Extraction Of Humic Substances Research Articles

Response of Potassium Humate Extracted from Different Organic Sources on Yield and Quality of Green Chilli

Aim: In recent trend of organic farming, use of humic substances plays important role, as it act as biostimulants to boost the yield of crop. Humic substances can be easily obtained by locally available organic sources. Hence, three different organic sources viz. Farm Yard Manure (FYM), vermicompost, lignite were characterized for their physico-chemical properties and quality parameters along with nutrients to judge their quality and maturity to extract humic substances. The potassium salt of humic acid extracted from these three sources were used as foliar application at different concentrations to study their effects on yield and quality of green chilli. Study Design: The pot culture experiment was conducted in Completely Randomized Design comprising eleven treatments with three replications. Place and Duration of the Study: The experiment was conducted in rabi season 2021-22 at College of Agriculture, Karad, Maharashtra, India. Methodology: Three organic sources viz. Farm Yard Manure (FYM), vermicompost and lignite were used to extract humic substances (humic and fulvic acid). These organic sources were studied for their physico-chemical properties and quality parameters along with their nutrient status to compare their quality and maturity for extraction of humic substances. Humic substances obtained from these different sources were studied for their content and characteristics. The potassium humate extracted from these organic sources were used in a pot culture study on green chilli, comprising eleven treatments and three replications. The different levels of potassium humate (200 to 600 ppm) were used as foliar application on transplanted chilli at 30 and 45 days after transplanting (DAT) along with recommended dose of fertilizers (GRDF) for studying its effects on yield and quality of green chilli. Results: Among all the three organic sources, vermicompost was reported as the best organic source to extract humic substances from its physico-chemical properties viz. pH (6.9), EC (0.3 dS m-1), water soluble organic carbon (0.76 %) and C:N ratio (18.0), which are considered as quality and maturity parameters to obtain good quality humic substances. Nutrient status for macro and micronutrients were reported to be higher in vermicompost followed by FYM and least content in lignite. In the pot culture experiment, the foliar application of potassium humate extracted from vermicompost resulted in significant improvement in fresh and dry yield of chilli fruit and stalk as compared to potassium humate application extracted from FYM and lignite. Among the various concentrations used (200-600 ppm) for the foliar application of potassium humate, application @ 400 ppm extracted from vermicompost along with GRDF (T7) was reported as the best treatment resulting in significantly increase in the fresh and dry yield of chilli fruits and stalk. Further, it was noticed that the same treatment was observed to be effective in significant improvement of the ascorbic acid content as quality parameter in fresh green chilli fruits.

Application of artificial neural network and dynamic adsorption models to predict humic substances extraction from municipal solid waste leachate

Sustainable municipal solid waste leachate (MSWL) management requires a paradigm shift from removing contaminants to effectively recovering resources and decreasing contaminants simultaneously. In this study, two types of humic substances, fulvic acid (FA) and humic acid (HA) were extracted from MSWL. HA was extracted using HCl and NaOH solution, followed by FA using a column bed under diversified operations such as flow rate, input concentration, and bed height. Also, this work aims to evaluate efficiency of Artificial Neural Network (ANN) and Dynamic adsorption models in predicting FA. With the flow rate of 0.3 mL/min, bed height of 15.5 cm, and input concentration of 4.27 g/mL, the maximum capacity of FA was obtained at 23.03 mg/g. FTIR analysis in HA and FA revealed several oxygen-containing functional groups including carboxylic, phenolic, aliphatic, and ketone. The high correlation coefficient value (R2) and a lower mean squared error value (MSE) were obtained using the ANN, indicating the superior ability of ANN to predict adsorption capacity compared to traditional modeling.

Innovative Method of Extraction of Humic Substances from Digested Sludge and Assessment of the Impact of Their on the Growth of Selected Plants

The paper describes a new, proprietary method of HS extraction from digested sewage sludge. HS was extracted using the processes of dissolving organic substances and precipitating mineral micropollutants. The obtained substances were tested by determining their IR spectrum, elemental composition, and content of micropollutants and comparing them with HS obtained using the classical method. Using Phytotestkit, it was shown that HSs isolated from digested sewage sludge contain relatively large amounts of the nutrients necessary for plants (including N and P) and are a good component of a biostimulating substance. The obtained HS contains more ammonium and phosphorus ions. During extraction, inorganic impurities (including heavy metals) are reduced, and the humic product does not contain pathogens, parasites, and their spores. The method is simple, economically justified, and can be used on an industrial scale.

