OH Content Research Articles

Water in Omphacite and Garnet From Pristine Xenolithic Eclogite: T‐X‐fO2 Controls, Retentivity, and Implications for Electrical Conductivity and Deep H2O Recycling

AbstractKimberlite‐borne eclogite xenoliths having Precambrian oceanic crustal protoliths and entrained from ≥100 km depth can retain pristine geochemical features despite extended residence in the cratonic lithospheric mantle, making them valuable archives of deep chemical cycling including that of water. We determined, by Fourier Transform Infrared Spectroscopy, structural OH contents in clinopyroxene and garnet from 15 unmetasomatized eclogite xenoliths. Calculated total c(H2O) is 100–510 wt.ppm for clinopyroxene and below detection (∼2 wt.ppm) to 200 wt.ppm for garnet, while garnet δ18O, determined by Secondary Ion Mass Spectrometry, ranges from +5.0‰ to +7.3‰, (similar to high‐ and low‐temperature seawater‐altered oceanic crust). Estimated electrical conductivity in pristine eclogites increases with temperature (i.e., depth for conductive geotherms), while clinopyroxene‐garnet H2O partition coefficients decrease with increasing temperature and garnet grossular component (i.e., Ca#), similar to other incompatible components. Various considerations suggest the retention of primary H2O in the samples, likely occurring in km‐sized pods of coarse‐grained eclogite. High Al2O3 in clinopyroxene as omphacite component, stabilized during high‐pressure metamorphism, facilitates H2O uptake. Therefore, the high bulk c(H2O) estimated for samples with plagioclase‐rich, deep crustal protoliths (median 290 wt.ppm) may indicate an interaction with fluids expelled at depth from serpentinites. The c(H2O) of ancient and modern subducted bulk oceanic crust (∼220–240 wt.ppm) are similar, suggesting constant mantle ingassing since at least 3 Ga ago. This places constraints on factors, such as mantle temperatures, that determine the efficiency of deep water cycling.

Evolution from basic to advanced structure of fulvic acid and humic acid prepared by food waste

Fulvic acid (FA) and humic acid (HA) are common polyacids in nature. However, the evolutionary process of their basic and advanced structures is still unclear. FA and HA were separated into five molecular weight components to investigate the process of evolution from small to large molecules. The primary structure analysis showed that FA were rich in CN, COOH and OH content, while HA were rich in (CH2)n, NH2 and CC. Moreover, with the molecular weight increasing, the structures could complement each other to maintain the hydrophilic or hydrophobic balance. The 2D-COS spectroscopy demonstrated that during the growth of FA, COOH, NH2 and OH firstly respond. On the other hand, during the growth of HA, NH2 and (CH2)n firstly respond. In addition, advanced structure of FA was affected by intramolecular hydrogen bonds and π − π interaction. HA was affected by hydrophobic interactions due to the abundance of hydrophobic groups, primarily (CH2)n and benzene rings. 3D conformational fitting and particle size characterization confirmed that the interaction forces determine that FA and HA become tightly and loosely molecules respectively. This study is to further explore the geochemical formation and evolution process of FA and HA molecules.

Physicochemical Characterization and Oxidative Potential of Iron-Containing Particles Emitted from Xuanwei Coal Combustion.

Respiratory diseases have been proven to be directly related to air pollutants. Xuanwei, located in South China, has been known to have the highest mortality rate for lung cancer in China because of the air pollutants emitted through local coal combustion. However, the mechanism of lung cancer induced by air pollutants is not clear. Based on the fact that a large number of iron-bearing mineral particles was found in Xuanwei coal combustion particles, the iron-containing particles were hypothesized to play important roles in the pathogenesis of the high incidence rate of lung cancer in this area. In this study, raw coal samples were collected from a coal mine in the Xuanwei area. Size-resolved particles emitted from the raw coal samples were collected using an Anderson high-volume sampler. Mineralogical characterization and an assessment of the oxidative potential of the iron-containing particles were conducted using cutting-edge technologies, and the biological activity of the particles were evaluated via DTT assay. Our data showed that the iron-containing minerals accounted for more than 10% of the measured particles emitted from Xuanwei coal combustion samples. The content analysis of ·OH generated from Xuanwei coal combustion particles showed that ·OH content was dependent on the size of particles in the surrogated lung fluid. The concentration of ·OH increased as the particle size decreased. The DTT assay data further demonstrated that when the mass concentration of dissolved irons increased, the oxidation potential of the particles increased. The highest proportion of divalent iron in the total dissolved iron was found in the submicron particles in low pH solution(pH = 1), which indicated that the oxidative potential induced by submicron particles was stronger than that induced by coarse particles and fine particles. Armed with the above data, the toxicological mechanism of the iron-containing mineral particles can be investigated further.

