Production Of Humic Acids Research Articles

The role of a plant/fungal consortium in the degradation of bituminous hard coal

The sporadic growth of Cynodon dactylon was observed to occur directly on the surface of hard coal in dumps of the Witbank coal mining area of South Africa with the surface coal being broken down into a humic-like particulate material. Microorganism analysis of plants and rhizosphere material from the dumps revealed the presence of arbuscular mycorrhizal fungi and the coal solubilising fungus, Neosartorya fischeri. Studies established to replicate the dump environment revealed increased coal degradation in the form of humic acid production and an increase in small size particles as a result of Cynodon dactylon growth in association with arbuscular mycorrhizal fungi and Neosartorya fischeri. Results suggest that interactions between Cynodon dactylon, arbuscular mycorrhizal fungi, Neosartorya fischeri and other coal-degrading rhizosphere fungi could lead to the degradation of hard coal in situ and that the application of these organisms to discard dumps could be a novel method of coal dump rehabilitation.

Simple and Rapid Method of Isolating Humic Acids from Tropical Peat Soils (Saprists)

Problem Statement: The isolation (extraction, fractionation and purification) of humic acids (HA) from soils is laborious, time consuming and expensive. The extraction, fractionation and purification periods of these substances vary from 12 h-7 days. In order to facilitate production of HA at competitive cost, this study was conducted to investigate whether a simple and rapid procedure could be developed for isolation of HA from well decomposed tropical peat soils (Saprists). Approach: A 0.1 M KOH was used to isolate HA of air dry peat soil at 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 h extraction periods after which samples (liquid obtained after centrifugation at 16,211 G for 15 min) were fractionated (using 6 M HCl) at 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 h. Samples were purified by washing them five times using distilled water instead of using HCl, HF, and an expensive process called dialysis that requires 1 to 7 days to purify HA. Each washing time was 10 min. Standard procedures were used to ascertain the purity (Ash, C, E4/E6, carboxylic, phenolic, total acidity, and K, Ca, Mg, and Na) and quantity of HA yield. Statistical Analysis System (SAS) was used for statistical analysis. Results: Although there was a linear relationship between extraction period and HA yield, there was no relationship between fractionation period and yield of HA. Distilled water used in this study was effective in purifying HA of the Saprists within 1 h without altering the true chemical nature of HA as it significantly reduced the mineral content of HA. Besides, C, E4/E6, carboxylic, phenolic, and total acidity of the isolated HA were typical of standard ones. Conclusion: The isolation of HA from peat soils can be reduced to 9 h (4 h extraction period, 4 h fractionation period and 1 h purification period) instead of the existing range of 1-7 days.

PREPARATION CONDITIONS OF HUMIC ACIDS FROM VILLAGE'S COMPOST FUEL (VCF) AND THEIR EFFECTS ON HUMIC ACIDS CHEMICAL CHARACTERISTIC ALTERNATION DURING ISOLATION PART II. EFFECT OF THE EXTRACTION CONDITIONS ON THE FUNCTIONAL GROUPS CONTENTS OF HUMIC ACIDS AS REVEALED BY SPECTROSCOPIC ANALYSIS

IR spectra of humic acids ( HAs) extracted by NaOH solution under different conditions showed that HAs extracted by 0.1 M after 6h and 16 h have identical finger print regions. These spectra indicate the presence of highest number of functional groups and highest aromatic COOH group content, in comparison with ( HAs) extracted by 0.1M after 2h and 24 h. IR spectrum of humic acids HAs extracted by 0.2M after 2h was generally similar with the two latter spectra. The IR spectra of HAs extracted after 2h by 0.5M, 1M, and 2M not only show the disappearance of aromatic COOH bands but also indicate the hydrolysis of ester moieties and increase the OH groups content of the extracted HAs. The IR spectra of HAs extracted at the latter three concentrations showed attacked finger print regions. Uv-Vis spectra show two clearly observable peaks at 208 and 280 nm which are characteristic to these humic acids. The spectral change of the latter are in agreement with the results obtained by IR analysis According to results obtained, the extraction by 0.1M NaOH after 16h leads to production of HAs of highest condensation, highest functional group content.