Extraction yield of humic substances from organic materials

At present there is a great advance in the use of organic substances as fertilizers; humic substances are one of them with various forms of extraction. This article evaluates the extraction yield of humic substances (humic acid and fulvic acid) from three raw materials and different basic extractants and acids. In the basic extraction of humic substances, the type of raw material significantly influences, to a p value equal to 5 %. The maximum extraction volumes of humic substances are with garden waste. The fractionation stage of the humic and fulvic acids (acid extraction) depends on the type of basic extractant. The alternative Vermicompost - NaOH - HCl is the most economic and technically feasible, with 38.53 % of extraction yield value of humic acid and 64.90 $/h of gross profit.

PEAT IS AN EFFECTIVE ALTERNATIVE FUEL

The article considers peat as an effective alternative fuel. Its reserves and directions of use in the world and in Ukraine presented and analyzed. The analysis showed that the geological reserves of peat in Ukraine are equivalent to 600 billion cubic meters of natural gas. The main reserves of peat are concentrated in the districts of Polissia. Industrial peat extraction can take place in 12 regions: Volyn, Rivne, Zhytomyr, Kyiv, Cherkasy, Poltava, Sumy, Chernihiv, Khmelnytskyi, Ternopil, Lviv, and Ivano-Frankivsk. It has been shown that, compared to traditional energy carriers, peat fuel has a lower heat of combustion and a fairly high ash content, but during combustion it emits almost no toxic substances and, accordingly, pollutes the environment much less. In home furnaces, peat fuel burned with a higher efficiency than coal, and the ash used as fertilizer. The estimated cost of 1Gj of lower heat of combustion of various types of fuel according to the data of recent years shows a noticeable advantage of peat fuels. The cost of thermal energy obtained from burning 1 ton of peat briquettes is 2 times cheaper than when using coal, 3 times cheaper than gas, and 4 times cheaper than fuel oil. Peat fuel is suitable for use in all types of modern solid fuel combustion devices, which increases the prospect of its implementation on the domestic and foreign fuel markets. The technology for using plant biomass as a filler in peat briquettes and granules developed. Special attention paid to wood, buckwheat husk, sunflower and other grain crops, which have a lower ash content and a higher heat of combustion, the potential of which waste is significant, and the fuel characteristics are able to increase the heat of combustion of composite peat briquettes or peat granules and reduce their ash content. Taking into account that peat used in large quantities as fertilizer for agriculture, a technology developed according to which humic substances first removed from peat for fertilizer, and then biomass added to this peat and a composite peat fuel obtained. This technology involves the integration of technology and extraction of humic substances into the production cycle of a peat briquette plant for the production of composite fuel. The wide implementation of the developed technology of composite peat briquettes at peat briquette factories will allow to increase the production of briquettes by almost 2 times without increasing the consumption of peat raw materials and to produce peat fuel in the range of 0.18-0.2% of geological reserves, which is equivalent to the replacement of more than 1 billion m3 of natural gas. All this allows us to draw a conclusion about the positioning of peat fuel as an effective local type of fuel, which is an alternative to gas and coal.

Use of high-frequency ultrasound to intensify the sorption of humic substances from brines

To intensify the sorption concentration of humic substances from sodium chloride brines, the use of high-frequency ultrasound has been proposed. The optimal parameters of ultrasound were experimentally established as follows: frequency of 11.0–12.0 MHz, sound intensity of 7.5–8.5 W/cm2, and duration of action not less than 2.0 min. Under the action of high-frequency ultrasound as compared to the use of low-frequency ultrasound, the degree of extraction of humic substances from brines with a concentration of sodium chloride of 150 g/l increases from 91.3–93.2% to 97.3–98.2% and from 93.2–95.0% to 98.1–99.0% on wofatit sorbent and diethylaminoethyl cellulose sorbent, respectively. In addition, the effect of high-frequency ultrasound allows quantitatively sorbing humic substances from more concentrated brines (degree of extraction 90%). Moreover, quantitative sorption of humic substances is possible up to a concentration of sodium chloride of 200 g/l and 250 g/l on the wofatit sorbent and diethylaminoethyl cellulose sorbent, respectively. We developed a method for spectrophotometric determination of the content of humic substances in brines with the lower limits of determination of 0.002 mg/l and 0.001 mg/l for humic acids and fulvic acids, respectively.

