Separation Of Humic Substances Research Articles

Characters and Metallogenetic Significance of Organic Matter in Coal from the Daying Sandstone-Hosted Uranium Deposit in the Northern Ordos Basin, China

Coal is usually found in many sandstone-hosted uranium deposits in western China. However, it remains unclear whether coal organic matter is related to the mineralization of uranium in sandstone. In this study, the organic matter of coal containing lenticular carbon plant strips and carbon clastics was analyzed in different alteration zones in the Daying sandstone-hosted uranium deposit located in the northern Ordos Basin. According to geological and geochemical characters, Daying sandstone can be classified into three alteration zones: the oxidation zone, the transition zone, and the reduction zone. The results are as follows. Firstly, the maceral organic matter of the coal at Daying is mostly vitrinite, indicating the characters of humic coal. The maturity of the organic matter is low, which is in the transitional evolution stage of immature lignite or lignite-long-flame coal. Secondly, the kerogen is mainly type III (humic type), which can be easily transformed into humic acid with a strong adsorption capacity for uranium. Thirdly, the vitrinite reflectance (Ro) of the coal organic matter in the transition zone is higher than that of the other alteration zones. Meanwhile, there are bright white bands in the microscopic components of the organic matter of the coal in the transition zone (mineralized zone) and a certain composition of the sapropelite has strong fluorescence. All three aforementioned phenomena are related to the radioactivity of uranium, and each of them possesses the potential for application in mineral exploration. Fourthly, the extraction and separation of humic substances indicates that humic acid plays a key role in organic matter-related uranium mineralization. In the transition zone, uranium can co-precipitate as a humate, and the transition zone’s organic carbon content increases. Therefore, the organic matter in coal contributes to sandstone-hosted uranium mineralization, providing a further guide to prospecting methodologies.

Waste-free processing of lowland peat for production of liquid organomineral fertilizers

The Tyumen Region holds extensive resources of peat, which should be considered as a raw material for the production of organic and organomineral fertilizers. The purpose of this research is the development of a waste-free technology for the production of organomineral fertilizers based on humic substances of lowland peat. The tests of three grades of organomineral fertilizer were carried out in accordance with the State Test Methodology, and soil properties were determined in accordance with the relevant state standards (GOSTs). The humic acid extraction method developed at the General Chemistry Department of the Northern Trans-Ural State Agricultural University produces two types of waste in a large volume: a liquid sediment mixture after separation of humic substances from peat and a supernatant solution after precipitation of humic acids. At present, a non-waste method for obtaining organic-mineral fertilizers from lowland peat has been patented. From a liquid sedimentary mixture of peat and humic substances, a peat–humic fertilizer is prepared for application to the soil. This fertilizer increases crop productivity and humus content, and reduces soil acidity. From the supernatant solution with fulvic acids, a huminomineral fertilizer is prepared for foliar feeding of plants. After centrifugation, a humic product is prepared from the gel of precipitated humic acids for pre-sowing, foliar and root feeding of plants. The products were tested on spring wheat, spring rapeseed, onion and apple trees. All products increased the yield and quality of products. The profitability of the production of three grades of organomineral (one product of each stage of production) fertilizer in comparison with the production technology of only one biostimulant is increased by 2.3 times. Currently, the procedure for their state registration is underway.

Karakteristike kvalitativnog sastava organske materije zemljišta - problemi i rešenja

The components of soil organic matter (SOM) such as lipids (waxes, fats, and resins), pigments (oxyanthraquinones and related substances, tetrapyrrole compounds and carotenoids), kerogen, glomalins, and hydrophobins are briefly described in the paper. In the traditional assessment of the qualitative composition of SOM, all of the above substances, as well as the products of hydrolytic destruction of detritus and partially decomposed plant material, pass into the alkaline solution. The resulting mixture, containing both specific and individual organic compounds, is usually subdivided into fulvic acids, hematomelanic and humic acids. It is proposed to revise the methodology for extracting various components of SOM. The new method should be based on the affinity of the SOM components for certain organic solvents and should allow the separation of humic substances and melanin from glomalin and hydrophobins.

Landfill Leachates Treatment by /UV, /, Modified Fenton, and Modified Photo-Fenton Methods

Advanced oxidation processes (AOPs) such as H2O2/UV, O3/H2O2, modified Fenton, and modified photo-Fenton processes have been investigated in terms of the treatment of landfill leachate with ratio of BOD5/COD in the range of 0.22 to 0.24. The modification of Fenton and photo-Fenton processes consisted in the inclusion of precipitation and separation of humic substances at pH 3. Due to the precipitation, the value of COD decreased by 39% and BOD5by 7.1%. The modification of the processes allowed us to improve the efficiency and to decrease the doses of reagents necessary to continue the process. Modified photo-Fenton process proved to be the most effective (92.7% COD removal) of all processes investigated. Additionally, modified-Fenton process was much more effective than the other two processes when compared up to 120 min, while after longer times it gave the least satisfactory results. After 30 min of modified-Fenton process BOD5/COD ratio increased to 0.43. The parameter referred to as “efficiency of oxidants” was used to estimate the efficiency of all the processes—its value varied from 178 to 239%. Various substances including phthalates, hydrocarbons, silanes, and siloxanes were identified in raw and treated leachate.