Effect of Low‐Rate Commercial Humic Acid on Phosphorus Availability, Micronutrient Uptake, and Spring Wheat Yield

A greenhouse study was conducted to determine the effects of low‐rate commercial humic acid (HA) on phosphorus (P), iron (Fe), and zinc (Zn) availability and spring wheat yields, in both a calcareous soil and a noncalcareous soil. In Phase I, soluble P concentrations were monitored at 1.9, 3.8, and 5.7 cm from a monoammonium phosphate (MAP) fertilizer band that had either been coated with one of two HA products at the equivalent of 1.7 kg HA ha−1, a label rate, or left uncoated. Sampling occurred periodically up to 48 d after fertilizer application. In Phase II, uptake of P, Fe, and Zn and grain yield were measured in soils that had been fertilized with 7.5 or 25 kg P ha−1, either coated with HA or left uncoated. In Phase I, only three significant differences (P=0.05) out of 66 comparisons were found in soluble P concentrations between HA and control treatments at time points ranging from 4 to 48 d after fertilization. In addition, no significant differences were found in nutrient uptake, shoot biomass, or grain yield between HA and control treatments. These greenhouse results suggest that low commercial HA rates (∼1.7 kg HA ha−1) may be insufficient to enhance spring wheat growth.

<![CDATA[<B>A comparative evaluation on the oxidative approaches for extraction of humic acids from low rank coal of Mukah, Sarawak</B>]]>

Humic acid-based products are well marketed; nevertheless, these products remain unpopular in this region possibly due to the higher selling price resulted from the cost imposed on the imported products. For this reason, it is essential to identify the indigenous source of humic acids as the soil conditioner. Abundant of low rank coals are found in Mukah and the non-energy application of the source are largely unexplored. Preliminary study reported that chemical treatment with nitric acid could potentially increase the essential yield of humic acids from 20% to 85%. Nitric acid is an expensive item, which could add on to the cost, hence possibility of employing other oxidative approaches need to be evaluated. In this study, the humic acids were extracted from the low rank coal of Mukah with HNO3, H2O2 and KMnO4 oxidation and were compared in terms of yield, chemical and spectroscopical characteristics. Results indicated that H2O2 oxidation involved considerable weight losses upon oxidation render it unfavorable for production of humic acids. Potassium permanganate oxidation however was not recommended, as a substantial amount of inorganic compounds was introduced to the products and the essential yield generated was low. Nitric acid oxidation remains the choice of the process for extraction of humic acids as the weight losses involved was acceptable; the yield of humic acids obtained was high with characteristics of low ash content and high acidic functional groups.

Reuse of nitric acid in the oxidative pretreatment step for preparation of humic acids from low rank coal of Mukah, Sarawak

Nitric acid is an effective material for production of humic acids. Nevertheless, it is an expensive item that renders the process unfavorable industrially. Study indicated that there was a possibility to reuse the nitric acid for oxidation however the resulting structures of humic acids was not studied. Therefore, the objective of this study was to investigate the chemical and spectroscopic properties of nitrohumic acids prepared with reused nitric acid. The coal sample was oxidized with 5%, 10% and 15% of nitric acid and subjected to extraction for nitrohumic acids. Concentration of nitric acid with the most yields was reemployed for another 2 cycles of oxidation. The chemical and spectroscopic properties of nitrohumic acids were evaluated. The results indicated that oxidation process generally improved the acidic functional properties of the nitrohumic acids with 10% nitric acid producing the most promising yield. The nitric acid was reused for extraction and the percentage yield remained good at an average of 78%. Structurally, the nitrohumic acids produced with the reused nitric acid demonstrated larger molecular size and fewer acidic functional groups suggesting lesser extent of structure fractionation.

