Water-soluble Humic Substances Research Articles

LIGNITE AS A RAW MATERIAL FOR THE PRODUCTION OF WATER-SOLUBLE SORBENTS

Large lignite reserves are concentrated in the Dnipro lignite basin of Ukraine. It is profitable to extract it by open-pit mining, as the seams are shallow. Ukrainian lignite is predominantly earthy, subbituminous, which in turn is characterized by a high content of free humic acids. Despite the significant lignite reserves in Ukraine and favourable conditions, its production is insignificant. Most of the lignite is used as fuel, and a small part of it is used as raw material. We have studied the lignite of the Oleksandriya deposit of Ukraine, which contains a large amount (about 80 %) of humic acid, which is the basis to produce effective water-soluble sorbents. The article investigates and determines the efficiency of using lignite from the Oleksandriya deposit to produce humic substances, their elemental composition, and the yield of humic acids from them. The efficiency of the use of humic substances obtained from lignite of the Alexandria deposit in the binding of heavy metal ions (Pb2+, Cd2+) using the method of complexation - ultrafiltration - was determined. The performance of ultrafiltration membranes with a humate solution was determined. The retention coefficient of metal ions, which depends on the concentration of humic substances, was calculated. The conducted studies allow us to assert that the application of the ultrafiltration-complexation method using complexing agents based on humic substances of lignite from the Alexandria deposit can significantly increase the degree of purification of aqueous solutions from heavy metal ions. These studies are relevant and expand the possibilities of using lignite. It has been shown that Ukrainian lignite can be used to produce an environmentally friendly and cheap complexing agent. An important priority for the use of water-soluble humic substances is the large lignite reserves in Ukraine, which can also contribute to improving economic performance. Also, the studies conducted suggest that the application of a combined method that combines ultrafiltration with complexation when using complexing agents based on lignite humic substances can significantly increase the degree of purification from heavy metal ions.

Ammonium Sulfite Slurry from Ammonia-Based Desulfurization Activates Water-Soluble Humic Substances from Lignite: Performance, Application, and Mechanism.

Both ammonium sulfite slurry (ASS) from ammonia-based desulfurization and lignite are waste materials with low value. In this work, an innovative method was developed by applying ASS in lignite activation to produce water-soluble humic substances (WHSs) with a high bioactivity and economic value. The optimal activation method was to mix lignite and ASS at a 4:1-liquid-solid ratio by vortex blender and then oscillate it for 30 min at 25 °C. Compared with that of the unactivated lignite (UAL), the yield of WHSs from activated lignite (AL) increased by 42.72%. WHSs from AL consisted of a large number of aliphatic carbons with low molecular weight and functional groups such as amides, amines, sulfonic acid groups, C-O, and so forth. Moreover, WHSs from AL at lower concentrations (2 mg/L) has a more obvious root-elongation-promoting effect than WHSs from UAL (10 mg/L). Activation experiment with the lignite-related model compounds revealed that ASS caused the breakage of Caliph-O, Caliph-Caliph, and Carom-Caliph linkages between aromatic rings. These findings provide a theoretical basis for the development of green and sustainable technologies for the beneficial reuse of ASS and lignite in agriculture.

Highly humified nitrogen-functionalized lignite activated by urea pretreatment and ozone plasma oxidation

A cost-effective and energy-efficient nitro-humification process (urea pretreatment and ozone plasma oxidation) was developed for nitrogen functionalization and activation of the humic substances (HSs) of lignite. Different nitro-humification metrics, i.e., solubility, physicochemical properties, oxidation degree, nitrogen functionalization, spectral ratios, and surface functionalization, along with energy efficiency and economic profitability, were determined for the processed lignite. The best solubility metrics for the lignite were obtained under 3 wt% ozone, 10 wt% KOH, and 20 wt% urea. The selected conditions could increase alkali- and water-soluble HSs by 2.25 and 2.94 times, respectively, compared with the conventional alkaline extraction method. The process could result in a balanced distribution between nitrogen binding forms. The functionalized lignite showed a 14.5% reduction in the carbon content due to ozone oxidation and an 8.15% nitrogen enrichment due to urea pretreatment, leading to an ideal C/N ratio (5.6%) and a higher O/C ratio (0.94). The humification index (E4/E6 ratio of 6.8) and salt index (46.21%) were acceptable. The process could increase the cation exchange capacity of the lignite by 3.83 times while enhancing its carboxylic and phenolic groups by 215.87% and 85.71%, respectively. The crystallinity index of the processed lignite was increased by 2 times, and the availability of its macro-micronutrients and rare earth elements was increased by 6.35 times and 43.38%, respectively. The nitro-humic products showed lower heavy metals with higher micropores-mesopores in a globular-like and heterogeneous porous structure. The proposed method could increase the process energy efficiency by 59.91% while discounting the production costs by 43%.

