Absence Of Sulfur Research Articles

Impact of Sulfur Deficiency and Excess on the Growth and Development of Soybean Seedlings.

Sulfur is a critical element for plant growth and development, serving as a component of amino acids (cysteine and methionine), iron-sulfur clusters, proteins, glutathione, coenzymes, and auxin precursors. Deficiency or low concentrations of sulfur in the soil can lead to significant growth retardation in plants. The objective of our study was to examine the effects of sulfur (S) deficiency and excess on morphological symptoms, sulfur and nitrogen (N) metabolism, as well as antioxidant activity in soybean. We found that S starvation decreased the fine root length, biomass, and activity, and the chlorophyll content was reduced, while excess sulfur promotes lateral root growth. In contrast to sulfur excess, sulfur deficiency inhibits N and S metabolism levels in both subsurface and above-ground parts, and induced the expression of some sulfur transporters (SULTRs). In this study, we created soybean hairy root lines overexpressing the SULTR gene (GmSULTR2;1a) to observe metabolic changes following sulfur deficiency treatment. The results showed that GmSULTR2;1a saved the sulfur-deficient phenotype, and the antioxidant enzyme activity was much higher than that of the wildtype in the absence of sulfur. Our study revealed the important role of sulfur element in soybean growth and development and the regulation of sulfur deficiency by GmSULTR2;1a.

Evaluating the reinforcing potential of enzymatic cellulose nanocrystals in polypropylene nanocomposite

Cellulose nanocrystals (CNCs) produced through enzymatic hydrolysis exhibit physicochemical properties that make them attractive as eco-friendly reinforcing agents in polymer composites. However, the extent of their efficacy within a polymeric matrix is yet to be fully established. This study investigated the reinforcing capabilities of enzymatic CNC (approximately 3 nm in diameter) isolated from bleached eucalyptus Kraft pulp (BEKP), focusing on its application in polypropylene (PP) nanocomposites produced by injection molding. The study compared the performance of this enzymatic CNC (1–5 % wt) with PP composites reinforced with micro-sized cellulose fibers (BEKP at 10–30 % wt, approximately 13 μm) and additionally with commercial CNC produced by sulfuric acid hydrolysis. Despite enzymatic CNC experiencing agglomeration during spray-drying, leading to an average diameter increase to 3 μm, it still significantly increased the crystallization and glass transition temperature of the PP matrix. However, this agglomeration likely hindered the improvement of the mechanical properties within the nanocomposites. The results also showed that enzymatic CNC provided higher thermal stability at lower reinforcement levels compared to BEKP, but this came with a reduction in stiffness, posing a significant consideration in composite design. The addition of a coupling agent greatly enhanced the dispersion of reinforcements and the interfacial adhesion within the matrix, contributing to the enhanced performance of the composite properties. Additionally, enzymatic CNC demonstrated potential for superior reinforcement efficacy compared to commercially available CNC produced by sulfuric acid hydrolysis. In conclusion, enzymatic CNC exhibited a promising role as nano-reinforcement for thermoplastic polymer nanocomposites, exhibiting higher thermal properties at lower reinforcing loads than traditional micro-sized fiber reinforcements. The absence of sulfur, coupled with its higher thermal stability and sustainable potential, positions enzymatic CNC as a particularly favorable choice for applications involving direct contact with food, cosmetics, pharmaceuticals, and biomedical materials.

Synthesis of diesel‐like fuels using waste cooking oil and waste polyethylene via Co‐pyrolysis process

AbstractThis study investigated the effects of different proportions of waste polyethylene (WP) and waste cooking oil (WCO) on the chemical and physical properties of the resulting co‐pyrolysis oil produced in an indigenously developed laboratory‐scale fixed bed batch‐type reactor. The proportion of WCO was altered in increments of 10% from 10% to 90%, and correspondingly, the proportion of WP was adjusted from 90% to 10% (by weight). The highest liquid fuel yield, reaching 70.9% by weight, was achieved using a 40:60 ratio of WCO to WP (W40P60) at a constant heating rate of 12°C and a temperature of 500°C. The obtained fuel exhibits promising properties, including a high calorific value (max HHV around 45.63 MJ/kg) and other advantageous properties such as low viscosity, low oxygen and nitrogen content, and absence of sulfur. Fourier‐transform infrared spectroscopy (FTIR) and gas chromatography–mass spectroscopy (GCMS) were examined on the resulting liquid fuel. The GC–MS spectra predominantly display alkanes, constituting approximately 41% by weight, and alkenes, making up roughly 20% by weight. These analyses revealed properties akin to commercial diesel, emphasizing the potential of waste cooking oil and waste polyethylene proportions in liquid diesel like fuel production.

