromatic structures and much higher humification degree in HA, whereas less protein, FA-like substances and plastein in HA. Vermicomposting could enhance the total Cu content and decrease Cu/Zn bioavailability in the substrate residues, and vermicomposting especially can help stabilize Cu in the substrate residues by forming more complexed HA-Cu.

Characterization of humic acids from original coal and its oxidization production

Five coal samples obtained from Chinese coal-producing areas were oxidized by hydrogen peroxide (H2O2), and humic acids (HAs) were derived from original coal and its oxidizition samples. HAs were characterized by physical and chemical methods, between which was also comparison. Yield, ash, aromaticity, molecular weight and functional group of HAs showed variance between original coals. While, yield, molecular weight, and the quantity of oxygen-containing groups of HAs increased more from coals oxidized with H2O2. However, the increase of oxygen-containing functional groups depended on original coals. For Yimin lignite, the oxidation of H2O2 could obviously improve the carboxyl group content of HAs, thus promoting the adsorption of nitrogen. This study demonstrated that oxidation of coal by using H2O2 was one pretreatment way to obtain and modify HAs which could be used as prerequisite and functional material in agricultural field.

Characterization of humic acids produced from fungal liquefaction of low-grade Thar coal

Fungal liquefaction of coal is a promising technology to convert low rank coal into value-added products such as humic acids (HAs) that are extensively used as fertilizer. Use of Pakistani Thar lignite for humic acid extraction can promote agriculture industry in Pakistan. In this study, fifty-five fungal strains were isolated from Thar lignite and screened for their lignite solubilization efficiency. Isolates M13 and MI exhibited highest capacity for lignite solubilization and HA was extracted with 67.4 ± 4.3 percent (w/w) yield. Elemental analysis showed increased nitrogen (0.72–1.39 percent) and oxygen (41.7–48 percent), and decreased carbon (51.8–46.1 percent) and sulphur (1.18–0.73 percent) contents in bio-extracted HA (bHA) compared to chemically extracted HA (cHA). UV/Vis spectroscopy showed increased E4/E6 value from 5.6 ± 0.39 (cHA) to 6.28 ± 0.35 (bHA) indicating reduced molecular mass and aromaticity and increased bioactivity of molecule. FTIR analysis also confirmed these results. HPLC analysis of bHA and cHA showed typical choromatogram of humic acids. Enzyme activity staining indicated the presence of fungal cellulase and xylanase on SDS-PAGE gel. The degradation of lignite macromolecules by lignin degrading fungi is a complex process dependent on alkaline substances, chelators, surfactants and extracellular fungal enzymes.

Extraction and Characterization of Humic Acid from Agriculture Soil and Its Effect on Wheat (Triticum indicum) Seed Growth

Extraction and Characterization of Humic Acid from Agriculture Soil and Its Effect on Wheat (Triticum indicum) Seed Growth

Chemical and spectroscopic characteristics of humic acid from a clay loam soil in Ontario after 52 years of consistent fertilization and crop rotation

Long-term fertilization and crop rotation can influence both organic C sequestration as well as the C composition of soils and the more resistant organic C compounds contained in humic acid (HA). This study examined the effects of fertilization and cropping type (monoculture corn (MC) and Kentucky bluegrass sod (KBS) and corn-oat-alfalfa-alfalfa rotation (RC)) on the HA composition of soil from a 52-year field study in southern Ontario, Canada. Humic acid samples were extracted from soil, and elemental analysis, infrared spectroscopy, solid state 13 C nuclear magnetic resonance spectra, and electron paramagnetic resonance methods were used to determine the influence of the cropping type on the characteristics of HA. Both fertilization and cropping type affected the chemical characteristics of HA. Fertilization led to a 5.9% increase in C, a 7.6% decrease in O, and lower O/C and (N + O)/C ratios in HA as compared to the corresponding non-fertilized treatments. Rotation resulted in a lower proportion of C (48.1%) and a greater (N + O)/C ratio (0.7) relative to monoculture cropping. Infrared spectroscopy analysis showed that HA contained more C-O groups in fertilized soil than in non-fertilized soil under MC and KBS. Fertilization increased the O-alkyl-C, phenolic-C, and free radical contents of HA relative to non-fertilization treatments. Rotation decreased the aliphatic and carboxyl groups and increased the O-alkyl, carbohydrate, aryl, and phenolic groups and free radicals, relative to MC and KBS. Both long-term crop rotation and fertilization dramatically modified the soil HA composition. Significant relationships were observed between the molecular composition of HA and soil organic C. Hence, humic acid characterization could be used as an indicator of the long-term sustainability of crop management practices.

