Degradation Of Organic Components Research Articles

The Effects of the Addition of Secondary Phyllosilicate Minerals on the Decomposition Process and Products of Maize Straw in Black Soil

The interaction between secondary phyllosilicate minerals and straw is crucial for preserving soil organic carbon (SOC) and fertility. However, the specific mechanism through which these minerals affect straw decomposition and its products in northeast China’s black soil remains unclear. In this study, montmorillonite, illite, and vermiculite were mixed with quartz sand and maize straw, inoculated with microbes, and incubated to analyze the effects of different secondary phyllosilicate minerals on the degradation of organic components in maize straw and the formation of soil humus. The results showed that montmorillonite significantly facilitated the decomposition of maize straw hemicellulose and lignin, which decreased by 95.85% and 76.38%, respectively. Conversely, vermiculite decelerated hemicellulose and lignin degradation. Regarding soil organic acids, lactic acid and malic acid were predominant, with the highest content being found after the montmorillonite treatment. Montmorillonite was the most effective in enhancing extractable humic-like substances, which increased by 71.68%. Montmorillonite increased the content of G0 (water dispersion group), G1 (sodium ion dispersion group), and G2 (sodium grinding dispersion group) complexes. The addition of secondary phyllosilicate minerals increased the organic carbon (OC) content in the G0, G1, and G2 samples, with montmorillonite demonstrating the most pronounced effect. Secondary phyllosilicate minerals increased the abundance of fungi, particularly Ascomycota, with the highest abundance being found after the montmorillonite treatment. In conclusion, our results indicated that montmorillonite facilitated the decomposition of lignocellulose in maize straw, enhanced the accumulation of humus, and promoted the formation of organic–mineral complexes. These findings provide valuable insights into the interaction between secondary phyllosilicate minerals and maize straw and have important implications for improving the quality of black soil in northeast China.

Unraveling the intricate fouling behaviors of landfill leachate components during membrane distillation concentration toward zero liquid discharge

Membrane distillation (MD) holds promise for cost-effectively concentrating wastewater toward zero liquid discharge (ZLD), while membrane fouling problems still hinder its practical application, especially for high-strength wastewater containing complex constituents. This study investigated the effects of different foulant components in actual landfill leachate (LFL) on MD deep concentration performances. The fouling behaviors of LFL components were revealed by comprehensively characterizing and analyzing the physicochemical properties of the fouling layers and membrane-foulant interactions. Results illustrated that suspended solids (SS) and macromolecular organics (MO) played significant yet distinct roles in fouling layer formation. SS (>0.45 μm, ∼24 % TOC) possessed strong adhesion energies with membrane surfaces and constructed the main skeleton of the fouling layer at the preliminary concentration stage; while MO (>20 kDa, 0.36 % TOC) deposition resulted in a densely packed fouling layer, influencing the salt crystallization potential and interfering with water and ammonia transport. In contrast, the low-molecular organics with the highest content (<20 kDa, ∼75 % TOC) were mainly electron-donor monopolar substances weakly adsorbed on the nonpolar membrane surface. Removing SS and MO from LFL notably prevented fouling layer formation and maintained high membrane efficacies (water flux decline mitigated from ∼50 % to ∼15 % and ammonia rejection increased from 71 % to 88 %), even as water recovery increased to 95 %. The findings of this work imply conventional anti-fouling strategies (e.g., complete removal or degradation of organic components) may have gone beyond what is necessary, and will inspire the development of simpler and greener methods to maintain membrane efficacy during high-strength wastewater treatment toward ZLD.

Enhanced organic degradation and microbial community cooperation by inoculating Bacillus licheniformis in low temperature composting

Microbial activity and interaction are the important driving factors in the start-up phase of food waste composting at low temperature. The aim of this study was to explore the effect of inoculating Bacillus licheniformis on the degradation of organic components and the potential microbe-driven mechanism from the aspects of organic matter degradation, enzyme activity, microbial community interaction, and microbial metabolic function. The results showed that after inoculating B. licheniformis, temperature increased to 47.8°C on day 2, and the degradation of readily degraded carbohydrates (RDC) increased by 31.2%, and the bioheat production increased by 16.5%. There was an obvious enhancement of extracellular enzymes activities after inoculation, especially amylase activity, which increased by 7.68 times on day 4. The inoculated B. licheniformis colonized in composting as key genus in the start-up phase. Modular network analysis and Mantel test indicated that inoculation drove the cooperation between microbial network modules who were responsible for various organic components (RDC, lipid, protein, and lignocellulose) degradation in the start-up phase. Metabolic function prediction suggested that carbohydrate metabolisms including starch and sucrose metabolism, glycolysis / gluconeogenesis, pyruvate metabolism, etc., were improved by increasing the abundance of related functional genes after inoculation. In conclusion, inoculating B. licheniformis accelerated organic degradation by driving the cooperation between microbial network modules and enhancing microbial metabolism in the start-up phase of composting.