Effect of the Conditions of Brown Coal Mechanochemical Treatment on the Composition of Water-Soluble Humic Substances

Effect of the Conditions of Brown Coal Mechanochemical Treatment on the Composition of Water-Soluble Humic Substances

Effect of the Conditions of Brown Coal Mechanochemical Treatment on the Composition of Water-Soluble Humic Substances

Effect of the Conditions of Brown Coal Mechanochemical Treatment on the Composition of Water-Soluble Humic Substances

SPECIAL ASPECTS OF MIGRATION OF WATER-SOLUBLE ORGANIC SUBSTANCE AND BIOGENIC ELEMENTS IN SOD-PODZOLIC SOIL DEPENDING ON FERTILIZATION SYSTEM AND MICROBIAL PREPARATIONS

Objective. To study special aspects of vertical migration of products of biological transformation of organic matter and biogenic elements in sod-podzolic soil under different modes of root nutrition of plants. Methods. Lysimetric experiment, agrochemical, mathematical and statistical. Results. Based on studies conducted in a long-term lysimetric experiment on sod-podzolic soil, periodically washed type of water regime was established, as a result of which 37 mm of moisture, 23 kg/ha of water-soluble humic substances, nitrogen (NO3–) 55 kg/ha, calcium oxide 91 kg/ha and magnesium oxide 26 kg/ha magnesium oxide is lost at the background without inoculation per crop rotation when using mineral fertilization system. The use of microbial preparations reduces the loss of these elements to 33 mm, 20 kg/ha, 52 kg/ha, 83 kg/ha and 25 kg/ha, respectively. It was established that the average infiltration of moisture from the layer 0–155 cm under crops of continuous sowing was 25–37 mm at the background without the use of microbial preparations and 22–33 mm at the background of inoculation. The mineral fertilizer system increased the losses of the soil solution by 9 mm and 7 mm versus the control variants, respective to the backgrounds. The lowest losses of productive moisture were reported in the variants where sidereal fertilizers were used. When replacing the mineral fertilization system with sidereal-mineral and organo-mineral fertilizers without compromising the yield of crop rotations, it is possible to reduce the loss of productive moisture by 1.5 times, reduce the loss of labile soil organic matter by 1.7–1.8 times, nitrate nitrogen by 8–10 %, calcium by 18–24 % and magnesium by 40–50 %. Due to the use of biopreparations, there is a reduction in losses of nitrate nitrogen by 5–18 %, magnesium — by 5–14 %, calcium — by 6–16 %. Conclusion. To reduce non-productive losses of moisture, water-soluble organic matter and biogenic element compounds, it is advisable to use green mass of green manures and microbial preparations at the background of the mineral system and fertilizer system NPK+manure. The use of microbial preparations helps to reduce the loss of nitrate nitrogen by 5–18 %, magnesium — by 5–14 %, calcium — by 6–16 %.

Direct and Indirect Detoxification Effects of Humic Substances

The review summarizes studies on the detoxification effects of water-soluble humic substances (HS), which are products of the natural transformation of organic substances in soils and bottom sediments that serve as natural detoxifying agents in water solutions. The detoxifying effects of HS on microorganisms are quite complex: HS neutralize free pollutants (indirect bioeffects) and also stimulate the protective response of organisms (direct bioeffects). Prospects and potential problems of bioluminescent bacteria-based assay to monitor toxicity of solutions in the presence of HS are discussed. The main criterion for the bioassay application is versatility and ease of use. The detoxification efficiency of HS in different pollutant solutions was evaluated, and the detoxification mechanisms are discussed. Particular attention was paid to the direct and complex direct + indirect effects of HS. The review focuses on the protective function of HS in solutions of radionuclides and salts of stable metals, with special consideration of the antioxidant properties of HS.