Evaluation of oxidation stability of lignite humic substances by DSC induction period measurement

The stability of lignite humic acids and four regenerated humic acids was estimated by employing differential scanning calorimetry. Induction period for the oxidative decomposition of humic matter was calculated from non-isothermal measurements at six different rates of heating. To simulate the gradual evolution history of humic acids, different intensities of oxidation attack by nitric acid on the original lignite was used. Experimental data showed higher stability of natural humic acids in the temperature range where the decomposition step occurred. On the other hand, extrapolation to lower temperatures and calculated kinetic parameters did not correspond to the order observed at higher temperatures. An oscillating trend of calculated parameters of the two proposed parts of stability was observed, which agreed with data concerning regenerated humic acids production. The approach applied in this work represents a rapid and useful method for evaluation of organic matter stability.

Humic substances - compounds of still unknown structure: applications in agriculture, industry, environment, and biomedicine

Humic substances as part of humus-soil organic matter - are compounds arising from the physical, chemical and microbiological transformation (humification) of biomolecules. They are important because they constitute the most ubiquitous source of non-living organic material that nature knows. Approximately 80% of the total carbon in terrestrial media and 60% of the carbon dissolved in aquatic media are made up of humic substances. Humic substances have important roles in soil fertility, and are considered to have primal relevance for the stabilization of soil aggregates. They can be divided into three components according to their solubility: humic acids, fulvic acids and humin. Humic acids are the most explored group of humic substances. Beyond their relevance for life these substances have industrial applications in the development of absorbents to be used at the sources of metal-poisoning. Being natural substances, their purification process is cheaper than the synthesis of any other sorbent and, moreover, due to their high operability, they absorb more than the absorbents used to date, such as active charcoals or clays. The specific properties of humic acid products enable their application in industry, agriculture, environmental and biomedicine.

Formation And Characterization Of Humic Acids From Low Rank Anatolian Coals By Air Oxidation

The results of this study are aimed at evaluating the effects of air oxidation time, temperature and demineralization on humic acid production from two low-rank Anatolian coals. Two Anatolian low rank coals were studied at 120 and 200°C up to 10 days with and without demineralization. The best results for humic acid formation were obtained at a high temperature for longer times. Demineralization effect is negligible for studied coals. The rate of humic acid formation increased at first with increase in oxidation time, reached a maximum, and then decreased at high oxidation time. Also, a detailed study of the elemental composition, the characterization by FTIR, and the acidity of humic acids are reported.

Assessment of the relations between the spectroscopic characteristics of soils and their ability to adsorb organic pollutants

The aim of this research was to study the way the humus content of the soils affects the adsorption of particular organic pollutants. We used five different media during the experiments: two different soils (sandy soil, coherent soil), humic acid extracts extracted from these soils, and a commercially available humic acid product. We studied the adsorbed amount of the given compounds at the particular media, the role of humic materials in the observed adsorption ratios, and whether the co-existence of the different compound changes the adsorption–desorption conditions. The inorganic components of the soils play an important role also in the absorption of the apolar compounds, and as the polarity (or polarizability) of the organic compound increases, the humic materials of the soil, or rather their polar functional groups take the dominant role in the absorption of the pollutant. The absorption and desorption of three apolar compounds were practically not influenced by the presence of other pollutants in the soil, and this phenomenon was also independent from the extracting agent. However, in the case of polar diuron, the presence of other pollutants can result in decrease of mobility.

Production of Humic Acid from Pineapple Leaf Residue

ABSTRACT The study was carried out with the following objectives: (i) to quantify the amount of humic acid (HA) that could be extracted from composted pineapple leaf residue using potassium hydroxide (KOH) produced from pineapple leaf residue, and (ii) to compare the elemental composition, functional groups, and spectral characteristics of HA extracted from composted pineapple leaf using 0.1 M KOH from pineapple leaf and that of analytical grade (0.1 M KOH). The 0.1 M KOH from pineapple leaf residue extracted 20% HA from composted pineapple leaf residue while that of the analytical grade (0.1 M KOH) extracted 30%. The elemental composition (C, H, N, O, and S), functional groups (carboxylic, phenolic OH, and total acidity), and spectral characteristics of the HA extracted using the 2 extractants were generally similar. Potassium hydroxide from pineapple leaves can be used to extract some reasonable amount of HA without appreciably altering the elemental and functional groups constitution as well as the spectral characteristics. The potential of using KOH from pineapple leaf residue in HA studies appears promising.

