Oxygen Compounds Research Articles

Pemanfaatan Vitamin C Alami sebagai Antioksidan pada Tubuh Manusia

Vitamin C is an organic substance needed by the human body in small amounts, to maintain metabolic functions and also acts as an antioxidant for the human body, to ward off free radicals. The design of this research is a literature review of research articles collected by means of computer searches through google schoolar and repository. The search step is to enter the keyword Natural Vitamin C Antioxidant, Dosage and source of intake of vitamin C. Vitamin C or L-ascorbic acid is a water-soluble antioxidant (Aqueous Antioxidant). Vitamin C is part of the body's defense system against reactive oxygen compounds in plasma and cells. Vitamin C deficiency and excess will have an effect on our health. Lemons contain about 85 milligrams of vitamin C, guava has a high vitamin C content of 86 mg/100g, 1 pineapple or a plate of longan fruit (about 100 grams) contains about 80 milligrams of vitamin C, and in a bowl of spinach (about 30 grams) contains 8.5 mg of vitamin C.

Increasing the bio-aromatics yield in the biomass pyrolysis oils by the integration of torrefaction deoxygenation pretreatment and catalytic fast pyrolysis with a dual catalyst system

The integration of Torrefaction Deoxygenation Pretreatment (TDP) and Catalytic Fast Pyrolysis (CFP) with dual catalysts was employed to improve the yield of bio-aromatics (BTX) derived from Miscanthus. Results showed that the TDP could effectively remove the oxygen content up to 38.16% at 280 °C. This resulted in a remarkable reduction of undesired oxygenate compounds in the pyrolysis oil. With ZSM-5 catalyst, the dominant components in pyrolysis oil became aromatic hydrocarbons (up to 66.29%) instead of oxygenates. The selectivity of bio-BTX increased with the increase of torrefaction temperature up to 56.63%. For the pyrolysis process, the highest yield (37.54%) and selectivity (56.63%) of bio-BTX were obtained at 600 °C. Compared with ZSM-5, the addition of CaO and MoO3 promoted bio-BTX yield due to the enhanced deoxygenation and olefins aromatization. The integrated TDP and CFP with ZSM-5 and MoO3 significantly improved the selectivity of bio-BTX, reaching the highest selectivity of 70.69% and a yield of 51.07%. Combining these two processes can enhance bio-aromatics yields from biomass, thus considerably improving the quality and value of the liquid product.

Nanoparticle Shape Influence over Poly(lactic acid) Barrier Properties by Molecular Dynamics Simulations.

Climate change is leading us to search for new materials that allow a more sustainable environmental situation in the long term. Poly(lactic acid) (PLA) has been proposed as a substitute for traditional plastics due to its high biodegradability. Various components have been added to improve their mechanical, thermal, and barrier properties. The modification of the PLA barrier properties by introducing nanoparticles with different shapes is an important aspect to control the molecular diffusion of oxygen and other gas compounds. In this work, we have described changes in oxygen diffusion by introducing nanoparticles of different shapes through molecular dynamics simulations. Our model illustrates that the existence of curved surfaces and the deposition of PLA around them by short chains generate small holes where oxygen accumulates, forming clusters and reducing their mobility. From the several considered shapes, the sphere is the most suitable structure to improve the barrier properties of the PLA.

Untargeted Metabolomics Reveals Multiple Phytometabolites in the Agricultural Waste Materials and Medicinal Materials of Codonopsis pilosula

Codonopsis pilosula has been used in traditional Chinese medicine for hundreds of years, where it has been used to treat anaemia, fatigue, a weak spleen, and stomach problems, among other ailments. The roots of C. pilosula are considered medicinal, while the aerial parts are always directly discarded after harvest in autumn or winter. Some studies have shown that the stems and leaves of C. pilosula also contain a variety of active metabolites, including saponins, flavonoids, terpenoids, and polysaccharides. To efficiently utilise resources, waste products from C. pilosula leaves and stems were analysed by untargeted metabolomics and chemometrics. A total of 1508 metabolites were detected and annotated, of which 463 were identified as differentially expressed metabolites (DEMs). These DEMs were grouped into classes, such as carboxylic acids and derivatives, steroids, organic oxygen compounds, fatty acyls, prenol lipids, and flavonoids. Metabolic profiling of C. pilosula tissues showed that the contents of polyacetylenes, polyenes, flavonoids, some alkaloids, steroids, terpenoids, and organic acids were higher in stems and leaves, whereas the contents of the main lignans and some alkaloids were more enriched in roots. Moreover, C. pilosula stems and leaves also contained a lobetyolin, syringin and atractylenolide III, which were detected by LC-MS/MS and HPLC-UV. The extracts of C. pilosula aerial parts also showed stronger antioxidant properties than roots. C. pilosula stems and leaves were rich in active ingredients and might have great value for development and utilisation.