Multifunctional Iron–Humic Acid Fertilizer from Ball Milling Double-Shelled Fe–N-doped Hollow Mesoporous Carbon Microspheres with Lignite

Iron (Fe) chelated by water-soluble humic substances can effectively overcome plant micronutrient deficiencies. However, the traditional synthesis methods are often complex, expensive, and thus not...

Molecular Characterization of Water-Soluble Humic like Substances in Smoke Particles Emitted from Combustion of Biomass Materials and Coal Using Ultrahigh-Resolution Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

Water-soluble humic like substances (HULIS) in smoke particles emitted from combustion of biomass materials and coal were characterized by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. The formulas identified were classified into four main groups: CHO, CHON, CHOS, and CHONS. The average H/C and O/C ratios are 1.13-1.33, 1.01-1.13, 1.26-1.48, 1.09-1.24 and 0.21-0.41, 0.27-0.45, 0.41-0.46, 0.44-0.61 for the CHO, CHON, CHOS, and CHONS groups, respectively. The CHO compound was the predominant component (43%-72%) of the smoke HULIS from biomass burning (BB) and coal combustion, followed by the CHON group for BB-smoke HULIS and the S-containing groups (i.e., CHOS and CHONS) for coal-smoke HULIS. These results indicate that the primary HULIS emitted from biomass burning contain a high abundance of CHON species, which appear to be made up mainly of oxidized nitrogen functional groups such as nitro compounds and/or organonitrates. The coal-smoke HULIS contained more compounds with relatively low molecular weight and high aromaticity index (AImod). They were significantly enriched in S-containing compounds with high double bond equivalent (≥4), and O/S ratios suggest that they are most likely made up of aromatic organosulfates and nitrooxy organosulfates that are usually found in polluted atmospheres. These findings imply that the primary emissions from combustion of biomass and coal fuels are potential sources of water-soluble HULIS in an atmospheric matrix and that coal combustion is an especially important source of sulfate compounds.

Pollutant toxicity and detoxification by humic substances: mechanisms and quantitative assessment via luminescent biomonitoring.

The paper considers mechanisms of detoxification of pollutant solutions by water-soluble humic substances (HSs), natural detoxifying agents. The problems and perspectives of bioassay application for toxicity monitoring of complex solutions are discussed from ecological point of view. Bioluminescence assays based on marine bacteria and their enzymes are of special attention here; they were shown to be convenient tools to study the detoxifying effects on cellular and biochemical levels. The advantages of bioluminescent enzymatic assay for monitoring both integral and oxidative toxicities in complex solutions of model pollutants and HS were demonstrated. The efficiencies of detoxification of the solutions of organic oxidizers and salts of metals (including radioactive ones) by HS were analyzed. The dependencies of detoxification efficiency on time of exposure to HS and HS concentrations were demonstrated. Antioxidant properties of HS were considered in detail. The detoxifying effects of HS were shown to be complex and regarded as 'external' (binding and redox processes in solutions outside the organisms) and/or 'internal' organismal processes. The paper demonstrates that the HS can stimulate a protective response of bacterial cells as a result of (1) changes of rates of biochemical reactions and (2) stabilization of mucous layers outside the cell walls. Acceleration of auto-oxidation of NADH, endogenous reducer, by HS was suggested as a reason for toxicity increase in the presence of HS due to abatement of reduction ability of intracellular media.

THE EFFICIENCY OF MICROBIAL PREPARATIONS AT SUGAR SORGHUM CULTIVATION IN POLISSYA REGION

The paper presents the results of lyzimetric and field studies on the impact of microbial preparations Microhumin and Polymyxobacteryn combined with mineral fertilizers on the productivity of sugar sorghum in Polissya region. It was shown that the pre-sowing seeds bacterization had increase crops yields by 5 – 9% and increased output of ethanol by 0.3 t/ha. Application of biological preparations had ensured less reduction of water-soluble humic substances by 28 – 32%, nitrogen (nitrate) – by 11 – 15%, calcium – by 7%, magnesium – by 8 – 15%.