The reduction of dissolved iron species by humic acid and subsequent production of reactive oxygen species

Humic acid (HA) is distributed throughout the environment. Many of its properties are known, but its exact structure and function are still in question. To understand the chemistry and biochemical implications of HA on living systems we have focused on understanding radical chemistries of HA in the presence of molecular oxygen and hydrogen peroxide. The work presented here uses EPR spectroscopy to demonstrate that Fe(III) is reduced to Fe(II) by peat derived HA (PHA), and that Fe(III) is reduced by PHA more efficiently when bound to chelators. However, desferroxamine (DFOM) sequesters Fe(III) from being reduced by PHA and inhibits the Fenton reaction. The reduction of molecular oxygen by Fe(II) gives H 2O 2 as a significant product. The hydroxyl radical is also produced in this reduction process and is trapped by 5-Diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO). In addition to the formation of H 2O 2 and OH, another oxidant also appears to be present. Although not isolated, this species displays the characteristics of the ferryl ion.

Humic Acids: Marvelous Products of Soil Chemistry

Humic acids (HAs) are remarkable brown to black products of soil chemistry that are essential for healthy and productive soils. Current HA models help to explain HAs' origins and behavior as flexible, aliphatic-aromatic, highly functionalized molecules that can act as photosensitizers, retain water, bind to clays, act as plant growth stimulants, and scavenge toxic pollutants. No synthetic material can match HAs' physical and chemical versatility. Removal of HAs from water avoids disinfection by-products such as chloroform and is a required step in production of potable water. HAs can bind soil toxins along with plant nutrients and they strongly stabilize soils. For these reasons more widespread HA production from composting and future applications of HAs extracted from coal will help to combat water and soil pollution, fight soil erosion, and lessen our dependence on chemical fertilizers.Featured on the Cover

Humic acids from coals of the North-Bohemian coal field: II . Metal-binding capacity under static conditions

The interactions of metal cations (Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Zn) with solid humic acids (HAs) were investigated in a batch arrangement. The sorption of metals on the surface of HAs depends strongly on the pH — sorption decreases with decreasing pH. The metal-binding capacities estimated from the metal–humate binding model range from ca. 0.4 mmol/g (Fe, Ni, Zn) to 1.7 mmol/g (Pb). Of the examined metal cations, Pb 2+ binds most strongly to solid HAs. The order of the metal–humate binding strength is consistent with series found in the literature and is based on the stability constants of metal–humate complexes. In comparison with coal-derived HAs, soil HAs from chernozem (and also low molecular weight HAs) exhibited markedly higher metal-binding capacities, whereas the capacity of oxyhumolite (the raw material for HA production) was lower.

5670345 Biological production of humic acid and clean fuels from coal: Srivastava Kailash Chandra; Walia Daman S Centreville, VA, United States assigned to Arctech Inc

5670345 Biological production of humic acid and clean fuels from coal: Srivastava Kailash Chandra; Walia Daman S Centreville, VA, United States assigned to Arctech Inc

97/05147 Biological production of humic acid and methane from coal: Srivastava, K. C. and Walia, D. S. U.S. US 5,670,345 (Cl. 435-75; C12N1/20), 23 Sep 1997, Appl. 483,261, 7 Jun 1995; 15 pp.

97/05147 Biological production of humic acid and methane from coal: Srivastava, K. C. and Walia, D. S. U.S. US 5,670,345 (Cl. 435-75; C12N1/20), 23 Sep 1997, Appl. 483,261, 7 Jun 1995; 15 pp.

Relationship of soil carbon light fraction, microbial activity, humic acid production and nitrogen fertilization in the decaying process of corn stubble

The variation in stubble decomposition due to fertilizer incorporation was determined in a typical Argiudoll of the Argentinian rolling pampas. The experiment was conducted for 15 years, which included a no till system under maize (Zea mays L.) and a soybean rotation (Glycine max) with 0 and 45kg N ha–1 nitrogen fertilization treatments, called NFS and FS, respectively. A higher proportion of residues with a high N content was found in the FS plots. The different substrate quality proved to be the regulating factor for mineralization. This activity was indicated by the increase in soil microbial activity and soil carbon light fraction in FS compared to NFS. This carbon light fraction mineralizes rapidly but does not contribute to the most stable components, which are related to synthesis and polymerization of humic acids. No significant differences in humic acid content were found.