Synergy of cold plasma and sulfate radicals in the treatment of dye-contaminated wastewater; mechanistic study of the degradation mechanism using DFT

Organic dyes including azo and xanthene dyes are used widely, and ultimately discharged into wastewaters. Owing to the drawbacks of conventional water treatment, different advanced oxidation processes (AOPs) have been combined with nonthermal atmospheric pressure plasma (NTAPP) as sustainable alternatives for reclaiming dye-polluted wastewater. Herein, the synergy of NTAPP and sulfate radicals were utilized for treating real colored wastewater. Individual and combined systems of NTAPP and UV-C activated sulfate and hydroxyl radicals were evaluated based on their removal efficiencies for two model dyes: Rhodamine B (Rh.B) and Congo red (CR). The combined system of NTAPP and UV-C activated persulfate (PSUVP) was the most efficient with >80 % degradation of both dyes in 10 min and showed synergy factors of 2.55 and 5.71 for Rh.B and CR degradation, respectively. Moreover, PSUVP was highly efficient in TOC removal from Rh.B (90 %) and CR (67 %) solutions. The determining oxidants in Rh.B and CR degradation were the singlet oxygen and sulfate radical, respectively. The DFT analysis revealed that higher number of acidic hydrogens were available in CR compared to Rh.B and this might be one reason for observing the influential role of SO4∙- in CR degradation. Although the background constituents had negligible effects on Rh.B degradation, the degradation efficiency of the PSUVP system decreased by 30 % in real wastewater containing 50 ppm CR. The treatment of real colored wastewater using PSUVP resulted in 94 % TOC removal. Despite the toxicity of the PSUVP (toxicity unit ≥1), which can be mitigated by diluting the treated wastewater before discharge, this system exhibited high efficiency in decolorization and degradation of organic components. Thus, the proposed system has promising potential for the treatment of industrial effluents with high TOC.

Physical-mechanical properties and thermogravimetric analysis of fired clay brick incorporating palm kernel shell for alternative raw materials

This article explores the potential of incorporating palm kernel shells (PKS) from palm oil mill waste as a clay replacement for fired clay bricks. PKS, an abundant byproduct of palm oil extraction, have high cellulose content and high calorific value, making them an ideal option for clay replacement in brick making. For this purpose, clay soil was replaced with different percentages of PKS (0, 1, 5 and 10%) and subjected to a firing temperature of 1050 °C (heating rate of 1 °C/min). The physical–mechanical properties such as shape, size, colour, dry density, water absorption, thermal conductivity, porosity and compressive strength, as well as microstructural and morphological properties (XRD, SEM-EDX and digital image) and thermal analysis data (TGA-DTA) were evaluated to determine the effects of replacing PKS in fired clay bricks. The results showed that the incorporation of PKS increased firing shrinkage and porosity and decreased dry density, compressive strength, and thermal conductivity. However, incorporating more than 5% PKS resulted in lower mechanical properties (24.6 to 11.0 MPa) and higher water absorption (3 to 12%) due to increased firing shrinkage and porosity (0.3 to 0.9% and 13 to 20%, respectively). The bricks also exhibited lower density (1799 to 1645 kg/m3) and improved thermal properties (0.54 to 0.36 W/m.K) due to the development of porosity during the firing process. While the degradation of organic components was a concern, it was determined that all organic components were completely degraded below 650 °C and the bricks matured at 950 °C. The study concluded that the use of PKS as a partial replacement for clay in brick manufacture is a viable solution for waste management.

Effects of Regular Water Replenishment on Enzyme Activities and Fungal Metabolic Function of Sheep Manure Composting on the Qinghai-Tibet Plateau.