Some theoretical and practical aspects in the separation of humic substances by combined liquid chromatography methods

Permanent need to understand nature, structure and properties of humic substances influences also separation methods that are in a wide scope used for fractionation, characterization and analysis of humic substances (HS). At the first glance techniques based on size-exclusion phenomena are the most useful and utilized for relating elution data to the molecular mass distribution of HS, however, with some limitations and exceptions, respectively, in the structural investigation of HS. The second most abundant separation mechanism is reversed-phase based on weak hydrophobic interactions beneficially combined with the step gradients inducing distinct features in rather featureless analytical signal of HS. Relatively great effort is invested to the developments of immobilized-metal affinity chromatography mimicking chelate-forming properties of HS as ligands in the environment. Surprisingly, relatively less attention is given to the ion-ion interactions based ion-exchange chromatography of HS. Chromatographic separation methods play also an important role in the examination of interactions of HS with pesticides. They allow us to determine binding constants and the other data necessary to predict the mobility of chemical pollutants in the environment. HS is frequently adversely acting in analytical procedures as interfering substance, so more detailed information is desired on manifestation of its numerous properties in analytical procedures. The article topic is covered by the review emphasizing advances in the field done in the period of last 10 years from 2000 till 2010.

Influence of organic matter in the prediction of iodine migration in natural environment

ABSTRACTHalogenation of phenolic moieties is one of the most important reactions between humic substances (HS) and iodine or chlorine. These reactions were studied in order to assess the importance of these interactions with reduced (I−) and oxidised (I2) form of iodine. I−was fixed by the addition of Na2S2O3. After separation of HS and I−by ultrafiltration, no significant uptake was evidenced in the time framework of this study. The consumption of I2(aq) by HS was followed by the decay of I−3absorbance (351 nm). It comes out that (i) when I−is fixed by Na2S2O3, no interaction with HS could be quantified; (ii) I2(aq) does react with HS but the kinetics cannot be linearalised. This study confirms the significance of iodine-organic matter interactions as a governing process for iodine migration in surface environment. More studies are on going to develop predictive models of iodination kinetics.

Analysis of membrane fouling in the treatment of water solutions containing humic acids and mineral salts

The separation of humic substances from aqueous solution by ultrafiltration was investigated with flat Intersep Nadir membranes. Special consideration was given to the decrease of membrane permeability in the course of the ultrafiltration process. The decrease of membrane permeability was related to the increase of pH and calcium ion concentration in the solution. Transport properties were found to be strongly dependent on the hydrophilicity of the membranes. The membrane made of regenerated cellulose, the most hydrophilic of the membranes tested, displayed the highest permeability with respect to both water and humic substance containing solutions, and the lowest proneness to fouling by organic colloids. Analysis of the relationship between the properties of the solution and the course of the separation process revealed that the rise of pH from 4.6 to 7.0 reduced membrane fouling. The presence of mineral salts in the solution deteriorated the separation and transport properties of the membranes and intensified the fouling process.

HPLC fractionation and structural dynamics of humic acids

Different soil extracted humic acids as well as a commercial humic acid sodium salt were fractionated by HPLC. An almost complete recovery could be achieved for the dissolved material. All humic samples show a typical chromatogram of at least five fractions. The separation of humic substances is influenced by an altered hydrophobicity due to changes in the tertiary structure. Three fractions were further investigated by Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and by HPLC/HPLC separation. DRIFT spectroscopy provided data on the primary structure, whereas HPLC/HPLC results gave insight into the secondary and tertiary structure and their changes.

Separation of Humic Substances by Porous Ion-Exchange Membranes from Sulfonated Polysulfone

Abstract Ultrafiltration involving sulfonated polysulfone membranes provides high efficiency for humic matter removal from water. The increase in ion-exchange capacity of the polymer matrix from 0.24 to 0.96 mmol SO3H groups per 1 g of dry membrane increases the membrane pore diameter and its hydrophilicity, and thus the permeate flux from 0.05 to 3.69 m3/m2·d. In order to decrease the manufacturing cost, membranes from polysulfone and sulfonated polysulfone blends were investigated. It was shown that a one-to-one blend resulted in a membrane having similar antifouling properties to pure sulfonated polysulfone. Both membranes reject humic matter in the 91–98% range and show a flux decline of 5–30% as a result of surface fouling.

Separation of humic substances by pH gradient desorption from a hydrophobic resin

Separation of humic substances by pH gradient desorption from a hydrophobic resin

Separation of humic substances by gel filtration on Sephadex

Separation of humic substances by gel filtration on Sephadex