Lewis acid/base mediated deep eutectic solvents intensify lignocellulose fractionation to facilitate enzymatic hydrolysis and lignin nanosphere preparation

In this work, Lewis acids (FeCl3, AlCl3) and bases (Na2CO3, Na2SO3) were incorporated into a neutral deep eutectic solvent (DES, choline chloride/glycerin) to intensify the lignocellulose fractionation. The efficiency of fractionation in terms of the maximum delignification rate (89.7 %) and well-pleasing cellulose saccharification (100 %) could be achieved by the Lewis acid-mediated DES. An in-depth insight of the evolution of lignin structure revealed that Lewis acid-mediated DES could cleave the β-O-4 linkages efficiently to achieve a high yield lignin fragments. Meanwhile, the lignin fragments with the enhanced amphiphilic properties facilitate the preparation of lignin nanospheres (LNSs) via the self-assembly process. The resultant LNSs extracted by Lewis acid-mediated DES exhibited an excellent thermal stability, and enhanced antibacterial capacity, which were associated with the phenolic OH content. However, the extracted lignin by Lewis base-mediated DES was mainly attributed to the cleavage of lignin-carbohydrate complexes bond, especially the lignin-carbohydrate ester bond, which retained more ether bonds and a relatively complete structure. This study illuminated the different mechanisms of lignin extraction and the structural evolution of lignin from Lewis acid/base-mediated DES, and provided guidance to select suitable fractionation techniques for upgrading the downstream products.

Influence of natural cellulose on hydroxyl radical generation by abiotic oxidation of pyrite under acidic conditions

Natural cellulose is one of the most important substances coexisting on the surface of pyrite. Oxidation of pyrite produces hydroxyl radicals (•OH). In this study, a pyrite-cellulose binary system was constructed with natural cellulose to investigate the effect of cellulose on the mechanism of •OH generation via oxidation of pyrite, and the mechanism for abiotic oxidative •OH production by pyrite under the influence of cellulose was investigated with oxidation and quenching experiments and characterization techniques. It was demonstrated that cellulose was chemisorbed onto the pyrite surface and some of the Fe(II) on the pyrite surface was masked, thus inhibiting the reaction between pyrite and O2 and decreasing the •OH production level from 33.54 to 22.48 μM under oxic conditions. In addition, the cellulose caused SS bond breakage, resulting in defects on the pyrite surface, which oxidized H2O to produce •OH in anoxic conditions. Therefore, under anoxic conditions, cellulose promoted the production of •OH and increased the •OH content from 11.85 to 14.78 μM. In addition to •OH, pyrite oxidation also produced SO42−. The amount of SO42− produced by a single pyrite crystal was less than that produced in the pyrite-cellulose system in all cases, and the amount produced under oxic conditions was approximately 10 times greater than that produced under anoxic conditions. More sulfate production indicated more sulfur intermediates during the reaction, such as S2O32−, which may decompose to produce S0 or Sn2− adsorbed on pyrite and decrease the amount of •OH produced. During the oxidation of pyrite by H2O2, cellulose competed with pyrite to react with H2O2, which inhibited the reaction between pyrite and H2O2 and decreased •OH production. Therefore, natural cellulose influenced the abiotic oxidation of pyrite to produce •OH.