Metabolomics analysis reveals the physiological mechanism underlying growth restriction in maize roots under continuous negative pressure and stable water supply

Metabolomics analysis was used to elucidate the mechanism underlying response of the maize root system to continuous negative pressure and stable water supply. Results showed a significant reduction in continuous negative pressure and stable water supply (NPI) relative to intermittent positive pressure water supply (DI), maize root dry matter accumulation and root shoot ratio in NPI was 20.22%, 34.15% and lower than DI, respectively, yield was 44.10% higher than DI, and superoxide anion, malonic dialdehyde, osmotic adjustment substance content, and antioxidant enzyme activity was reduced. Next, we applied liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, and nuclear magnetic resonance to perform non-targeted metabolomics analysis with the aim of elucidating the physiological basis of root redundant growth restriction. Results revealed presence of 33 different metabolites in NPI, belonging to different categories, including organic acids and their derivatives, nucleosides, nucleotides and their corresponding analogues, lipids and lipid-like molecules, as well as organic oxygen compounds. Moreover, all these were enriched in 44 metabolic pathways, relative to DI. Notably, metabolic pathways, biosynthesis of secondary metabolites, starch and sucrose metabolism, plant hormones biosynthesis, and biosynthesis of plant secondary metabolites might restrict maize roots growth. In NPI was, Trehalose, 2’-deoxyadenosine, isoleucine and ajmaline were 0.34-, 0.05-, 0.004- and 0.17-fold lower than DI, whereas glutamic acid, glutamine and zeatin were 4.62,4.26,4.06 times higher than DI. This might inhibit root redundant growth. In summary, continuous negative pressure and stable water supply inhibited maize root redundant growth restriction by suppressing sugar metabolism and protein synthesis via genetic information transmission.

The mathematical fractional modeling of TiO_2 nanopowder synthesis by sol–gel method at low temperature

Titanium dioxide is a compound of oxygen and titanium with the formula TiO2 present in nature and manufactured on an industrial scale. It is used in several fields and applications such as cosmetics, paint, food, photocatalyst, electrodes in lithium batteries, dye solar cells (DSSC), biosensors, etc., given its importance and its various fields of application, there are several methods of synthesis of TiO2 such as the sol–gel method widely used to obtain nanoparticles. In our study, on the one hand we synthesized titanium dioxide nanopowders crystallized in the anatase phase at a crystal size of 49.25 nm with success using titanium tetraisopropoxide (TTIP) as precursor by the sol–gel method. The powders obtained were analyzed by X-ray diffraction (XRD) with CuKα radiation (λ=0.15406 nm) and Fourier transform infrared spectroscopy (FTIR) in the wave number range 4000−400 cm−1, and on the other hand we present a mathematical model for the prediction of the TiO2 concentration as a function of time and the concentration of reactants by using the fractional order derivative more precise than the whole order derivative, we study the existence and the uniqueness of the solutions. In addition, we determine the points of equilibrium. Numerical simulations and their graphical representations are made to visualize the efficiency of this model.

A Comprehensive Study on the Synthesis and Characterization of TiO2 Nanoparticles Using Aloe vera Plant Extract and Their Photocatalytic Activity against MB Dye

This paper investigates the use of A. vera extract as a natural capping agent for TiO2 nanoparticles as well as a reducing agent for TiO2 nanoparticles. XRD, ultraviolet diffuse reflectance (UV-DRS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDXA) were used to characterize the material. In their X-ray diffraction patterns, the titanium dioxide nanoparticles were found to have a high degree of crystallinity, indicating that they were synthesized. Infrared (FT-IR) spectra were used to determine the chemical composition of the plant extract. The DRS spectra in the UV-visible range reveal a high absorption peak at 356 nm, which indicates the existence of TiO2 nanoparticles in the sample. Shape of nanoparticles was revealed by SEM and TEM morphological investigations, which revealed their irregular and somewhat spherical nature. Only titanium and oxygen compounds were found in the EDX spectrum, indicating that they were present. This demonstrates that the NPs that were produced are devoid of contaminants. Using the produced nanoparticles as catalyst, we presented a photocatalytic degradation method for the dye methylene blue in this paper. The findings showed that 94 percent of the damage occurred within 120 minutes of being exposed to UV radiation.

