Chemical composition and distribution of the components of valley peat from Amur oblast

The chemical composition of sedge peat from the Egor’evskoe deposit as lowland peat from Amur oblast was characterized. The elemental composition of organic matter and mineral macro- and microcomponents was studied, and the distribution of bitumens, their fractions, and humic acids in the depth of occurrence was revealed. It was found that peat genesis processes occur over the entire vertical profile, and the most converted organic matter is formed at a depth of to 90 cm. The individual composition of alkane fractions consists of C₁₃–C₃₆ normal structure homologues with a carbon preference index somewhat higher than unity; the presence of pristane, phytane, and farnezane was detected. In the fractions of fatty acids, predominantly even compounds from C₁₀ to C₃₀ were identified with special distribution features at the separate stages of peat formation. The analysis of the individual composition of n-alkanes and fatty acids made it possible to supplement botanical characteristics with information on the contribution of macrophytes, algal material, and microorganisms to the formation of the organic matter of peat.     

雨养沼泽泥炭腐植酸的性质和结构

腐植酸类物质是土壤、泥炭和自然水体中有机物的主要成分,其来源不同,结构和性质也不同。本研究阐述了雨养沼泽泥炭腐植酸的性质,评估了泥炭剖面内腐植酸的均质性,并研究了泥炭腐殖化程度对腐植酸性能的影响。结果表明,以不同来源的苔藓为主的雨养沼泽植物对泥炭腐植酸结构的影响较大。泥炭腐植酸的成岩作用程度介于活有机体和煤炭之间,当碳水化合物、氨基酸等被破坏后,耐分解的芳烃和多环芳烃结构出现,泥炭腐植酸的结构趋于形成。然而,与土壤、水体和其他腐植酸相比,泥炭腐植酸的芳香性较低。相对而言,雨养沼泽泥炭腐植酸处于活有机体向成岩转化过程的初始阶段。羧基和酚羟基含量的变化取决于提取腐植酸的泥炭年龄和分解程度,羧酸酸度随泥炭深度和腐殖化程度增加而增大。     

Physicochemical principles of hydrophobization of mineral binders by additives produced from peat raw material

The results of theoretical and experimental studies aimed at developing a method for hydrophobization of mineral binders and building materials based on them by additives extracted from the organic matter of peat are presented. The processes occurring in heat treatment of peat are studied by analyzing the conversion of groups of chemical substances contained in peat. An increase in the concentration of hydrophobic compounds in thermal destruction of peat raw material is substantiated. The hydrophobizing effect of the additives is based on the formation of water-repellent adsorption films of bitumen compounds on cement particles. A working hypothesis of the mechanism of their formation is advanced.     

Study on the acid hydrolysis of Peat: 1. extraction of carbohydrates

Peat and its derived products such as peat extracts or hydrolysates offer a variety of possibilities as raw materials for the development of chemical and biochemical processes. Acid hydrolysis of peat yields soluble carbohydrates which can be utilised as fermentation media. In this work, Sphagnum peat moss was hydrolysed under various conditions of H₂SO₄ concentration, retention time, temperature, peat concentration, peat particle size distribution and original moisture content in the peat. The results suggest that mild conditions of hydrolysis, which will minimise possible negative effects on other nutrients available in peat, are adequate for the release of the carbohydrates present in peat. It was found that peat particle size distribution and original moisture content as well as peat concentration will also affect the yield of carbohydrates obtained.     

Thermal analysis in the evaluation of compost stability: a comparison with humification parameters

Characterization of organic matter of six composts from agroindustrial wastes was carried out by both chemical analysis and thermal analysis in order to assess their level of stability. Degree of humification (DH%) and index of humification (HI) were calculated after extraction, fractionation and analysis of the organic carbon from composts. Differential Scanning Calorimetry (DSC) and thermogravimetry (TG) were simultaneously performed in oxidizing conditions on whole ground composts. Thermoanalitical data resulted to be useful in integrating quantitative information coming from chemical analysis of humified fraction of compost organic matter. Particularly, DSC curves allow to distinguish between well and poor stabilized composts, and information deriving from weight losses, registered by TG curves, permits to individuate a thermoanalytical parameter (R1) that resulted to be well correlated to humification parameters DH% and HI.     