Ultrasound-Assisted Extraction of Humic Substances from Peat: Assessment of Process Efficiency and Products' Quality.

Results of efficiency of obtaining humic substances (HSs) from peat in traditional alkaline extraction (TAE) and ultrasound-assisted alkaline extraction (UAAE) are presented. The influence of the duration of the process and ultrasound intensity on the efficiency of extraction of humic acids (HAs) and fulvic acids (FAs) extraction was determined. The composition of the fulvic acid fraction was examined depending on the type of eluent used. Fulvic acids were divided into fractions using columns packed with DAX-8 resin. For this process, 0.1 M NaOH and 0.5 M NH3∙H2O were used as eluents. For the quality assessment of specific fulvic acids fractions, spectroscopic methods (UV-Vis and FTIR) were used. Ultrasound had a positive effect on HS extraction efficiency, especially in increasing the amount of a desired hydrophobic fraction of fulvic acids (HPO). However, a negative effect of the excessive prolongation and ultrasound intensity (approximately 400 mW∙cm−2) on the extraction efficiency of HPO eluted with 0.1 M NaOH solution was observed. Using peat as a raw carbon material for the HS extraction process can be used as an alternative industrial application of peat. UAAE may be considered as an alternative method to TAE, which provides a higher efficiency in HS isolation from peat.

Humic Substances Derived From Biomass Waste During Aerobic Composting and Hydrothermal Treatment: A Review

Humic substances (HSs) occupy 80% of organic matter in soil and have been widely applied for soil remediation agents, potential battery materials, and adsorbents. Since the HS extraction rate is very low by microbial degradation in nature, artificial humification processes such as aerobic composting (AC) and hydrothermal treatment (HT) have attracted a great deal of attention as the most important strategies in HS production. This article aims to provide a state-of-the-art review on the development of conversion of biomass waste into HSs based on AC and HT for the first time in terms of mechanisms, characteristics of HSs’ molecular structure, and influencing factors. In addition, some differences based on the aforementioned information between AC and HT are reviewed and discussed in the conversion of biomass waste into HSs in a pioneering way. For biomass waste conversion, a feasible strategy on effective humification processes by combining AC with HT is proposed.

Comparative effects of two humic substances on microbial dysbiosis in the rhizosphere soil where cucumber (Cucumis sativus L.) is grown

AbstractThe extraction of humic substances from weathered coal and peat has been regarded as an effective way to utilize these wastes. However, the effects of humic acid (HA) and sodium humate (HN) (derived from weathered coal and peat, respectively) on soil microbial dysbiosis remain elusive. By virtue of Illumina sequencing and FUNGuild, we investigated the interrelationships between soil microbial communities and potential phytopathogenic fungi, found that merely HA surprisingly (p < 0.05) reduced the relative richness of potential phytopathogenic fungi in contrast to the controls. The relative abundances of potential pathogenic fungi, fungal community structures, network degrees, and the average degrees of potential pathogenic fungi were recognized as the crucial factors for the determination of cucumbers' aboveground biomasses via Random Forest classification. In addition, the aboveground biomasses were significantly (p < 0.05) and negatively related to the relative richness of potential pathogenic fungi. Among the 28 operational taxonomic units (OTU) that played the most important roles in determining the relative abundance of potential phytopathogenic fungi, 3 OTU belonging to the Penicillium and Nocardioides genera were significantly (p < 0.05) more abundant in the HA treatment. Therefore, it was obvious that HA facilitated the growth of beneficial microbes and increased the microbial network complexity, subsequently decreasing the relative abundance of phytopathogenic fungi and consequently increasing cucumbers' aboveground biomasses. The present research not only highlighted the differences between humic substances originating from weathered coal and peat but also indicated the significance of humic substances in regulating microbial communities, suppressing potential phytopathogenic fungi and facilitating cucumber growth.