Recent development of Silver-catalyzed Oxo- and Aza cyclization

This article addresses new developments in silver-catalyzed cyclization processes, resulting in the formation of carbocyclic or heterocyclic rings. Some essential techniques in organic chemistry include silver-catalyzed reactions. In addition, silver catalysts have been emerged as a novel catalysis in the last two decades. In these sequences, preparations of oxygen and nitrogen-containing heterocyclic compounds emerge as the most important development of new methodology. Silver catalysts exhibit significant reactivity in mild conditions in contrast to other transition metals such as copper, lead, zinc, ruthenium, gallium, indium, and niobium. These developments have lots of scientific attention due to their potential to synthesise of heterocyclic compounds in medicinal and agrochemical use. This current literature review summarises several silver-catalyzed oxo and aza-cyclization processes using readily available starting materials.

Influence of waste plastic on pyrolysis of low-lipid microalgae: A study on thermokinetics, behaviors, evolved gas characteristics, and products distribution

In this study, co-pyrolysis of low-lipid Nannochloropsis sp. (NS) and waste polystyrene (PS) was deeply investigated using TG-MS-FTIR and Fixed bed reactor to characterize their thermal behaviors, kinetics, evolved gases, and products distribution. The (D)TG investigation of the co-pyrolysis process revealed two distinct stages of thermal decomposition: the first stage (150–420 °C) was mostly caused by NS decomposition, whereas the second stage (420–550 °C) was attributed to NS-PS decomposition. The difference between experimental and theoretical mass loss (ΔW) was lower than zero when the proportion of NS was 75% and 65%. In addition, the average activation energy of the blends containing 75% and 65% of NS was less than sole NS. Thus, based on thermal behaviors and activation energies, the blends with an NS content of 75% and 65% exhibited the strongest synergistic effect. The results of TG-MS, TG-FTIR, and GC-MS analyses revealed that the co-pyrolysis considerably boosted the production of hydrocarbons, notably aromatic hydrocarbons, while concurrently restricting the production of nitrogenous and oxygenous compounds. This study will contribute to a better understanding of the utilization of low-lipid microalgae.

Radiation-induced oral mucositis — radiation-induced oral mucositis: pathogenesis, risk factors, clinical manifestations, prevention, and treatment

This study presents the modern concepts of pathogenesis, risk factors, etiology, clinical manifestations, prevention, and treatment of oropharyngeal mucositis, one of the main complications of radiation therapy for head and neck region cancer. The leading role in the mechanisms of disease development belongs to rapidly dividing cells of the basal layer of the oropharyngeal mucous membrane. This damage is due to both direct (excitation and ionization) and indirect (accumulation of active oxygen and nitrogen compounds, activation of transcription factors, hyperfunction of pro-inflammatory cytokines, etc.) action of ionizing radiation on the most important biological molecules and supramolecular structures (polynucleotides, nucleoproteins, phospholipids, etc.). The main risk factors for mucositis include the localization and size of the tumor, the amount of radiation dose to the oral region, and individual body characteristics (young age, pernicious habits, metal structures of dentures, a history of periodontal disease, etc.). The disease severity is described from mild (erythema and moderate pain that does not require analgesia) to severe (ulceration, hemorrhage, necrosis, and other symptoms) to establishment necessary prescription of effective means of pathogenetic and symptomatic therapy. The main means and methods of prevention of radiation-induced mucositis include the following: non-steroidal anti-inflammatory drug benzydamine, means of protection against oxidative stress glutamine, and drugs with a complex stimulating effect on wound healing processes. Drug therapy for mucositis involves the use of benzydamine; the tricyclic antidepressant doxepin; and a gel consisting of polyvinylpyrrolidone (Belclaiz), mucolytic acetylcysteine. When non-narcotic analgesics are ineffective, low doses of opiates (fentanyl, morphine, and methadone) are used in oral, transdermal, or parenteral dosage forms, as well as low-intensity laser therapy. The most important components of the etiopathogenetic therapy of the disease include antiviral drugs (acyclovir and valacyclovir) and fungicides (clotrimazole, fluconazole, and itraconazole). Enteral nutrition difficulty indicates nasogastric or nasojejunal tube usage, and in more serious cases, surgical methods such as gastro- or jejunostomy.