Identification of peat and leonardite using humification parameters and Isoelectric focusing (IEF): A first approach

Several samples of peat and leonardite (organic fossil material of vegetable origin) and of humic extracts from peat and leonardite were characterized using some humification parameters and isoelectric focusing (IEF). The HA/TOC and the humification rate (HR) show values lower than 60% for peat and higher than 70% for leonardite samples. These two parameters are useful to distinguish peat from leonardite, but unable to identify the organic materials in the humic extracts. Peat an leonardite samples and their humic extracts were characterized using IEF and evaluating the quantitative distribution of the bands of the profile. The group of bands in the range from pH 4.8 to 5.5 (region C) is characteristics in all samples. In particular, the relative area is less than 55% for peat and humic extracts from peat and higher than 60% for leonardite and humic extracts from leonadite.     

Effect of soil environment on the photo‐degradation of polyethylene films

Outdoor weathering field trials performed with oxo‐degradable polyethylene (PE) thin films were conducted across temperate, grassland, and subtropical sites around Australia. It was found that a site factor, that was apparently independent of total solar dose and temperature, significantly impacted the rate and extent of photo‐oxidation. Controlled laboratory‐based accelerated aging trials of both PE film with no prodegradant and oxo‐degradable PE films (containing iron stearate) revealed that the rate and extent of PE photo‐oxidation did not correlate with temperature under the film or UV exposure, but was soil dependent. Under accelerated photo‐oxidative conditions, the time to reach embrittlement for a PE film aged over the soil from the temperate site (OM 8.4) was half (24.5 days) the time taken when aged over air (48 days). Further investigation revealed that humic acids and fulvic acids within soil organic matter may contribute to an increased rate of PE photo‐oxidation, possibly through the formation of volatile reactive oxygen species that may form under photo‐oxidative conditions. The presence of water also had a significant impact on the rate of photo‐oxidation. Overall, the impact of soil on PE photo‐oxidation was found to be complex and likely dependent at least in part on soil components that varied between different soil types, consequently influencing their photo‐chemistry. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42558.     

Thermal dissolution of combustible shale from the Dmitrievskoe deposit in benzene under supercritical conditions

The results of the thermal dissolution of combustible shale in benzene under supercritical conditions in a flow system are reported. It was found that the conversion of the organic matter of combustible shale into liquid products increased by a factor of 2.2 as the solvent pressure was increased from 5 to 15 MPa; in this case, the fraction of high-molecular-weight products in them increased by a factor of 2.     

Material losses in liquefaction of raw peat with carbon monoxide

The loss of organic material into the aqueous and gas phases in the liquefaction of raw peat with ≈ 90 wt% moisture content has been studied. The raw material was treated with CO at an initial pressure of 5.5–8.3 MPa and a temperature of 300–350 °C in the presence of K₂CO₃. The yield of water, water-soluble and gas products depended on the operating conditions and the chosen input material. In the liquefaction of peat with 31 wt% oxygen content the loss of material into the aqueous and gas phases decreased with increases in the initial CO pressure and the reaction temperature. The loss of organic material from peat with a high oxygen content (≈ 40 wt%) was significant. This loss of organic material is a result of thermal decomposition and hydrolysis of the organic matter of the peat and elimination of low molecular weight gases and water-soluble compounds with high oxygen and low energy contents. The selective transfer of highly oxygenated components from the peat resulted in the formation of liquid and solid residual materials with low oxygen and high energy contents. Most of the energy content of the peat becomes concentrated in the liquid and solid products (toluene- or acetone-solubles and -insolubles). The loss of organic material from the peat into the aqueous and gas phases is not accompanied by significant energy losses from the raw material.     