Characterization of Fe–Leonardite Complexes as Novel Natural Iron Fertilizers

Water-soluble humic substances (denoted by LN) extracted at alkaline pH from leonardite are proposed to be used as complexing agents to overcome micronutrient deficiencies in plants such as iron chlorosis. LN presents oxidized functional groups that can bind Fe(2+) and Fe(3+). The knowledge of the environment of Fe in the Fe-LN complexes is a key point in the studies on their efficacy as Fe fertilizers. The aim of this work was to study the Fe(2+)/Fe(3+) species formed in Fe-LN complexes with (57)Fe Mössbauer spectroscopy under different experimental conditions in relation to the Fe-complexing capacities, chemical characteristics, and efficiency to provide iron in hydroponics. A high oxidation rate of Fe(2+) to Fe(3+) was found when samples were prepared with Fe(2+), although no well-crystalline magnetically ordered ferric oxide formation could be observed in slightly acidic or neutral media. It seems to be the case that the formation of Fe(3+)-LN compounds is favored over Fe(2+)-LN compounds, although at acidic pH no complex formation between Fe(3+) and LN occurred. The Fe(2+)/Fe(3+) speciation provided by the Mössbauer data showed that Fe(2+)-LN could be efficient in hydroponics while Fe(3+)-LN is suggested to be used more effectively under calcareous soil conditions. However, according to the biological assay, Fe(3+)-LN proved to be effective as a chlorosis corrector applied to iron-deficient cucumber in nutrient solution.

Dynamic Coating Capillary Electrophoresis for Separation of Humic Acid Using Mixture Solution of Non-ionic Polymers both as Coating Agent and Separation Medium

A simple, rapid, and precise dynamic coating capillary electrophoretic separation method for water-soluble humic substances is proposed. An aqueous solution containing hydroxyethyl cellulose (HEC), polyethylene glycol (PEG), and pH buffer component was employed for both the dynamic coating agent and the separation medium. The procedure for the coating of the capillary inner wall was simply filling the buffered polymer mixture solution into the capillary that had been treated with 1 M aqueous HCl solution. The solution for the capillary coating was directly used as the electrophoretic buffer solution for CE separation. Excellent performance for the separation of humic acid was obtained using the solution containing 0.5% (w/v) HEC, 1.0% (w/v) PEG 10000, and 0.1% (w/v) PEG 8000000. Excellent reproducibility and durability were obtained even at slightly alkaline conditions at pH levels above 8. The separation of 0.1 - 2 kbp of DNA ladder by the proposed method showed was also achieved.

Effects of americium-241 and humic substances on Photobacterium phosphoreum: Bioluminescence and diffuse reflectance FTIR spectroscopic studies

The integral bioluminescence (BL) intensity of live Photobacterium phosphoreum cells (strain 1883 IBSO), sampled at the stationary growth stage (20h), was monitored for further 300h in the absence (control) and presence of 241Am (an α-emitting radionuclide of a high specific activity) in the growth medium. The activity concentration of 241Am was 2kBql−1; [241Am]=6.5×10−11M. Parallel experiments were also performed with water-soluble humic substances (HS, 2.5mgl−1; containing over 70% potassium humate) added to the culture medium as a possible detoxifying agent. The BL spectra of all the bacterial samples were very similar (λmax=481±3nm; FWHM=83±3nm) showing that 241Am (also with HS) influenced the bacterial BL system at stages prior to the formation of electronically excited states. The HS added per se virtually did not influence the integral BL intensity. In the presence of 241Am, BL was initially activated but inhibited after 180h, while the system 241Am+HS showed an effective activation of BL up to 300h which slowly decreased with time. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, applied to dry cell biomass sampled at the stationary growth phase, was used to control possible metabolic responses of the bacteria to the α-radioactivity stress (observed earlier for other bacteria under other stresses). The DRIFT spectra were all very similar showing a low content of intracellular poly-3-hydroxybutyrate (at the level of a few percent of dry biomass) and no or negligible spectroscopic changes in the presence of 241Am and/or HS. This assumes the α-radioactivity effect to be transmitted by live cells mainly to the bacterial BL enzyme system, with negligible structural or compositional changes in cellular macrocomponents at the stationary growth phase.