Omics-Inferred Partitioning and Expression of Diverse Biogeochemical Functions in a Low-O2 Cyanobacterial Mat Community.

ABSTRACTCyanobacterial mats profoundly influenced Earth’s biological and geochemical evolution and still play important ecological roles in the modern world. However, the biogeochemical functioning of cyanobacterial mats under persistent low-O2 conditions, which dominated their evolutionary history, is not well understood. To investigate how different metabolic and biogeochemical functions are partitioned among community members, we conducted metagenomics and metatranscriptomics on cyanobacterial mats in the low-O2, sulfidic Middle Island sinkhole (MIS) in Lake Huron. Metagenomic assembly and binning yielded 144 draft metagenome assembled genomes, including 61 of medium quality or better, and the dominant cyanobacteria and numerous Proteobacteria involved in sulfur cycling. Strains of a Phormidium autumnale-like cyanobacterium dominated the metagenome and metatranscriptome. Transcripts for the photosynthetic reaction core genes psaA and psbA were abundant in both day and night. Multiple types of psbA genes were expressed from each cyanobacterium, and the dominant psbA transcripts were from an atypical microaerobic type of D1 protein from Phormidium. Further, cyanobacterial transcripts for photosystem I genes were more abundant than those for photosystem II, and two types of Phormidium sulfide quinone reductase were recovered, consistent with anoxygenic photosynthesis via photosystem I in the presence of sulfide. Transcripts indicate active sulfur oxidation and reduction within the cyanobacterial mat, predominately by Gammaproteobacteria and Deltaproteobacteria, respectively. Overall, these genomic and transcriptomic results link specific microbial groups to metabolic processes that underpin primary production and biogeochemical cycling in a low-O2 cyanobacterial mat and suggest mechanisms for tightly coupled cycling of oxygen and sulfur compounds in the mat ecosystem.IMPORTANCE Cyanobacterial mats are dense communities of microorganisms that contain photosynthetic cyanobacteria along with a host of other bacterial species that play important yet still poorly understood roles in this ecosystem. Although such cyanobacterial mats were critical agents of Earth’s biological and chemical evolution through geological time, little is known about how they function under the low-oxygen conditions that characterized most of their natural history. Here, we performed sequencing of the DNA and RNA of modern cyanobacterial mat communities under low-oxygen and sulfur-rich conditions from the Middle Island sinkhole in Lake Huron. The results reveal the organisms and metabolic pathways that are responsible for both oxygen-producing and non-oxygen-producing photosynthesis as well as interconversions of sulfur that likely shape how much O2 is produced in such ecosystems. These findings indicate tight metabolic reactions between community members that help to explain the limited the amount of O2 produced in cyanobacterial mat ecosystems.

Wettability alteration by surface adsorption of asphaltene molecular in carbonate porous media