Composition changes of soil humus after massive application of urban waste compost: a comparison between FT-IR spectroscopy and humification parameters

A laboratory trial and a six-year field experiment were carried out to evaluate the changes in the composition of humic substances in a soil amended for six years with urban waste compost (UWC), and to compare the results obtained by FT-IR spectroscopy with empirical humification parameters. The fulvic acid FT-IR spectra showed that amended soils contain a higher concentration of carboxylic and aliphatic groups compared to unamended soil (UNAS). The six-year amended soil (SYAS) also showed a higher content of polysaccharides on FT-IR spectra of both humic and fulvic acids. The polysaccharide increase in the six-year amended soil is attributable to the humification process since polysaccharides were not present in a high quantity in the UWC or laboratory amended soil (LAAS). The humification index and the degree of humification values indicate that the urban waste compost and soils studied can be classified in decreasing order of humification as follows: UNAS > SYAS > LAAS > UWC. This behaviour is the consequence of an increasing presence of the non humified fraction in NaOH extracted organic matter. The carboxylic and aliphatic groups content from FT-IR spectra confirmed this behaviour, thus indicating the validity of the humification parameters used to evaluate the status of the organic matter from refuse and soil.     

Changes in the composition of the bituminous components of valley peat under stimulated microbial action

The stimulated microbial oxidation of valley peat by aboriginal microflora was experimentally studied for evaluating the participation of microflora in the conversion of organic matter in present-day swamp deposits. The esters of n-carboxylic acids, triphenyl phosphates, C₁₄–C₃₁ n-alkanes, squalene, methyldehydroabietate, steroids, and pentacyclic terpenoids with the predominance of unsaturated structures mainly with the alcohol groups were identified in the composition of the bituminous components of microflora. It was found that the absolute concentrations of all of the identified groups of organic compounds in peat considerably decreased as a result of biodegradation. The relative concentrations of high-molecularweight (C₂₇–C₃₄) homologues and C₁₆–C₂₀ homologues predominant in bacteria in the composition of peat n-alkanes increased. Steroids and pentacyclic triterpenoids were enriched in unsaturated structures and compounds with the alcohol groups. Aldehydes disappeared from the composition of acyclic compounds. The fractions of palmitic acid derivatives in methyl ethers and isoprenoid structures in alkanones sharply increased.     

Geochemistry of two peats suitable for medical uses and their behaviour during leaching

The compositional characteristics of two peats, from Austria and Italy, have been studied. The Massaciuccoli peat shows a high quantity of trace elements (Br, Cd, Mo, Se, U, As and Sb) with respect to the average shale, whereas the Neydharting peat contains more Br, Se and U. Since the therapeutic properties of peats are broad and interesting, the mobility of trace elements (As, Cd, Hg, Pb, Sb, Se, Te and Tl) used for pelotherapy, during water leaching and after Na exchange, have been checked. The data concerning the leaching procedure indicate that the analysed peats are rather stable materials under laboratory conditions. Although the concentration of some toxic elements (As, Se, Cd and Hg) in bulk peats are of the same order of magnitude as in muds used in pelotherapy, the release after similar leaching is lesser. The higher release from muds could be explained by the high exchange capacity of smectite minerals. These minerals are characterised by low cation selectivity because the chemical interactions between smectite and sorbed species is mainly ionic. On the other hand, the cation–organic matter interactions can establish a higher degree of covalent bonds, that are more stable during the interactions developed with leaching. An additional possibility can be considered taking into account the genetic conditions of peat formation. In the upper part, the acidic and oxidising conditions cause the depletion of mobile elements. This process can be seen as a natural cleaning, which occurs under relatively strong conditions compared to the use during medical treatments.     