Synergistic enhancement of the catalytic performance of BiOBr: The role of surface hydroxyl groups and amorphous FeOOH

The performance of photocatalysts need to be further improved in sewage treatment. In this study, polyethylene glycol (PEG) and zinc nitrate hexahydrate (Zn(NO3)2•6 H2O) co-modified BiOBr with deposition of amorphous FeOOH (AF/ZPBB) is synthesized via precipitation-immersion method. Amazingly, the adsorption capacity of catalysts for organic pollutants is enhanced through surface hydroxyl (-OH) induced by PEG and Zn2+. Meanwhile, the photocatalytic performance of AF/ZPBB is improved by reducing its energy gap (Eg) and suppressing the recombination of photogenerated carriers owing to the presence of amorphous FeOOH. Specifically, the degradation rates for rhodamine B (RhB) and tetracycline hydrochloride (TCH) are 5.5 times and 4.2 times higher than those of pure BiOBr catalyst, respectively. In addition, AF/ZPBB displays pH stability in the pH range of 2–10. After 5 cycles of reaction, only a slight catalytic performance is reduced. The reason is mainly attributed to the reduction of the -OH content, thus inhibiting the synergistic effect of adsorption and photocatalysis. Finally, •O2- is confirmed to be the main active species using ESR and active species capture tests. This work provides a new design approach for effectively enhancing catalytic performances of inorganic semiconductor photocatalysts.

The impact of redox annealing on intrinsic properties and fluoride adsorption performance of CeO2 nanomaterials

The presence of excess fluoride ions in drinking water has raised widespread concerns, necessitating the development of effective methods for its removal. Cerium dioxide (CeO2) holds promise as a selective adsorbent for fluoride ions, due to its exceptional affinity for fluoride and stability across a wide pH range. However, the impact of intrinsic properties of CeO2 on its adsorption characteristics and mechanisms remains unclear. In this study, we prepared a range of CeO2 materials with diverse intrinsic properties by adjusting the annealing temperature and atmosphere. Through a series of characterization techniques, we discovered a correlation between the content of oxygen vacancies, Ce(III) species, and surface hydroxyl groups (–OH), all of which decreased simultaneously with increasing air annealing temperature. With respect to the adsorption performance, the highest fluoride adsorption capacity of 111.1 mg g−1 was observed in un-CeO2, representing the nanomaterials with the highest oxygen vacancies. This capacity gradually decreased to 29.1 mg g−1 in 800-CeO2. Following fluoride adsorption, the oxygen vacancy density, Ce(III) content, and surface –OH content of all CeO2 materials decreased. When CeO2 materials were annealed in H2 for 1 h, the F− adsorption density increased due to the formation of more oxygen vacancies and surface –OH. Based on our findings, we conclude that oxygen vacancies play a critical role in determining whether fluoride ions can successfully exchange with surface –OH groups and enter the crystal lattice of CeO2, which significantly affects the adsorption performance. The pivotal role of oxygen vacancies, as proposed in this study, provides a valuable direction for future research aimed at enhancing the fluoride adsorption performance of CeO2.

Tailoring near-infrared luminescence with Er3+/Tm3+/Yb3+ tri-doped tellurite glasses for applications in the C, L and U bands

In this work, co-doped and tri-doped systems with Er3+, Tm3+ and Yb3+ were evaluated in tungsten-tellurite glasses to extend the amplification range of current Erbium-Doped Fiber Amplifiers (EDFAs). The conditions of synthesis showed that the use of appropriate atmosphere was efficient to decrease the OH content and enhance the Er3+ emission. Spectroscopic studies on Er3+ and Tm3+ co-doped glasses revealed an emission from 1500 to 2000 nm with the energy transfer between both ions and the luminescence from Er3+: 4I13/2 → 4I15/2 and Tm3+:3F4 → 4H6. The addition of Yb3+ increased around 4 times in the NIR luminescence at 1535 nm. Lifetime measurements showed an increase of energy transfer efficiency (η) from Er3+ to Tm3+ as Tm2O3 content increased. In addition, temperature-dependent luminescence is studied for co-doped and tri-doped systems in the range of −180 to 75 °C. As temperature decreases, the ratio between Er3+ and Tm3+ emissions increases whereas the introduction of Yb3+ considerably enhanced the emission from Er3+ at 1535 nm related to Tm3+. This study demonstrates that the NIR emission of these tellurite glasses, both in intensity and bandwidth, can be considerably tailored by means of the dopant content, synthesis conditions, and temperature.