In this study, the effect of four asphaltene samples on the wettability alteration of carbonate reservoir rock is investigated. The wettability of each core, before and after the deposition of asphaltene, is evaluated using two methods: relative permeability and contact angle. Normally, core samples got oil-wet after the asphaltene deposition, and the contact angle on the surface increased. However, the degree of wettability of each crude oil was different based on the asphaltene composition. According to the elemental analysis of asphaltene samples, the H/C index alone cannot show the asphaltene adsorption potential. The sulfur is an element that enhances asphaltene-asphaltene interaction, but weakens calcite-asphaltene interaction. The oxygen can also enhance the adsorption of asphaltene to calcite, depending on the functional group and its location in the molecule. According to the results of the FTIR spectrum of asphaltene and rock powder, there are three main mechanisms for adsorption of asphaltene to calcite surface, followed by wettability alteration. The first mechanism is the electrostatic interaction between asphaltenes and calcite, which is because of the poly-aromatic nature of asphaltene. The intensity of the electrostatic interaction between asphaltene and rock is directly related to the aromaticity and condensation index of asphaltene. The second mechanism is dispersion, in which the side alkyl chain in the aromatic rings causes asphaltene to be adsorbed into the surface of the rock. The intensity of this mechanism is also proportional to the aliphatic index and the long chain index of asphaltene. The third mechanism, which is less important than the two above-mentioned ones, is the hydrogen bond that is proportional to the ROH index, calculated from the FTIR spectrum. To study the relationship between the electrostatic property of the surface after asphaltene adsorption with surface wettability, zeta potential was used. The results showed that asphaltene, because of its acidic nature, adsorbed to the calcite surface, would make its zeta potential negative. However, more negative zeta potential will not necessarily increase the contact angle. In other words, the surface wettability and electrostatic properties of the surface are two distinct categories that do not have a clear relationship. The surface wettability is more dependent on the amount of aromaticity index of asphaltene, whereas the electrostatic property of the surface is a function of the percentage of oxygen and sulfur compounds in the asphaltene structure. Finally, the scanning electron microscopy (SEM), along with the elemental analysis, was used to investigate the dispersion of various elements at the calcite surface after wettability alteration. The calcium and oxygen are the main elements of calcite production; therefore, the elemental mapping indicated that the surface would be covered with calcium and oxygen prior to the deposition of asphaltene (CaCO3). But by asphaltene deposition on the rock surface, calcium will be observed scattered in some points. For this reason, the amount of calcium in the elemental mapping can be related to the level of surface wettability, so that the lower the percentage of calcium in the surface, the more the asphaltene is adsorbed into calcite, and the changes in the contact angle is greater.

Molecular composition of halobenzoquinone precursors in natural organic matter in source water

Halobenzoquinones (HBQs) are emerging disinfection byproducts generated during the reaction of chlorine disinfectant with natural organic matter (NOM) in source water. In this study, the correlations between molecular weight and HBQs generation of river NOM was evaluated. The compositional and functional characteristics of primary HBQs precursors were revealed by using Orbitrap mass spectrometry combined with molecular tagging. The NOM fraction larger than 50 kDa resulted in approximately 9 times more HBQs (50.9 ± 2.7 ng/mgC) than low molecular weight fractions. Significant correlations were found between the yields of HBQs and lignin-like and highly oxygen compounds in NOM, suggesting their critical roles in HBQs formation. Derivatizating the aldehydes, ketones, hydroxyl and carboxyl groups in NOM could reduce HBQs yields by 90.7%–100%. Unraveling the molecular characteristics of HBQs precursors in NOM would greatly benefit the prediction of HBQs yields of different source water, and develop more efficient disinfection byproduct control strategies.

Insights of mineral catalytic effects of high ash coal on carbon conversion in fluidized bed Co-gasification through FTIR, XRD, XRF and FE-SEM

This study presents the synergy of high ash coal with different biomass when blended in different ratios for co-gasification using a fluidized bed gasifier. The moisture, CO2, oxygen, hydrogen and numerous other compounds have synergetic effects on the co-gasification because of affinity to heat and prone to reaction. The mineral constituents, discrete mineral species and ion-exchangeable elements present in coal, biomass and bottom ash residue have been identified by XRD, XRF, FTIR and SEM-EDX. The catalytic effects of mineral, major oxides, halides and chlorites content on co-gasification have been assessed. The mineral (e.g. calcite, dolomite, hematite, etc.) present in the high ash coal and biomass plays a catalytic role. Other minerals (e.g. quartz, sulfide, kaolinite and phosphates) negatively influence co-gasification and product gas composition. The positive relationship of CaO, MgO and Fe2O3 with CCE, CGE and increasing heat values also supports major oxides catalytic role. The blend of press mud and high ash coal has given better results due to more Ca, K, Mg and Na elements. SEM microphotographs reveal catalytic effects at the micro-level, indicated by the extensive cracking of hydrocarbon compounds. The empirical models proposed for estimation of catalytic effects of minerals on co-gasification.