Chemical, Spectral and Morphological Characterization of Humic Acids Extracted and Membrane Purified from Lignite

Chemical, Spectral and Morphological Characterization of Humic Acids Extracted and Membrane Purified from Lignite

Caracterização potenciométrica e reconhecimento de padrões de ácidos húmicos extraídos de solos de altitude

A vegetação de altitude encontrada no topo das montanhas mais altas do Brasil, como os complexos Espinhaço e Mantiqueira, nos estados de Minas Gerais e Bahia, consiste em ecossistemas com características marcantes na diversidade da flora e fauna. O solo nessas áreas é geralmente raso, pobre em nutrientes, mas rico em ferro e alumínio trocáveis.A caracterização dos ácidos húmicos de tais ecossistemas entre outros componentes químicos é muito útil para entender as propriedades fundamentais da composição orgânica do solo.Foram caracterizadospotenciometricamente um total de 72 amostras de solo de 10 locais distintos noscomplexos Espinhaço e Mantiqueira. Os dados das titulações potenciométrica foram processados em um software baseado na linguagem Delphi, a fim de obter as constantes de ionização e as porcentagens dos grupos titulados. Este software demonstrou ser eficiente na reprodução das curvas de titulação com uma concordância notável às experimentais. Após o processamento dos dados potenciométricos, os valores das constantes de ionização e porcentagens dos grupos carboxílicos e fenólicosforam submetidos à análise dascomponentes principais no ambiente MatLab, utilizando uma matriz de 72 amostras e 10 variáveis, obtendo um modelo em que se constatou que as quatro primeiras componentes principais explicavam 91,23% da variação total dos dados originais.A análise das componentes principais mostrou uma separação relativa entre as amostras. As características dos ácidos húmicos evidenciadas pela titulação potenciométrica refletem as condições em que estes ácidos foram formados, embora não permitindo uma separação mais eficaz entre os grupos evidenciados pela análise dascomponentes principais.

Humic acid characterization in soil from various land uses in Tutur District, Pasuruan Regency of East Java

Changes in land use will impact on the characteristics of humic acid in the soil due to biotic and abiotic factors. The study aimed to characterize humic acid in soil from various land uses in Tutur District, Pasuruan Regency of East Java. Soil sampling was carried out on six land uses, namely mixed garden, coffee plantation, apple orchard, vegetable garden, pine forest, and conservation forest. Analysis of soil samples included soil chemical characteristics (pH, redox, organic-C, and total-N) and characterization of humic acid included colour ratio of E4/E6, total acidity, carboxyl groups, and phenolic groups. The results showed that the land use of coffee plantation provided the best soil fertility indicated by the contents of humic acid, total-N, organic-C in the soil that were higher than that of other land-uses. The highest humification index was obtained for coffee plantation land use with the measurement of the E4/E6 colour ratio of 4.56 index value. The best characteristics based on the total value of acidity, the -COOH group and the phenolic -OH group were observed in the coffee plantation. This was supported by the characteristic of humic acid through the humification index or E4/E6 colour ratio, as well as the low phenolic -OH value which is a characteristic of fulvic acid.

Doped TiO2 Photocatalysts for the Photocatalytic Degradation Efficiency of Methylene Blue and Humic Acid under Solar Light

I n various advanced oxidation processes, photocatalysis is a promising and efficient way? to remove natural organic matter consisting of humic acids and fulvic acids. The principle of this method involves both usage of a semiconductor photocatalyst and O2 for the generation of radicals. Among them, TiO2 photocatalysis is the most popular and studied one since TiO has unique properties such as being chemically inert, photocatalytically stable, Phone: +90 386 280 3104cheap, non-toxic, environmentally benign and exhibiting high oxidative power. However, despite all the advantages of using TiO2 as a photocatalyst, there is a major disadvantage. Since TiO2 has a broad band gap, its usage widely under solar light is limited and only allows to be active under UV light. Doping is one of the most popular methods to enhance the photocatalytic activity of TiO2 via using metal or non-metal species as dopants. In this respect, solar light sensitive TiO2 photocatalyst, C, N, S, Se doped and S/N codoped TiO2 photocatalysts were synthesized by using wet-impregnation method. These doped photocatalysts were characterized by Raman spectroscopy to determine the crystal surface morphology. Moreover, methylene blue was used to investigate the photocatalytic performance of prepared doped TiO2 photocatalysts in the presence or absence of organic matrix. Photocatalytic experiments were performed using a solar light simulating photoreactor. Humic acid characterization was monitored by UV-vis and fluorescence spectroscopy