Improving the adhesion of diamond-like carbon films on glass substrate by chemical etching and oxygen plasma treatment

The weak adhesion of diamond-like carbon (DLC) films on glass has hindered their widespread application. Despite extensive research on interlayers to enhance adhesion, the challenge of poor DLC adhesion on glass surfaces remains unresolved. In this study, a new strategy is proposed to improve DLC adhesion on glass. Initially, the glass was chemically etched to generate continuous and micrometer-sized pits on the surface. Subsequently, oxygen plasma treatment was employed on the etched glass to increase the Si–OH content on the surface. SiO2, SiOC and DLC were then sequentially deposited on the etched glass using magnetron sputtering. The film materials were embedded into the pits, resulting in a wavy 3D morphology. This morphology facilitated the distribution of applied force on the inclined planes of the pits and increased the contact area between the film and the glass surface, thereby improving the chemical bonding between the film and the substrate. The adhesion strength, Vickers hardness and pencil hardness of the films on the glass were 135.37 mN, 751.8 HV and 8H, respectively. These results demonstrate the effectiveness of the proposed approach in addressing the issue of weak DLC adhesion on glass. The findings of this study have potential applications in various fields.

Exploring the Influence of ZnF2 on Zinc-Tellurite Glass: Unveiling Changes in OH Content, Structure, and Optical Properties.

Tellurite glasses have garnered considerable interest as optical host materials due to their advantageous properties, including low processing temperature, high resistance to corrosion and crystallization, and excellent solubility for rare earth ions. However, their applicability in the infrared (IR) region is limited by the absorption of species with distinct vibrations. The incorporation of fluorides has emerged as a promising approach to reduce hydroxyl (OH) absorption during the precursor melting process. In this study, we investigated the influence of ZnF2 on a glass matrix composed of TeO2-ZnO-Na2O, resulting in notable changes in the glass structure and optical properties, with Eu3+ serving as an environmental optical probe. The samples underwent comprehensive structural, thermal, and optical characterization. Structural analyses encompassed 19F and 125Te nuclear magnetic resonance (NMR), with the latter being complemented by mathematical simulations, and these findings were consistent with observations from Raman scattering. The main findings indicate an enhancement in thermal stability, modifications in the Te-O connectivity, and a reduction in emission intensity attributed to the effects of ligand polarizability and symmetry changes around Eu3+. Additionally, the fluorotellurite matrices exhibited a shift in the absorption edge toward higher energies, accompanied by a decrease in mid-IR absorptions, thereby expanding the transparency window. As a result, these glass matrices hold substantial potential for applications across various regions of the electromagnetic spectrum, including optical fiber drawing and the development of solid-state emitting materials.

An exploration of lattice transformation mechanism of muscovite single crystal under EB irradiation at 0–1000 kGy

AbstractElectronic components made by inorganics (e.g., mica) play key roles in the function exertion of instruments working in outer‐layer space, enduring long‐term β‐ray irradiation. Its damage is vital while explored rarely. Herein, pure muscovite crystals were chosen and irradiated by an electron beam (EB) in air with a dose up to 1000 kGy. Then, micro‐geometry morphology variation in Z‐axis and microstructural transformation mechanism were explored by X‐ray diffraction, Fourier transform attenuated total reflection infrared spectrum, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and CA analysis. Main results reveal that muscovite lattice is unstable to EB irradiation. With dose increases to 1000 kGy, interlayer space d of (0 0 2) lattice varied 2% near 0.2 Å. At low‐dose, irradiation lattice expansion readily occurs, whereas at higher dose, it is lattice shrinkage, showing a transformation from expansion to shrinkage. Concurrently, chemical structure varied, H2O amount increased, and metal element valance and surface wettability were reduced, so dehydroxylation occurred exceeding H2O radiolysis and evaporation, and framework cleavage could be severe. Binding energies of metals of 1000 kGy‐irradiated species decreased by 0.2 eV, and CA of 100 kGy‐irradiated species increased by 10°. Intrinsic mechanisms involve framework destruction, H‐atom migration, hydrogen bond formation/destruction, and H2O radiolysis. At low‐dose irradiation, H‐atom migration and hydrogen bond formation/destruction are predominant, inducing lattice expansion; at higher dose, framework cleavage is intensive and crucial, inducing shrinkage. During which, partial H2O occurred radiolysis, reducing valence. Generally, H‐atom migration and interface cleavage played key roles in microgeometry morphology a variation of muscovite crystal under EB irradiation at 0–1000 kGy. To enhance muscovite geometry‐morphology stability under a long‐term β‐ray irradiation condition, OH and hydrogen bond contents should be reduced and interface region should be strengthened (e.g., lessening vacancies or compacting stacking). This conclusion promotes the design of radiation‐resistant silicate material, guiding the manufacturing of electronic component used in aerospace industry significantly.