Deeper investigation of oxygen-containing compounds in oleaginous feedstock (animal fat) by preparative column chromatography and comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry

The production of renewable fuels as biodiesel and bio-jet fuel is usually originated by the transformation and processing of oleaginous feedstocks, mainly composed of triacylglycerols. Currently, a significant part of the triacylglycerol production relies on grassy oil crops or other woody oil plants, representing more than 120 million metric tons every year. Considering that the worldwide triacylglycerol demand is expected to rise in the future, alternative routes are necessary to ensure a sustainable biodiesel industry and limit diesel price volatility. In this context, the use of animal fats could be an interesting alternative for biodiesel production as the production of animal byproducts represents nearly 17 million tons per year in the European Union only (2020). Animal fats, however, contain large amounts of no-esterified fatty acids and other oxygen compounds, reducing the yield of biodiesel. Therefore, a specific pretreatment is needed before the trans-esterification process. The setup of such appropriate pretreatments requires detailed upstream characterization of the minor components present in the feedstock. For this purpose, the minor component profile of animal fat was investigated by comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry. This was preceded by an innovative sample fractionation and focalization of these minor components by a preparative liquid chromatographic column method. The overall method permitted to extract different levels of information from the two-dimensional chromatograms, leading to a tentative identification of more than 150 compounds, mainly oxygenated, belonging to different chemical classes.

Py-GC-MS Study on Catalytic Pyrolysis of Biocrude Obtained via HTL of Fruit Pomace

Herein, we proposed new two-stage processing of blackcurrant pomace toward a value-added, hydrocarbon-rich biocrude fraction. The approach consisted of thermochemical liquefaction of a wet-type organic matter into liquid biocrude followed by its upgrade by thermal and catalytic pyrolysis. Particularly, we put effort into investigating the effect of selected catalysts (ZSM-5 and HY zeolite) on the composition of the volatiles released during the pyrolysis of the biocrude. The latter was obtained through liquefaction of the raw material in the binary solvent system of water and isopropanol. The biocrude yield accounted for ca. 45 wt.% of the initial dry biomass. It was a complex mixture of various component groups with an abundant share of oxygenates, especially carboxylic acids and esters. Thereafter, the biocrude was subjected to a pyrolysis study performed by means of the microscale coupled pyrolysis-gas chromatography-mass spectrometry technique (Py-GC-MS). The dominant components identified in the catalytic pyrolytic volatiles were unsaturated hydrocarbons (both cyclic and aliphatic ones) and, to a lesser extent, oxygen and nitrogen compounds. The addition of the ZSM-5 and HY zeolite allowed us to attain the relative total share of hydrocarbons in the volatile fraction equal to 66% and 73%, respectively (in relation to identified compounds). Thus, catalytic pyrolysis over zeolites seems to be particularly prospective due to the promotion of the deoxygenation reactions, which manifested in the noticeable decrease in the share of oxygen compounds in the evolved volatiles. The developed innovative two-stage processing of blackcurrant pomaces allows for obtaining value-added products that could serve as chemicals, biocomponents, and self-contained biofuels as well as bioplastic precursors. The presented contribution brings some new insights into the field of valorization of residuals generated by the food industry sector.

A comparative study of different rare-earth (Gd, Nd, and Sm) metals doped ZnO thin films and its room temperature ammonia gas sensor activity: Synthesis, characterization, and investigation on the impact of dopant

Zinc oxide and rare earth (Gd, Nd, and Sm) doped zinc oxide thin film has been synthesized chemically by facile and cost-effective SILAR method. The impact of rare-earth doping on structural, morphological, and optical properties of ZnO films has been investigated using various characterization techniques. The stylus profiler method is employed to find the thickness of the films. The doping of rare earth elements reduces the thickness of the films. The XRD and SEM results suggest that the rare-earth metal is successfully incorporated into the ZnO lattice. The elemental mapping and EDS results show that homogeneous scatter of zinc (Zn), oxygen (O), gadolinium (Gd), neodymium (Nd), and samarium (Sm) compounds are found in the doped films. The transmission and bandgap of the films are enhanced due to doping. The doped ZnO films have exhibited significant enhancement in ammonia gas sensors at room temperature. Nd doping is effective than the Sm doped ZnO and Gd doped ZnO to sense the ammonia in terms of recovery time, response time, and sensitivity.