The Adsorption of Pollutants by Peat,Lignite and Activated Chars

The ability of peat, lignite and activated chars made from peat and lignite to adsorb dyes and metals from wastewater and NO₂ from air was investigated. Equilibrium isotherms were determined to assess the maximum adsorption capacity of the adsorbents for the pollutants. Kinetic studies for the adsorption of dyes and metal ions onto the adsorbents were undertaken in agitated batch adsorbers. Mass transport models were tested to predict the concentration decay curves in batch adsorbers. The models tested were single resistance models based on the assumption of a single external mass transfer coefficient and two resistance models which included an internal diffusion coefficient and an external mass transfer coefficient. The surface phenomena which influence the extent and the rate of uptake have been studied. The equilibrium capacity data conform to Langmuir plots. A previously proposed model was used to evaluate the external single resistance mass transfer model and was successfully applied to predict the adsorption of metal ions in single component systems under batch conditions. It has been shown that the assumption of negligible intraparticle diffusion is valid and that external film diffusion is the rate limiting step in describing the adsorption processes at high sorbent loadings. The same type of result is not observed for the adsorption of coloured organic matter onto peat where the sorption processes cannot be successfully modelled by use of a single resistance model and a two resistance model incorporating internal diffusion is required. The surface phenomena which influence the extent and the rate of uptake of NO₂ have been studied. The type of chars produced and the activation processes affect the adsorption. As activation increases, micropore volume and surface area increase and the maximum capacity of the adsorbent increases. Surface area alone is not the only parameter which affects equilibrium uptake. © 1997 SCI.     

Transformation of polyconjugation systems as a factor of enhancing the sorption activity of peat upon its modification with phosphoric acid and organic acids

The treatment of peat with the solutions of phosphoric, citric, and oxalic acids in concentrations of 10⁻⁴ and 10⁻² mol/l at solid phase to liquid ratios of 1: 2.5 and 1: 5 increased the absorption of ammonia by 6.4–39.7%. The absorption of ammonia was higher than the concentration of doping ion-exchange groups by a factor of 5–2000. With the use of EPR and IR spectroscopy, it was found that this phenomenon was caused by the transformation of polyconjugation systems as a result of the interaction of acids with the organic matrix of peat by a macrocoordination mechanism, which also improved the technological characteristics of the resulting sorbents. The absence of the destruction of organic matter with the use of low concentrations of weak acids makes it possible to use these sorbents after operation in gas-purifying equipment as organic fertilizers enriched in nitrogen.     

Peat hydrogenolysis using H2/CO mixtures: Micropetrological and chemical studies of original material and reaction residues

The transformation of crude peat (peat in its natural aqueous medium) has been studied under hydrogenolysis conditions using CO and H₂ mixtures as reducing agent. Batch autoclave experiments were conducted with a moderately humified peat at reaction temperatures up to 400°C.Micropetrological and chemical studies on untreated and treated peat as well as on THF extracted residues show that the different organic components present in peat undergo changes very similar to those observed during coal liquefaction. Liptinitic components are rapidly converted and do not appear in the unconverted residues above 275°C. The huminitic components regularly increase their reflectivity and appear to have been coalified to the stage of subbituminous coal A, from that point on being the major contributors to the newly formed vitroplast. The latter is observed for the first time following the hydrogenolysis treatment at 300°C. Beyond this temperature the vitroplast undergoes severe alterations becoming a bitumen-like material.In the presence of anthracene oil as organic carrier solvent, the hydrogenolysis reactions using CO and H₂ result in the formation of mesophase at temperatures as low as 380°C. Coke-like structures can thus be formed from peat.     

Biomethanation: Its future development and the influence of the physiology of methanogenesis

Bioconversion of organic matter into methane by anaerobic bacteria is a process better understood each day. The technology of biomethanation takes advantage of this in a number of ways, three of them being examined in this paper. First, when biomethanation is conducted under continuous, completely mixed conditions without active biomass recycle, a bottleneck may arise from the limited number of methanogenic bacteria present in the digestion mixed liquor. As the specific methane production rate was shown to be also limited, the resulting overall methane production must remain low. ‘Second generation’ methane digesters are being designed so as to trap the methanogenic bacteria within the digester, a fact which was demonstrated by the accumulation in the methane digestion mixed liquor of coenzyme F₄₂₀. Second, when the feedstock for biomethanation consists of insoluble organic matter, the preliminary solubilisation of this insoluble matter is often rate-limiting. It was shown that the inverse of conversion varies linearily with the inverse of mean residence time, which allowed the calculation of ‘ultimate’ conversion. Application of this technique to the individual components of a complex feedstock, determined independently, allowed us to identify problems of rate limitation and of bacterial competency. Two-step methane digestion systems should help to overcome this second bottleneck. Third, monitoring of the biomethanation process needs major improvements. Even simple analytical methods such as dry organic matter or chemical oxygen demand determinations suffer major drawbacks and may lead to erroneous estimated efficiencies. A graph is proposed which attempts to correlate heats of combustion, mean oxidation stages and specific chemical oxygen demands with efficiencies with the aim of detecting anomalous values.     