OH incorporation and retention in eclogite-facies garnets from the Zermatt–Saas area (Switzerland) and their contribution to the deep water cycle

Abstract. The incorporation mechanisms of OH groups in garnet were investigated in a suite of high-pressure rocks from the Zermatt–Saas area (Switzerland) using a combination of Fourier transform infrared spectroscopy (FTIR) and electron probe micro-analysis (EPMA). Investigated garnet specimens include grossular–andradite–uvarovite solid solutions in serpentinite and rodingite and almandine–grossular–pyrope–spessartine solid solutions in eclogite, mafic fels and meta-sediment. All rocks experienced the same peak metamorphic conditions corresponding to a burial depth of ∼ 80 km (∼ 540 ∘C, 2.3 GPa), allowing determination of the OH content in garnet as a function of rock type. The capacity for OH incorporation into garnet strongly depends on its composition. Andradite-rich (400–5000 µg g−1 H2O) and grossular-rich garnet (200–1800 µg g−1 H2O) contain at least 1 order of magnitude more H2O than almandine-rich garnet (< 120 µg g−1 H2O). Microscale analyses using FTIR and EPMA profiles and maps reveal the preservation of OH zoning throughout the metamorphic history of the samples. The OH content correlates strongly with Mn, Ca and Ti zoning and produces distinct absorption bands that are characteristic of multiple nano-scale OH environments. The use of 2D diffusion modelling suggests that H diffusion rates in these rocks is as low as log(D[m2 s−1]) = −24.5 at 540 ∘C. Data were collected for the main garnet-bearing rock types of the Zermatt–Saas area allowing a mass balance model of H2O to be calculated. The result shows that ∼ 3360 kg H2O km−1 (section of oceanic crust) yr−1 could be transported by garnet in the subducting slab beyond 80 km depth and contributed to the deep-Earth water cycle during the Eocene subduction of the Piemonte–Liguria Ocean.

Effect of transport distance on the size distribution, graphitized structure, surface functional groups and oxidation activity of PM from diesel engine: A comparison of waste cooking oil biodiesel and petroleum diesel

In order to provide a theoretical basis for the development of aftertreatment devices, this paper investigated the exhaust particles of petroleum diesel (B0) and waste cooking oil biodiesel (B100) using EEPS, XPS and TGA. The results showed that the particle number distributions of different particle sizes showed a bimodal distribution. With the increase of transport distance, the peak value of the nuclear mode particles decreases and of accumulation mode particles increases. With the increase of transport distance, the O/C ratio of the particles decreased, but the ratios of sp3/sp2, C–OH and CO content increased, i.e., the farther the transport distance was, the higher the degree of disordered graphitization structure was, and the surface oxygen-containing functional groups increase. The oxidation characteristic temperature decreased with the increase of transport distance, and the activation energy of exhaust particles decreased by more than 10%, i.e., the farther the transport distance, the higher the oxidation activity of the particles. Compared with B0, B100 particles have less PN, more disordered graphitized structure, more C–OH and CO content, and higher oxidation activity. The transport distance had similar effects on the size distribution, graphitized structure, surface functional groups and oxidation activity of B0 and B100 particles.