Degradation of Humic Acid by Ferrous Ion Activated Persulfate

The persulfate anions (S2O8 2™) can be activated by Fe2+ to produce sulfate radicals (·SO4 −) and hydroxyl radicals (·OH), which can oxidize organic compounds rapidly. Humic acid (HA) is widely found in nature and is the main limiting factor for high-concentration wastewater discharge. In this study, HA was treated by Fe2+/S2O8 2™ system, the effects of initial pH, concentrations of Fe2+, persulfate (PS), and HA on the removal efficiencies of HA and E3/E4 were discussed. Besides UV254 and UV280, we found that UV250, UV270, UV300, UV365, UV400, UV436 and UV465 can effectively quantified the concentrations of HA, providing more HA characterization methods. When the initial pH was 3.0, the concentrations of PS and Fe2+ were 100 mmol/L and 20 mmol/L, respectively, the removal efficiency of HA reached 72% after 5 minutes, indicating that PS/Fe2+ effectively degrade HA, and E3/E4 increased from 2.6 to 5.75, suggesting the molecular weight and aromaticity of HA decreased. The removal efficiencies of HA increased as the concentrations of Fe2+ and PS increased, while the removal efficiencies of HA decreased as the initial concentration of HA increased. The addition of hydroxylamine hydrochloride (HAH) in Fe2+/S2O8 2™ system, could effectively promoted the Fe3+/Fe2+ circulation and reduced the accumulation of Fe3+, and strengthened the removal efficiency of HA. The research results indicate that Fe2+/S2O8 2™ oxidation is a promising technique for the treatment of HA in wastewater.

Characterization of Humic Acid and Fulvic Acid Extracted from Soil Samples of Cultivated Areas of North Bengal and Sikkim States, India

Humic acid and fulvic acid extracted from soils of cultivated areas, collected from Majitar, Darjeeling and Pundibari cities were first isolated, purified and then characterized for the physico-chemical properties (oxidizable organic carbon, electrical conductivity, pH, phosphorus, nitrogen, potassium, CEC, etc.). The physico-chemical studies showed that soils were neutral to acidic but are independent of altitude. Organic carbon, available phosphorus, nitrogen were higher with soil of Majitar city. The total acidity, carboxylic group, phenolic -OH group were higher in fulvic acid than in humic acid. Further, both acids were characterized by potentiometric titration, viscometric measurement, surface tension and spectral analysis. The humification index (E4/E6) of fulvic acid was relatively higher than humic acid. The highest molecular weight of humic acid and fulvic acid were recorded 13645.83 and 1465.54, respectively.

Soil Organic Matter Black Box

Soil Organic Matter Black Box

Chemical and Spectroscopic Characterization of Humic Acids Extracted from Filter Cake using Different Basic Solutions

Filter cake is a valuable by-product generated during the process of making sugar from sugarcane in factories. The purpose of this experiment was to study the effect of different basic solutions on humic acid extraction rate. Chemical and spectroscopic characterization of humic acids extracted from filter cake has also been investigated. In this research, extraction and chemistry of humic acid have been studied in two separate experiments. In the first experiment, humic acid was taken from filter cake using the IHSS reference method in three concentrations (0.5 M, 1 M and 2 M) of KOH and two preparation liquids (water and vinasses) in the laboratory of the School of Environmental Sciences at the University of Guelph. Changes in the extraction rate of humic acid with type and concentration of base solution also were studied. In the second experiment, Fourier transform infrared (FTIR) and 13C NMR were used to examine the chemistry of humic acid extracted from filter cake by 0.5 M KOH solutions (prepared using distilled water and vinasse). The results indicate that the highest extraction rate of humic acid was obtained when the 2 M KOH made from vinasse solution was used. Elemental analysis results, FTIR and NMR analyses as well as the E4/E6 ratio showed that all samples of extracted humic acid had similar chemical characteristics compared to the reference humic acid.