Molecular chemodiversity of water-soluble organic matter in atmospheric particulate matter and their associations with atmospheric conditions

Water-soluble organic matter (WSOM) is a complex mixture of organic compounds affecting global climate change and carbon cycle. Herein, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used for identification of WSOM molecular compositions in annual atmospheric particulate matter with diameters ≤10 μm (PM10). Totally 6538 unambiguous monoisotopic molecular formulas were assigned to WSOM with m/z values concentrating in 150–600 Da. The CHO compounds with high unsaturation degrees contributed most (51.7–52.1%) to WSOM in spring and summer. However, the S-containing compounds (CHOS and CHNOS) with higher O/C and H/C ratios accounted for 56.8–63.2% of WSOM in autumn and winter. Temperature (r = 0.82) and O3 (r = 0.89) showed higher correlation with CHO compounds, which were mainly aliphatics and highly unsaturated structures with high oxygen compounds (80.7–90.8%). The concentrations of SO42− (r = 0.33) and NO3− (r = 0.46) in PM10 both showed a positive correlation with the abundances of the S-containing compounds due to their direct participation in atmospheric reactions. Among them, 96–100% and 78–96% of the CHOS and CHNOS compounds were confirmed to be organosulfates (OSs) and nitrooxy-organosulfates (NOSs) by MS/MS analysis, respectively. These findings illustrate the strong association of atmospheric conditions with molecular chemodiversity of WSOM.

Catalytic Co-Cracking of Used Cooking Oil Methyl Ester and Polystyrene Waste for Gasoline-Rich Biofuel Over Mesoporous Al-MCM-41 Catalyst

Used cooking oil and packaging foam are typical waste materials that are abundantly available as household and fast food restaurant waste with high energy content, thus representing potential feedstock for conversion into an alternative energy source. In this study, catalytic co-cracking was examined at 300°C in atmospheric pressure to generate fuel products with gasoline-like properties from a mixture of used cooking oil biodiesel and polystyrene pyrolysis oil. Mixture of ceramic powder and Al-MCM-41 was used as catalyst in comparison to a pristine mesoporous aluminosilicate material. The product distribution of produced biofuel wes analyzed by gas chromatography – mass spectrometry. Experimental results exhibit that catalytic co-cracking process generated up to 64,6 – 67,2% yield of liquid hydrocarbon. The product distribution and the quality of the resulting biofuel were significantly affected by Si/Al ratio of the catalyst. Pristine Al-MCM-41 with lower Si/Al ratio was more favored for the enrichment of gasoline range fraction (C7–C12) which give 88,98% yield, while Al-MCM-41/ceramic with higher Si/Al ratio only give 32,84% yield of gasoline fraction. Moreover, lower oxygenate compound with better stability of biofuel was also obtained using pristine Al-MCM-41 catalyst. The produced biofuel blend by both catalysts indicated promising physical properties including higher calorific value (53,2 and 52,4 MJ/kg) and higher-octane number (RON 99,8 and 95,5) than commercial gasoline.

Impacts of Syngas Composition on Anaerobic Fermentation

Energy consumption places growing demands on modern lifestyles, which have direct impacts on the world’s natural environment. To attain the levels of sustainability required to avoid further consequences of changes in the climate, alternatives for sustainable production not only of energy but also materials and chemicals must be pursued. In this respect, syngas fermentation has recently attracted much attention, particularly from industries responsible for high levels of greenhouse gas emissions. Syngas can be obtained by thermochemical conversion of biomass, animal waste, coal, municipal solid wastes and other carbonaceous materials, and its composition depends on biomass properties and gasification conditions. It is defined as a gaseous mixture of CO and H2 but, depending on those parameters, it can also contain CO2, CH4 and secondary components, such as tar, oxygen and nitrogenous compounds. Even so, raw syngas can be used by anaerobic bacteria to produce biofuels (ethanol, butanol, etc.) and biochemicals (acetic acid, butyric acid, etc.). This review updates recent work on the influence of biomass properties and gasification parameters on syngas composition and details the influence of these secondary components and CO/H2 molar ratio on microbial metabolism and product formation. Moreover, the main challenges, opportunities and current developments in syngas fermentation are highlighted in this review.