Dark mantles over domes and rilles on the Moon: Evidence for pyroclastic materials

A collection of dark mantles covering volcanic domes and surrounding rilles were examined. Remotely sensed information on FeO and TiO2 content, clinopyroxene (CPX) and olivine (where olivine is an assumed proxy for glass) abundance, band center positions near 1 and 2 μm, and a parameter related to OH and/or H2O content were assessed for these mantling deposits. Based on our examination of these dark mantles associated with domes and rilles we found that all of the examined dark mantles had higher FeO abundances than the surroundings. The Birt E pit of Rima Birt and the mantle over the Manilius-1 dome are higher in glass and lower in CPX than their surroundings and with deeper band depth near 3 μm: all these indicators suggest higher pyroclastic glass abundance. The mantle at Rima Calippus is also nominally glass-rich although its band depth near 3 μm is comparable to nearby mare basalts and thus is not taken to be unusually hydrated. The dark mantles associated with the Yangel-1 and Cauchy-5 domes are higher in CPX, lower in glass, and higher in TiO2 content with low band depth near 3 μm indicating they are glass-poor and nominally rich in ilmenite. The Hyginus crater of Rima Hyginus is distinct from the other studied mantles in that it has higher TiO2 content, lower CPX abundance, higher glass or olivine, and weak 3 μm band depth. Also, the band minimum near 1 μm deos not occur at a longer wavelength than surrounding mare suggesting that in this instance the higher olivine (as a proxy for glass) might actually be due to olivine rather than glass. Thus, in the study of dark mantles associated with domes and rilles each represents deposits and eruptions that need to be characterized on a case-by-case basis rather than as a collective group.

Regulating sludge composting with percarbonate facilitated the methylation and detoxification of arsenic mediated via reactive oxygen species

This study purposed to demonstrate the impact of reactive oxygen species (ROS) on arsenic detoxification mechanism in sludge composting with percarbonate. In this study, sodium percarbonate was used as an additive. Adding sodium percarbonate increased the content of H2O2 and OH, which the experimental group (SPC) was higher than the control group (CK). In addition, it decreased the bioavailability of arsenic by 19.10%. Metagenomic analysis found that Firmicutes and Pseudomonas took an active part in the overall compost as the dominant bacteria of arsenic methylation. ROS positively correlated with arsenic oxidation and methylation genes (arsC, arsM), with the gene copy number of arsC and arsM increasing to 7.74 × 1012, 5.24 × 1012 in SPC. In summary, the passivation of arsenic could be achieved by adding percarbonate, which promoted the methylation of arsenic, reduced the toxicity of arsenic, and provided a new idea for the harmless management of sludge.

Insights on structure and antioxidant properties of lignin extracted from Eucalyptus by deep eutectic solvent/2-methyltetrahydrofuran biphasic system treatment

A deep eutectic solvent (DES, choline chloride/lactic acid)/2-methyltetrahydrofuran (2-MTHF) biphasic system was proposed to deconstruct the recalcitrance of Eucalyptus under different conditions for efficient extraction of lignin (DES-phase lignin (D-L) and organic-phase lignin (O-L)). The recovered lignin had relatively high total yield (61.65–83.69 %), low molecular weight (2400–1440 g/mol), and high purity. Results showed that the D-L had relatively higher aliphatic OH contents but lower phenolic OH contents than that of corresponding O-L, and the antioxidant activity of the O-L was higher than that of the corresponding D-L. Additionally, the total phenolic OH contents of the recovered lignin (1.92–2.96 mmol/g) were much higher than that of double enzymatic lignin (DEL, 1.29 mmol/g) because of the breakage of β-O-4′ linkages of the lignin in DES phase. Overall, the lignin fractions recovered from the DES and 2-MTHF phase has obvious difference, which is beneficial to the diversified utilization of lignin.

Reaction heat effect and change characteristics of key groups in coal-oxygen intrinsic reaction path.