The dry climate characteristics of the Qinghai–Tibet Plateau will seriously affect microbial metabolism during composting. In this study, we aimed to investigate the effects of regular water supplementation on the fungal and enzymatic activities of sheep manure composting in the Qinghai–Tibet Plateau. The experiment set up the treatments of water replenishment once every 7 days(T2) and 3.5 days (T3) days, and no water supplementation was used as the control (T1). The results showed that regular water supplementation increased the activities of various enzymes during composting, and the activities of protease, cellulase, peroxidase and polyphenol oxidase in T3 were higher than those in T2. Regular water supplementation increased the relative abundance of Remersonia and Mycothermus, which were significantly positively correlated with the germination index, and degradation of organic components. Regular water supplementation could enrich fungi carbohydrate, protein, and nucleotide metabolisms, and T3 had a better effect. A redundancy analysis showed that environmental factors could significantly affect the fungal community; among them, moisture content (76.9%, p = 0.002) was the greatest contributor. In conclusion, regular water supplementation can improve the key enzyme activities and fungal metabolic function of sheep manure composting, and water replenishment once every 3.5 days had the best effect.

Influences of changing inorganic nitrogen concentration on accumulation and degradation of organic components in indigenous microalgae cultivated with secondary effluent

ABSTRACT Climatic changes due to emission of greenhouse gases are a global concern. These emissions occur by combustion of fossil fuels whose drought is near in which case renewable energy is the only alternative. Microalgae are promising sources of sustainable bioenergy production, and utilisation of wastewater as cultures is recommended for economical production cost. In this study, indigenous microalgae, which had adaptability for wastewater samples, were cultivated with a municipal secondary effluent, and influences of changes in inorganic nitrogen (IN) concentration, specifically IN increase, on temporal accumulation and degradation of organic components in indigenous microalgae were investigated. Indigenous microalgae accumulated total lipids and carbohydrates against reduced IN, and increase in superoxide dismutase suggested that the accumulation was possibly induced by generating reactive oxygen species. Continued cultivation of indigenous microalgae under the IN exhausted condition should be avoided because of the resulting total carbohydrate degradation. IN replenishment when IN was decreased but still existed in the culture and that when IN was exhausted in the culture triggered sharp degradation of the total carbohydrate, which possibly utilised to accumulate crude protein and/or chlorophyll a for continuous growth or regrowth. The total carbohydrate was accumulated and recovered after the degradation; meanwhile, two or three days were required for the recovery of the total carbohydrate. In addition, the IN replenishment also resulted in total lipid degradation. Therefore, to produce indigenous microalgae with high and stable total carbohydrate and lipid content, it was critical to prevent IN increase in the culture.

Thermal behavior of N-Methylaniline modified phenolic friction composites

This article discusses observations on thermal stability, decomposition properties and degradation of organic components of friction composite materials fabricated by powder metallurgy techniques. N-Methylaniline modified phenolic resin used as a binder material in the preparation of composite materials. Thermogravimetry method was used to study the thermal properties of the samples. The experiments were performed on a TGA Q50 (TA Instrument) in an oxygen atmosphere. In order to better assess the thermal characteristics of the composites, the analyses were carried out by separating thermographs into three parts according to the degradation mechanism. The obtained results helped to assess the thermal stability of the friction materials. The degradation of phenolic resin was observed in the temperature range of 312–362°C. It was found that barite and copper-graphite particles improve the thermal characteristics of the samples.

Anaerobic fermentation of hydrothermal liquefaction wastewater of dewatered sewage sludge for volatile fatty acids production with focuses on the degradation of organic components and microbial community compositions.

Hydrothermal conversion (HTC) is a promising technology for the treatment of dewatered sewage sludge to produce bio-fuels including bio-oil and hydrochar. At the same time, a huge amount of wastewater (HTCWW) was produced. The present study investigated the organic compositions of HTCWW obtained at different HTC temperatures (170-320°C) and volatile fatty acids (VFAs) yields through anaerobic fermentation. Results showed that the highest VFAs yield of 0.59 gCODVFA/gCOD was obtained from HTCWW obtained at 170°C (HTCWW 170). Higher amount of easily biodegradable organics including proteins and carbohydrates were present in HTCWW 170°C, which resulted in the highest VFAs yields. With the increase of HTC temperature, recalcitrant organic compounds were produced as revealed by 3D-EEM and GC-MS analysis, which resulted in lower VFAs yields. Furthermore, microbial analysis showed that different compositions in the HTCWW led to the enrichment of different microbial communities, which affected the VFAs yields.