Antibacterial and antioxidant properties of humic substances from composted agricultural biomasses

BackgroundBioactive components isolated from composted agricultural biomasses have been receiving progressive attention, because they may improve the antibiotic susceptibility of drug resistant bacterial strains. Here, three different humic substances (HS) were isolated from composted artichoke (HS-CYN) and pepper (HS-PEP) wastes, and from coffee grounds (HS-COF), and characterized by infrared spectrometry, NMR spectroscopy, thermochemolysis–GC/MS, and high-performance size-exclusion chromatography. The antibacterial activity of HS was evaluated against some pathogenic bacterial strains, while their bioactivity was determined by a germination assay on basil (Red–Violet variety) seeds.ResultsHS-CYN and HS-PEP exhibited the largest antioxidant activity and most significant antimicrobial capacity against some gram-positive bacterial strains, such as Staphylococcus aureus and Enterococcus faecalis. The same HS determined a significant increase of both root and epicotyls in seed germination experiments. The bioactivity of HS was related not only to their specific molecular composition but also to the conformational stability of their suprastructures. Specifically, the greatest bioactive and antimicrobial properties were related to the largest abundance of hydrophobic aromatic and phenolic components and to a more rigid conformational arrangement, that, in turn, appeared to be related to a small fragmentation degree of lignin structures.ConclusionsOur results showed that extraction of bioactive HS from green composts may be a sustainable and eco-compatible way to valorise agricultural byproducts. HS may be indeed exploited as substrates to produce novel materials not only to improve plant productivity but also for medical applications.Graphical

Efecto de extractos de sustancias húmicas en la germinación y el crecimiento de plántulas de arroz (Oryza sativa L.), cv. INCA LP-5

The use of biostimulants in agriculture is gaining ground in the international context with very promising results for the agriculture sustainability in the new millennium. The objective of the present work was to evaluate the biological activity of humic substances extracts (HSE I) and (HSE II) in the rice crop cv INCA LP-5. An experiment was carried out in the germinative phase: rice seeds were germinated in dilutions of the HSE I and HSE II extracts and the percentage of germination and root and coleoptile length were evaluated 7 days after germination seed (dag). Another in the vegetative phase: rice seeds were imbibed 24 hours in dilutions of HSE I and HSE II, then sowed and were applied by foliar spray dilutions of HSE I and HSE II at 7 and 14 dag, the indicators of plant height and root length were determined at 14 and 21 dag. The extracts of humid substances used have no effect on the percentage of germination of the rice seeds, however the use of dilutions of HSE II promoting the length of the root and coleoptile of the rice seedlings. The effect of foliar application of both HSE was perceptible in the aerial part; in the root only the use of I HSE in the 1:60 dilution was beneficial. Other study will be necessary for the use of I HSE and II in rice cultivation.

Extraction and Spectroscopic Analysis of Humic Substances with the Goal of Recycling Construction Sludge:

Extraction and Spectroscopic Analysis of Humic Substances with the Goal of Recycling Construction Sludge:

Interaction of Pb, Ni and Cd with Aquatic Humic Substances of Amazonian Blackwater Rivers

In this study, the extraction and characterization of aquatic humic substances (AHS) from two blackwater rivers in the Amazon basin was carried out in order to assess the seasonal effects in the AHS structure. In addition, an investigation of the complexing capacities (CC) of the structures containing the metal ions CdII, NiII and PbII was also done. The characterization (of the AHS) was done using UV-Vis, molecular fluorescence, and infrared spectroscopy. AHS from the Negro River showed more aromatic characteristics in its structures and molecular weight, than the AHS from the Caru River. The AHS studied presented a seasonal pattern characterized by higher humification levels during the rainy season. For all the metals, the AHS complexing capacity was higher for the Negro River. The highest complexing capacities were observed for the NiII assays, which were 0.56 and 0.12 µmol NiII mg-1 dissolved organic carbon (DOC), for AHS RN and AHS RC-II, respectively. We concluded that the transport, bioavailability, and toxicity, of these metal species should be higher for Caru River.