The intrinsic reaction of coal with oxygen in the process of low-temperature oxidation is the main reaction path leading to self-heating and spontaneous combustion of coal. Most of the existing studies regard the coal oxidation as an overall reaction, ignoring the multi-path characteristics of coal low-temperature oxidation, and it is difficult to accurately explore the intrinsic reaction characteristics between coal with oxygen. Therefore, the low-temperature oxidation process of coal was studied by using a C80 microcalorimeter and in situ FTIR technology from the macro and micro levels. The "profile subtraction method" was used to study the coal-oxygen intrinsic reaction process, and the reaction heat effect and the change characteristics of key functional groups in the process were analyzed. Furthermore, the gray correlation analysis method was used to study the relevant characteristic parameters in the reaction process and grasp the essential structure-activity relationship. The experimental results show that, compared with the overall reaction process in air atmosphere, the change in the heat release of the coal-oxygen intrinsic reaction path has changed to different degrees, and the change in the slow oxidation stage is the most significant (the heat absorption decreases by 70.1-90.9%). In addition, the characteristic temperature points show different degrees of advance, of which the initial exothermic temperature point is the largest (about 21-46 °C), which directly leads to a significant shortening of the slow oxidation stage (30.1-47.4%). The changes of functional groups in the intrinsic reaction path are more regular. With the increase of temperature, the oxygen-containing functional groups -C=O and the aliphatic hydrocarbon functional groups -CH2- and -CH3 showed a fluctuating trend of increasing and decreasing, respectively. The oxidation heat-contributing functional groups of coal are mainly related to the degree of metamorphism and the functional group reaction characteristics during the reaction. With the deepening of coalification degree, the main heat-contributing functional groups as a whole showed the change rule of oxygen-containing functional groups → aliphatic hydrocarbon functional groups → aromatic hydrocarbon functional groups. In addition, the change of -OH content in the three coal samples has a high correlation with the change of the total heat release of coal.

Controls on metal fertility of dioritic intrusions in the Laiwu district, North China Craton: Insights from whole-rock geochemistry and mineral compositions

Several large high-grade iron skarn deposits in the Laiwu district of Shandong Province (North China Craton) are developed along the contact zone between the Early Cretaceous Kuangshan diorite pluton and Middle Ordovician dolomitic limestone. In sharp contrast, no iron skarn mineralization has been recognized in association with other contemporaneous dioritic intrusions (Jiaoyu, Jinniushan, Tietonggou) in this district. The reason for this contrast remains elusive. Here we present a comparative study of the ore-related Kuangshan pluton and its barren equivalents using whole-rock and mineral (zircon, apatite) geochemistry combined with existing Sr-Nd isotope data to provide new insights into the critical controls on iron skarn mineralization and shed light on future mineral exploration. Geochemical and Sr-Nd isotope data suggest that both the ore-related and barren intrusions were derived from a common enriched lithospheric mantle source following variable degrees of fractional crystallization and crustal assimilation. Modeling based on whole-rock Sr-Nd isotopes implies that the magmas responsible for the Kuangshan and Jinniushan diorite plutons assimilated significant quantities of the Ordovician evaporite-bearing carbonates. Both the fertile and barren diorites show high whole-rock Sr/Y ratios, high zircon Eu/Eu* and Eu/Eu*/Y ratios, and low zircon Dy/Yb ratios. These data, combined with high magmatic water contents (4.4−8.0 wt%) calculated from amphibole compositions, indicate that those four plutons crystallized from hydrous magmas. High whole-rock Fe2O3/FeO, and high ΔFMQ values (mostly >1; fayalite-magnetite-quartz oxygen buffers) estimated from zircon, apatite, and amphibole suggest that the magmas from which the diorite intrusions crystallized were all oxidized. Using available partitioning coefficients for Cl between apatite and magma, the parental melts of the Kuangshan and Jinniushan diorite are estimated to have had higher Cl contents (0.15−0.77 wt%) than the Jiaoyu and Tietonggou diorites (0.06−0.34 wt%). Two types of apatite from the intrusions studied are recognized based on their paragenetic relations: Type 1 apatite (Ap1) is an early-formed phase enclosed in euhedral amphibole, plagioclase, and biotite, whereas type 2 (Ap2) is a late-formed variety hosted in, or intergrown with, anhedral K-feldspar (± anhedral amphibole ± subhedral to anhedral quartz). In the fertile Kuangshan diorite, Cl and OH contents of apatite decrease, but Sr contents increase from Ap1 to Ap2. However, those parameters show reverse trends or remain constant from Ap1 to Ap2 in barren diorites. Such distinctive apatite geochemical signatures are best interpreted as reflecting more efficient fluid exsolution from the parental magma of the Kuangshan diorite than from the barren intrusions. This view is supported by the presence of abundant fluid inclusions in apatite and quartz exclusively from the mineralized intrusion, indicating its crystallization from volatile oversaturated melts. The results presented here indicate that elevated magma Cl contents and efficient separation of magmatic hydrothermal fluid from cooling magmas have been the critical factors controlling iron skarn mineralization in the Laiwu district. Mass balance constraints on Cl budget indicate that a minimum of 44−60 km3 of magma was required to form the Fe deposits associated with the Kuangshan pluton. Our preliminary results suggest that decreasing OH and Cl contents from early to late apatite in intermediate rocks can be used as an indicator for efficient fluid exsolution and consequently metal fertility of those rocks.