Changes in Physical, Chemical, and Microbiological Properties During the Two-Stage Composting of Green Waste due to the Addition of β-cyclodextrin

This research determined whether addition of β-cyclodextrin (β-CD; 0, 0.15, or 0.25%) improved the two-stage composting of green waste (GW). The following parameters were measured during composting or in the final product: moisture content; volume; biochemical and chemical oxygen demand; humic substances; C/Nsolid and C/Nsoluble; microbial numbers (culturable bacteria, actinomycetes, and fungi); enzyme activities (pectinase and xylanase); microbial biomass carbon and nitrogen; degradation of organic components; contents of phosphorus (available and total), potassium, sodium, calcium, and magnesium; and toxicity to germinating seeds. The two-stage composting of GW was optimal with the addition of 0.15% β-CD. A mature and stable compost was obtained in only 28 days with the optimized two-stage composting rather than in the 90–270 days typically required for traditional composting.

Effect of a high strength chemical industry wastewater on microbial community dynamics and mesophilic methane generation

A high strength chemical industry wastewater was assessed for its impact on anaerobic microbial community dynamics and consequently mesophilic methane generation. Cumulative methane production was 251 mL/g total chemical oxygen demand removed at standard temperature and pressure at the end of 30 days experimental period with a highest recorded methane percentage of 80.6% of total biogas volume. Volatile fatty acids (VFAs) analysis revealed that acetic acid was the major intermediate VFAs produced with propionic acid accumulating over the experimental period. Quantitative analysis of microbial communities in the test and control groups with quantitative real time polymerase chain reaction highlighted that in the test group, Eubacteria (96.3%) was dominant in comparison with methanogens (3.7%). The latter were dominated by Methanomicrobiales and Methanobacteriales while Methanosarcinaceae in test groups increased over the experimental period, reaching a maximum on day 30. Denaturing gradient gel electrophoresis profile was performed, targeting the 16S rRNA gene of Eubacteria and Archaea, with the DNA samples extracted at 3 different time points from the test groups. A phylogenetic tree was constructed for the sequences using the neighborhood joining method. The analysis revealed that the presence of organisms resembling Syntrophomonadaceae could have contributed to increased production of acetic and propionic acid intermediates while decrease of organisms resembling Pelotomaculum sp. could have most likely contributed to accumulation of propionic acid. This study suggested that the degradation of organic components within the high strength industrial wastewater is closely linked with the activity of certain niche microbial communities within eubacteria and methanogens.

The revenge of time: fungal deterioration of cultural heritage with particular reference to books, paper and parchment

Hyphomycetous fungi - so called 'mould'- are the most important agents of biodeterioration in museums, museums' storage rooms, in libraries, collections and restoration studios. Fungi are able to live at low water activities, they are perfectly adapted to indoor environments and thrive in microclimatic niches caused by condensation, lack of ventilation or water retention by hygroscopic materials. Fungi spoil valuable pieces of art aesthetically, mechanically, chemically and by degradation of organic components. Historical material made of paper and oil paintings with high amounts of organic binders are especially susceptible to fungal deterioration. In order to prevent fungal contamination or to treat already contaminated objects an integrated approach including climate control, material-specific cleaning and application of carefully selected biocides is necessary.

Geochemistry and mineralogy of coal in the recently explored Zhundong large coal field in the Junggar basin, Xinjiang province, China