TECHNOLOGY FOR PRODUCING HUMIC SUBSTANCES FROM PEAT

Humic acids are the most important component of soil humus. The higher their content, then the soil is fertile. However, in the natural state, humic acids are insoluble in water and little available to plants. They become available only after indirect action - humus mineralization, when it transforms into simple mineral compounds. In nature, more humic acids are found in low-calorie fuels - brown coal, peat and others. For power engineering, humic acids are an undesirable component, fuel with their high content is of low grade. However, for the production of humates - the more of them in the raw material, the better. Chemical activation of peat by treatment with an alkaline solution activates humic acids, which transform into a plastic water-soluble state. Humic substances of peat are both a natural astringent and a fertilizer useful for restoring the humus layer. The classical technology for the extraction of humic substances using chemical methods is based on high temperatures of the mixture and requires a lot of electricity. The proposed mode of extraction of the humus component according to the developed standard procedure takes place at an extraction temperature of 20 ° C, 60 ° C and the duration of treatment with an alkaline solution in a cavitation apparatus for 20 min, 40 min and 60 min. The research was carried out on milled and dry peat. The humic components in the humic substances were determined using a method adapted to our conditions. For the first time, the stage of extraction of humic components of peat, integrated into peat-processing production, made it possible to remove a sufficient amount of humic substances for the production of organic fertilizers. The remainder of the peat after extraction contains a sufficient amount of activated humic substances, which are a binding component for the production of peat briquettes.

Effects of Microbes from Coal-Related Commercial Humic Substances on Hydroponic Crop Cultivation: A Microbiological View for Agronomical Use of Humic Substances.

Here, coal-related humic substances (HSs) were examined to confirm whether sterilization treatments induce their inferior ability to stimulate lettuce in hydroponic cultivations. Interestingly, a drastic reduction in both lettuce biomass and microbial colony-forming units of the crop culture solutions was observed when the autoclaved HSs were treated. Some microbial genera (i.e., Bacillus and Aspergillus) identifiable in the bare HS-treated hydroponic systems were able to be isolated by direct inoculation of bare HS powders on conventional microbial nutrients, supporting that flourishing microbes in the hydroponic cultivations derive from bare HSs-treated. Moreover, coincubation of some isolated bacterial and fungal strains (i.e., Bacillus and Aspergillus genera) from HSs with lettuce resulted in a significant increase in plant biomass and enhanced resistance to NaCl-related abiotic stresses. Microbial volatile organic compounds renowned for plant stimulation were detected by using solid-phase microextraction coupled with gas chromatography-mass spectrometry. It was finally confirmed that the isolates are capable of utilizing carbon substrates such as pectin and tween 20 or 40, which are relevant to those of microbes isolated from peat and leonardite (i.e., HS extraction sources). Overall, our results suggest that microbiological factors could be considered when commercial coal-related HSs are applied in hydroponic crop cultivations.

Технологія комплексної переробки торфу

Every country tries to be independent in everything, first of all it is necessary to have a high level of use of own energy resources. Due to the energy crisis, the transition from traditional energy sources to the integrated implementation of alternatives is relevant. The purpose of the study is complex processing of peat for fuel and extraction of humic substances for fertilizer production. Studies of extraction of humic substances were performed on a laboratory stand EI-10, which reproduces the work of a pulsating dispersant with an active diaphragm. The classical technology of extraction of humic substances using chemical methods is based on high temperatures of the mixture, which requires high energy consumption. It was proposed mode of extracting humic component developed by the standard rules, but changes in temperature and duration of extraction processing in an alkaline solution cavitation device. The use of cavitation in the technology of obtaining humic preparations makes it possible to achieve their high physiological activity, high yield of water-soluble organic substances. Briquetting was used to increase the energy density of solid fuel. Based on the research, the technology of obtaining humic fertilizers from peat was developed. The developed technology allows to be integrated into the existing production of the peat briquette plant and will allow to extract as much as possible humic substances from peat with essential reduction of temperature and extraction time with the subsequent application of liquid fraction as fertilizer.

Plant Biostimulants, Seaweeds Extract as a Model (Article Review)

Plant biostimulants are classified as substances which have increased the positive effects on growth and productivity when applied to plants. Biostimulants are obtained naturally from various economically and environmentally viable sources, The plant biostimulants currently accepted include extracts of seaweed, humic substances (humic acids and fulvic acids), chitin and chitosan derivatives, amino acids, protein hydrolysates and microbes. Seaweed extracts and humic acids are widely studied for their role in plant growth-promotion, Seaweeds have been traditionally used in coastal Europe since time immemorial as fertilizers and soil conditioning agents. Seaweeds belong to Rhodophyta, Chlorophyta and Ochrophyta. Over the past two decades, seaweeds havebeen processed and marketed as seaweed extracts in various formulations for use in agriculture and horticulture. Seaweed extracts are rich in micro and macronutrients, polysaccharides, proteins, poly unsaturated fatty acids, polyphenols, phytohormones, and osmolytes. These compounds elicit multiple beneficial effects in plants, including enhanced seed germination and establishment, overall plant growth and productivity, resistance against biotic and abiotic stresses and increased post-harvest shelf lifeNumerous studies of the beneficial effects of seaweed extracts on crop plants and crop production, yield and productivity have been published.