Interbreed differences in the cholesterol profile in cattle in Western Siberia

The authors studied the leading indicators of the cholesterol profile of high-density lipoproteins (HDL-C), low-density lipoproteins (LDL-C) and total cholesterol (TC) in Black-and-White, Red Steppe and Holstein breeds of the second or third lactation, bred in large livestock farms—complexes on the territory of Western Siberia. Metabolism and concentration of lipid complexes of cholesterol status play a cardinal role in the homeostasis of cellular metabolic processes. The critical role of serum lipoproteins in cholesterol metabolism is well recognised, as is their role as predictors of cardiovascular disease. At the same time, the atherogenic effect of LRN-C is associated with the transfer of fatty acids, which act as energy substrates for ATP synthesis. Anti-atherogenic properties characterise HDL-C and have an antioxidant and anti-inflammatory effect. The concentration of HDL-C - was determined by the precipitation method of phosphotungstic acid with magnesium chloride; the level of LDL-C - by the enzymatic colourimetric direct method, total cholesterol - by the process of enzymatic hydrolysis and oxidation of CHOD-PAP using reagent kits “HDL-Cholesterol-Novo”, “LDLCholesterol-Novo-A”, “Cholesterol-Novo” (“Vector-Best, Russia. The content of OH and LDL-C in the blood serum of cows at the age of the second or third lactation bred in Western Siberia is higher than the generally accepted standard values, which reflects a different degree of adaptation to climatic conditions. Ranked series of breeds (p < 0.05) according to LDL-C: black-and-white → Holstein → red steppe, medians were 4.91; 2.77 and 2.24 mmol/l, respectively. Differences between the indicators of HDL-C and LDL-C in Black-and-White, Red Steppe and Holstein cows were established, which indicates the genetic determination of the level of lipoproteins in the blood serum. The strength of the influence of the cow breed factor on the level of HDL-C in blood serum was 29%, LDL-C - 17%.

Experimental Study of New Antioxidant to Inhibit Spontaneous Combustion of Coal

ABSTRACT Free radicals and metal ions are key factors causing coal spontaneous combustion. In order to effectively suppress coal spontaneous combustion, experiments were conducted using luteolin as an inhibitor, luteolin is abbreviated as LUT. The influence of different concentrations of LUT on the spontaneous combustion heat characteristics of coal was tested using a C600 high-precision microcalorimeter, and the inhibition mechanism was inferred by FTIR. The experimental results show that LUT is an effective coal oxygen inhibitor, under the same action conditions, different concentrations of LUT can absorb heat to different degrees, delay the initial exothermic temperature of coal, prolong the heat absorption phase of coal. Compared with raw coal, 6 wt% LUT absorbs the most heat, the starting exothermic temperature is delayed by 46°C, and the activation energy is increased by 47.89 kJ/mol, the functional group -OH content decreased by 43.4%, -CH3 decreased by 32.1%, -CH2-decreased by 37.76%. Based on this, the mechanism of inhibition is inferred, LUT not only removes free radicals (ROO•) during the chain initiation stage and captures free radicals (•OH) in the reaction chain but also chelates metal ions to inhibit the catalytic effect of metal ions during the free radical reaction, which can play a dual role in preventing free radical generation and interrupting the free radical chain reaction. The results of the study can provide a novel, environmentally friendly and effective way to prevent the spontaneous combustion of coal.