Carbon and Nitrogen Dynamics in an Oxisol as Affected by Liming and Crop Residues under No-Till

The short-term effects of surface lime application and black oat (Avena strigosa Schreb.) residues, with or without N fertilization, were evaluated in a long-term no-till (NT) system on a sandy clay loam, a kaolinitic, thermic Typic Hapludox from the state of Parana, Brazil. The main plot treatments were: control and dolomitic lime applied on soil surface at 8 Mg ha ―1 . Three treatments with crop residues were evaluated on the subplots: (i) fallow, (ii) black oat residues, and (iii) black oat residues after N fertilization at 180 kg ha ―1 Black oat dry biomass was not affected by the treatments during 3 yr. Surface liming increased soil pH, microbial biomass, microbial activity, and bacterial/ fungal ratio at the soil surface (0-5 cm), resulting in increased amino acid turnover, water-soluble humic substances formation, and N mineralization and nitrification. While the application of black oat did increase the soil pH, overall it had much less effect on soil biological processes and C and N pools than did lime. We concluded that black oat cannot replace the need for lime to optimize crop production in these tropical NT systems. In the long term, however, black oat should aid in the amelioration of acidity and replenishment of soil organic C pools and should help reduce erosion. Overall, this study suggests that overapplication of inorganic fertilizer N may occur in some tropical NT systems. Further experiments are required in NT systems to investigate the use of slow-release N fertilizers in combination with lime and black oat as a mechanism to reduce acidification and promote sustainability.

Binding of anionic surface-active substances by water soluble humic acids

The interaction of anionic SAS with water-soluble humic substances has been studied. The quantitative characteristics of this interaction (binding constants) were calculated and the impact of various factors on the specified interaction was estimated. The binding of anionic SAS by humic substances was found to depend on the contact duration, ambient temperature, concentration, the nature, and size of molecules of humic substances, and also on the nature and length of the hydrocarbon radical of ASAS molecules.

Detoxification of AM-241 solutions by humic substances: bioluminescent monitoring

The study addresses the effect of humic substances on marine luminous bacteria Photobacterium phosphoreum exposed to Am-241 (3,000BqL(-1), water solution). Luminescent intensity of the bacteria was applied as a marker of their physiological activity. Humic substances have been found to reduce the effect of Am-241 on luminescence, decrease damage to cells, and change distribution of Am-241 between bacterial cells and intercellular media. It was shown that water-soluble humic substances, being products of natural transformation of organic substances in soil and bottom sediments, can serve as protecting agents for water microorganisms exposed to alpha radionuclides.

A comparative study of molecular weight distribution of water-soluble humic substances, humic acids, and fulvic acids extracted from sod-podzolic soils

The alteration of organic matter from three sod-podzolic soils in the course of the extraction of water-soluble humic substances was studied by means of size-exclusion chromatography using a combined UV-DOC detector. A comparison of water-soluble humic substances with humic and fulvic acids extracted from the same soils was carried out.

A comparative study of elemental composition of water-soluble humic substances, humic acids, and fulvic acids extracted from sod-podzolic soils

Elemental analysis of water-soluble humic substances extracted from three sod-podzolic soils was carried out. Data on elemental composition were compared to those of humic and fulvic acids extracted from the same soils.

Seasonal variations of concentrations and optical properties of water soluble HULIS collected in urban environments

Abstract. Major contributors to the organic aerosol include water-soluble macromolecular compounds (e.g. HULISWS: Water Soluble Humic LIke Substances). The nature and sources of HULISWS are still largely unknown. This work is based on a monitoring in six different French cities performed during summer and winter seasons. HULISWS analysis was performed with a selective method of extraction complemented by carbon quantification. UV spectroscopy was also applied for their chemical characterisation. HULISWS carbon represent an important contribution to the organic aerosol mass in summer and winter, as it accounts for 12–22% of Organic Carbon and 34–40% of Water Soluble Organic Carbon. We found strong differences in the optical properties (specific absorbance at 250, 272, 280 nm and E2/E3 ratio) and therefore in the chemical structure between HULISWS from samples of summer- and wintertime. These differences highlight different processes responsible for emissions and formation of HULISWS according to the season, namely biomass burning in winter, and secondary processes in summer. Specific absorbance can also be considered as a rapid and useful indicator of the origin of HULISWS in urban environment.