Characterizing humic substances from a large-scale lake with irrigation return flows using 3DEEM-PARAFAC with CART and 2D-COS

The study was intended to determine whether the composition or distribution of humic substances from lake sediment could be characterized by spectroscopic data with chemometrics methods. The research materials were humic substances extracted from sediment samples collected in heavily polluted areas in Wuliangsuhai Lake. Humic substance extraction was performed using the method proposed by the International Humic Substances Society (IHSS). In extracted humic substances, the three-dimensional excitation–emission matrix (3DEEM) was determined, and parallel factor analysis (PARAFAC) with classification and regression trees (CART) and two-dimensional correlation spectra (2D-COS) was used to analyze spectroscopic data. Both the fulvic acid (FA) and the humic acid (HA) samples had five PARAFAC components (C1–C5), which contained Vis fulvic-like component (C1), Vis humic-like component (C2), UV humic-like component (C3), microbial fluorescent component (C4), and UV fulvic-like component (C5). This indicated the ubiquity of the humic substance components in the environment. For the CART analysis, C1 was the key factor used to differentiate FA and HA, while C1–C4 were the key parameters used to distinguish the humic substance samples in the eight units. Using 2D-COS and hetero 2D-COS, the PARAFAC components were formed with the increasing of sediment depth in the following order: C3 → C2 → C5 → C4 → C1, which suggested that the relatively labile structure appeared earlier than the relatively stable structure with the greater depth of the sediment. The Vis fulvic-like could be a key factor used to discriminate the FA and the HA fractions, while the latent factors of different depths of sediment were not identical. The order of the humic substance formations was Vis humic-like → UV humic-like → Vis fulvic-like → microbial fluorophore → UV fulvic-like.

Humic Substances Extracted from a Bio-stabilized Waste Applying Different Operating Conditions

Humic substances are the major constituents of the organic matter of soils and sediments and were adopted in different industrial applications for their high content of functional groups. Recently, the research interest is focused on the possibility of extract these substances also from organic wastes, such as biowastes. However, an interesting option could be to extract humic substances from other organic stabilized wastes that differently from compost has no further use. Namely, in this study the possibility of extract Humic Acids (HA) from the bio-stabilized waste produced from a Mechanical Biological Treatment plant adopting different maturation durations was evaluated. Furthermore, the effect of the main operating conditions applied during the alkaline extraction of the humic acids was also investigated (i.e. material particle size, liquid–solid ratio, NaOH concentration and extraction time), analysing the elemental composition, the main functional groups content and the optical properties of the extracted HA. The operating conditions that showed to improve the extraction extent were the NaOH concentration and the extraction time. Furthermore, the HA obtained in these specific conditions showed higher functional groups content and aromaticity, in agreement with the characteristics of the commercial HA, allowing to consider these substances for various industrial applications.

Determination of mercury binding forms in humic substances of lignite

Mercury is known for primarily binding organically in lignite and inorganically in coal. The knowledge about the binding forms does not impact the speciation of mercury in the combustion chamber of a power plant. However, the relation between binding forms and release behavior is crucial for modelling the material flow of mercury in the firing process. Oxidizing agents like halogen salts could be added more effectively. There are different analyzing methods like the float-sink-analysis or the sequential leaching to determine the mercury binding forms. Nevertheless, there is no standard procedure for each analyzing method, which allows a comparison. In this work, mercury binding forms in Central German lignite were investigated. Results from thermal treatment of the lignite show a loss of mercury of 87% up to a temperature of 200 °C. The responsible mercury binding form for that release behavior is discussed by using the results of a leaching process for the extraction of humic substances, mercury analyses and simultaneous thermal analyses with mass spectrometry (TG/DSC-MS). The results show that mercury is bound to humic acids with 0.261 mg/kgdry and in humin with 0.735 mg/kgdry. The high mercury affinity of humic substances is noted as the result of chemical binding with functional groups like the carboxyl group, hydroxyl group and thiol group. Compared to the raw sample, a thermally treated lignite (at 200 °C) does not show any thiol group (m/z=48) in ion intensity measurement. This work proves the organic binding form of mercury with humic substances in lignite.