Adsorption of Aqueous Nucleobases, Nucleosides, and Nucleotides on Compost-Derived Humic Acid. 2. Naturally Occurring Purines

This paper describes adsorption of the aqueous purines adenine (10), adenosine (11), adenosine 5‘-monophosphate (12), guanosine (13), and guanosine 5‘-monophosphate (14) on compost-derived humic acid (HA) over the solute concentration (12−1200 μM) and temperature (10.0−40.0 °C) ranges used with pyrimidine solutes in Part 1. Nucleobase 10 and nucleosides 11 and 13 are neutral under the experimental conditions, while nucleotides 12 and 14 are monoanions. All the purines interact with HA, but only adenine causes HA dissolution at pH 5−6 and temperatures above 25.0 °C, as found with cytosine and (−)nicotine. The IR spectrum of the soluble adenine−HA product indicates strong interaction with carboxylic and phenolic HA groups that is not due to simple proton transfer. Pyrimidines and purines are adsorbed in sequence on three HA sites A, B, and C. Most of the data fit the Langmuir model to generate site capacities vA, vB and vC and equilibrium constants KA, KB, and KC for each solute and site. Average site capacities increase 〈vA〉 < 〈vB〉 < 〈vC〉, while equilibrium constants at 25.0 °C decrease KA > KB > KC. Site capacities vi are independent of temperature and solute molar mass or charge, indicating adsorption through solute nucleobase units. Adenine has unusually high average 〈vA〉 and 〈vB〉 related to its ability to dissolve HA at pH 6, but 〈vC〉 is unexceptional. The equilibrium constant data show that compost-derived HA sites have quite different solute selectivities. For example, site A discriminates poorly between the solutes thymine (4), thymidine (5), and 11 while site C has a strong preference for 4. These selectivities could influence animal, plant, soil, and sediment biochemistry. Linear correlation of the enthalpies and entropies for adsorption of every solute at each HA site points to a common underlying adsorption mechanism.

Etude de la distribution des composés humiques le long de deux profils sédimentaires continentaux

Le couplage des méthodes de fractionnement granulométrique organo-minéral d'un sédiment et de l'extraction alcaline de ses composés humiques a permis d'étudier la répartition à la fois qualitative et quantitative du carbone dans les différentes fractions de la vase de l'étang des Noës (Yvelines) et de la rivière le Réveillon (Val de Marne). La comparaison des deux milieux sédimentaires, biologiquement et texturalement dissemblables, a mis en évidence que les processus d'humification et de minéralisation évoluent spatialement de façon différente, comme en témoigne la dégradation différenciée des matières organiques. Les sédiments de l'étang des Noës présentent une évolution de l'humification vers la profondeur, où l'on constate une forte production d'acides humiques, composés fortement polymérisés. En revanche, dans les sédiments du Réveillon, l'humification, prépondérante dès la strate superficielle, subit un blocage dans la strate profonde qui se traduit par une faible production de composés humiques. La méthodologie employée permet de constater une distribution des substances humiques et de formuler des hypothèses quant à l'évolution des sédiments étudiés.

Solubilized coal as a substrate for biodesulfurization

Problem areas in a multi-step coal desulfurization process were investigated. The process involves mild hot air oxidation, followed by alkaline extraction to separate the resultant humic acid molecules from the insoluble pyrite and ash, and microbial removal of organic sulfur from the solubilized coal molecules. A computer-controlled and -monitored solubilization reactor for humic acid production was constructed. Studies designed to evaluate the physical/chemical nature and solubility characteristics of the humic acids were undertaken, with the ultimate aim of ensuring accessibility of sulfur atoms buried in the interior of these large hydrocarbon macromolecules. One per cent Tween-80 enhanced the solubility of humic acids four-fold. Radiotracer labelled humic acids containing 10.8 × 10 −11 Bq mg −1 of 125I were produced. These labelled humic acids will be used to develop an accurate and dependable assay for microbial organic desulfurization.