Abstract The Zhundong coalfield is a very large coal deposit, currently under exploration, and promises to be an important coal mining resource in Western China. The coal reserves amount to 164 Gt. At Xiheishan and Wucaiwan, the coal-bearing units are the Badaowan (Lower Jurassic) and, especially, the Xishanyao formations (Middle Jurassic). These contain from one to 31 coal seams (one to 10 workable coals reaching the rank of high volatile A bituminous) with an accumulated workable coal thickness of 20–87 m. These recently explored coal reserves are of a high quality and are characterized by low ash, aluminum, iron, sulfur, and trace element contents. The minerals present in this coal are mainly quartz, kaolinite, siderite, and pyrite. The trace element contents in both Xiheishan and Wucaiwan coals are much lower when compared with the usual concentration ranges present in Chinese coals, with the exception of Ba and Sr. Thus, Ba contents in Xiheishan coal are higher than Swaine's worldwide concentration range. A large number of elements have mainly aluminosilicate affinity, and occur in clay and other detrital coal minerals. Ca and Mn have mainly carbonate affinity; Fe and S have mainly sulphide affinity in Wuchaiwan coal. In Xiheishan, Fe, Mn and Mg have mainly carbonate affinity (siderite), and probably, B, Co, Ni and S have an organic affinity. Thus, the Zhundong coalfield contains coal with a very high quality and very low levels of impurities. The very low ash yields, S, Fe, and trace element contents may be attributed to the sedimentological setting, with intensive peat bog aggradation in a very shallow lake environment with a low detrital supply. The very low sulfur content, the relatively high Ba-sulfate (barite) content and the high siderite occurrence in Xiheishan coal (in contrast to the pyrite occurrence in Wucaiwan coal) may be attributed to the rapid aggradation of peat with the consequent oxidation and leaching of minerals, elements, and degradation of organic components. Under this scenario, sulfate is trapped by the continuous precipitation and accumulation of barium sulfate (very low soluble).

Restrictions on fluorine depth profiling for exposure age dating in archaeological bones

Archaeological fragments of bone and teeth that are exposed to a humid environment take up fluorine from the surrounding soil. The fluorine ion replaces the hydroxyl group in the mineral phase of the bone, forming chemically more stable fluorapatite. In cortical parts of the long bone diaphysis a fluorine concentration profile can be observed, which decreases from the outer surface and the marrow cavity towards the inner parts of the bone matrix. Geological time spans are needed for this process to reach equilibrium and for the distribution to become uniform. As the shape of the profile, which can be described by a diffusion model, contains information on the exposure duration of the fossil object, several attempts to use fluorine profiling as a dating method have been undertaken. The distribution of fluorine in an archaeological sample however is strongly influenced by environmentally induced processes of bone diagenesis, i.e. alteration in the structure and composition of the mineral phase and degradation of organic components that may make the time information indistinct. The primary chemical composition of bones can thus be obscured by diagenesis within tens, hundreds or thousands of years. This depends more on the diagenetic environment than on the geological age. To observe the impact of environmental influence on the profile shape, samples from several burial sites featuring various soil conditions have been analyzed for their fluorine distribution and preservation state. This paper provides an overview on the restrictions that have to be considered when attempts are undertaken to relate a fluorine diffusion pattern to the archaeological age of a bone specimen.

A Mathematical Model for Rotating Biological Contactors

A mathematical model for aerobic and anoxic degradation of organic components as well as nitrification in RBC systems is developed and verified against experimental experience after primary, secondary and tertiary treatment. The model considers biomass distribution within the biofilm as well as along a reactor chain. The simulation program is not yet ready for practical application but may well prove to become a design tool in the future.

Enzyme histochemical studies of induced heterotopic cartilage and bone formation in guinea pigs with special reference to acid phosphatase.

Heterotopic bone and cartilage formation was studied in a bone induction model in abdominal muscles of guinea pigs using the demineralized allogenic dentin as inductive material. The light microscopic study showed high activity of acid phosphatase (AcP) and leucine aminopeptidase (LAP) in young matrix-producing cells. The highest activity was seen in cells surrounded by unmineralized matrix. In the surrounding matrix there was strong staining of AcP, especially in matrix with high glycosaminoglycan content. Electron microscopic studies of AcP in sections from unfixed frozen tissue showed intracellular activity mainly located in lysosomes. Extracellular AcP activity was found in matrix vesicles in the newly formed hard tissue. It was most pronounced in areas of cartilaginous differentiation. By means of energy dispersive X-ray microanalysis in a scanning transmission electron microscope, the deposits were confirmed to contain led precipitates. With the exception of some lysosomal staining, prefixation with formaldehyde prevented demonstration of the enzyme activity. Both AcP and LAP may be involved in degradation of organic components of the matrix which enable the matrix to mineralize.

Thermal decomposition characteristics of humus horizons from culbin forest

Differential thermal analysis in an oxygen atmosphere and pyrolysis in vacuo combined with mass spectrometry have been used to follow the transformations occurring during the humification of vegetation. Two processes are indicated, one, apparently enhanced by liming consisting of oxidative degradation and the other corresponding to degradation of organic components with high thermal dissociation energies. At the base of some profiles the humus has characteristics close to those of translocated humus in freely drained soils.