Photovoltaic solar electrochemical oxidation (PSEO) for treatment of lignosulfonate wastewater

BACKGROUND: Under the current global energy scenario, the need for self‐sustainable processes is encouraged. The photovoltaic solar powered electrochemical oxidation (PSEO) process has been developed to remove the organic matter from a lignosulfonate wastewater. RESULTS: An electrochemical reactor using boron‐doped diamond electrodes, in a batch configuration, is directly supplied with current from a set of photovoltaic solar modules. Experimental results show that the process can oxidize about 90% of the total organic carbon (TOC) of the organic matter in the wastewater under the described operating conditions. CONCLUSION: The technical suitability of the PSEO process has been demonstrated. A model to relate solar irradiance and electrical current was applied and used in a kinetic expression which depends on solar irradiance to describe the removal of TOC. Copyright © 2010 Society of Chemical Industry     

What Are We Trying to Separate?

Abstract

Heterogeneity both invites and permits separation of components. Coal is heterogeneous at a number of levels. At the simplest level it is a mixture of organic and inorganic phases. The textures and therefore the liberation characteristics of the inorganic components are a response to the sedimentary and metamorphic processes associated with coal formation. Mineral matter occurrence ranges from coarse interbeds and veins to micron sized inclusions and can be selectively associated with specific organic entities. The organic matter in coal is itself heterogeneous at two major levels. At the simplest level, three major groups of macerals are developed (largely as a result of processes in the peat stage). Each group of macerals is both chemically and physically distinctive from the other group and yet is also gradational into the neighboring group. At the finest level of heterogeneity, each maceral is itself a complex mixture of organic compounds. The organic material also contains organically bound elements, such as sulfur and alkalis, which are generally difficult to separate, but can be highly significant in coal utilization. A further level of complexity is introduced by the variation in the chemical and physical properties of all of the macerals (and to a lesser extent the minerals) as a response to rank change.

Separation processes have to take into account the levels of heterogeneity, and to be effective on a specific coal must be appropriate to the variations in properties shown by that coal for each type of heterogeneity. Full characterization of coals at the research, and pilot plant stages is essential if results are to applied to commercial scale processes.     

Thermal solution of Kashpir shale in pressurized benzene under supercritical conditions

The results of the thermal solution of oil shale in benzene in a flow unit under supercritical conditions are reported. It was found that the conversion of shale organic matter into liquid products increased by a factor of 2.5 with an increase in the solvent pressure from 5 to 15 MPa.     

Oxidation Of Iron And Manganese By Ozone

The oxidation of iron and manganese by ozone was studied in the laboratory. Model waters both with and without organic matter were used. Results showed iron to be very rapidly oxidized to an insoluble form in the absence of organic matter. However, in the presence of organic matter the iron was protected from oxidation by ozone and precipitation. The degree to which this occurred depended on the nature of the organic matter and the chemical environment at the time of mixing the iron stock and the dissolved organic matter.

Experiments with manganese allowed the determination of second order rate constants for the reaction of ozone with manganese at various pH values. The oxidation of manganese in the presence of organic matter occurred in competition with oxidation of the organic matter. As a result, high ozone doses were required to achieve the same degree of removal of manganese. An increase in bicarbonate alkalinity from 50 mg/L to 200 mg/L did not result in an acceleration of the manganese oxidation in the absence of organic matter. However, in the presence of organic matter, higher levels of bicarbonate created conditions that resulted in more complete oxidation of the manganese following total consumption of the dosed ozone.