Synthetic diesel from biomass by Fischer-Tropsch synthesis

The production of liquid hydrocarbons fuel from biomass by Fischer-Tropsch synthesis has become more and more attractive due to its advantages compared to fossil diesel: environmental friendliness by recycling wood and agricultural wastes and reducing emissions of greenhouse gases (CO, CO2 ,SO2,NOx,unburned hydrocarbons and particulate matters), absence of sulphur and nitrogen, higher combustion efficiency, higher cetane number and also the compatibility with existing diesel engines and infrastructure. In this paper the Fischer-Tropsch synthesis process from biomass applied at the Güssing plant was investigated. Each stage of the installation: biomass gasification, gas cleaning and Fischer-Tropsch process, in terms of the equipment used and the parameters necessary for the synthesis, was analysed and discussed. Also, during the synthesis the gas composition of the syngas before and after each stage was analysed, using gas chromatography. The same analytical method was used in order to determine the carbon distribution of the Fischer-Tropsch fuels obtained in the process. The ASF model was applied and an α value of 0.89 was calculated for the products.

The thermal instability of hydrogen-substituted graphdiyne and its role in lithium-sulfur batteries.

This study reveals the role of thermal instability in hydrogen-substituted graphdiyne (HsGDY) and its impact on lithium-sulfur (Li-S) battery performance. HsGDY undergoes significant chemical and physical transformations when subjected to thermal heating, both in the presence and absence of sulfur. Our findings suggest that the structural transformation of HsGDY into a graphene-like structure is primarily responsible for enhancing sulfur trapping and reducing the polysulfide shuttle effect, rather than the previously hypothesized alkyne-sulfur chemical interactions.

A Review of Properties, Engine Performance, Emission Characteristics and Material Compatibility Biodiesel From Waste Cooking Oil (WCO)

Biodiesel is one of the renewable energy sources, non-fossil. The chosen feedstock should ideally be low-cost. Using waste cooking oil can reduce synthetic biodiesel's price by up to 70%. However, biodiesel has the advantage of lower heating value and higher density, causing increased fuel consumption and NOx emissions. Biodiesel has physicochemical properties such as a more significant cetane number than fossil diesel, a high flash point, and the absence of sulfur. This study identifies the potential availability of WCO as biodiesel and summarizes recent studies on the physiochemical properties of WCO biodiesel. This study also aims to clarify the use of WCO biodiesel on engine performance and exhaust emission characteristics (H.C., CO, CO2, NOx) when this biodiesel is used. Engine type and biodiesel ratio were identified for all articles. This study also discusses the effect of adding nanoparticles on engine performance and exhaust emissions in WCO biodiesel. This study also clarifies material compatibility (corrosion, wear, and friction). The corrosion rate in various types of materials and corrosion testing methods. Finally, this paper presents the opportunity for WCO biodiesel to be very feasible to reduce fossil diesel use.

Robust, thermally conductive and damping rubbers with recyclable and self-healable capability

Traditional crosslinked rubbers cannot be reprocessed or recycled due to their permanent covalent crosslink bonds. A facile and effective method is used to construct ionic hydrogen bonds and coordination bonds in carboxylated nitrile rubber (XNBR), obtaining robust, thermally conductive and damping rubbers with reprocessable and self-healable capability. P-phenylenediamine modified graphene oxide is used to crosslink XNBR in the absence of sulfur and other crosslinking agents. With the increase of modified graphene content, the crosslink density of XNBR increases, the damping properties are improved, and the thermal conductivity increases. The modified graphene is also a reinforcing filler, and XNBR/modified graphene composites exhibit good mechanical properties. XNBR/modified graphene/CuSO4 composites have good mechanical properties, self-healing and reprocessing capabilities because of the existence of dynamic ionic hydrogen bonds and coordination bonds. This facile and effective approach to preparing damping rubbers with self-healing and reprocessing capability opens a promising pathway to fabricate sustainable, multifunctional and high-performance damping materials.

Experimental Investigation for Determining an Ideal Algal Biodiesel-Diesel Blend to Improve the Performance and Mitigate Emissions Using a Response Surface Methodology.

The ongoing depletion of the world's fossil fuel sources and environmental damage has compelled the quest for alternative energy. Excellent characteristics of biodiesel include its renewable nature, safety, absence of sulfur, environmental advantages, and biodegradability, which can eradicate the above problems. In this study, algal oil was characterized to obtain the fatty acid profile, and the free fatty acid value of algal oil suggested a two-step process of esterification and transesterification for efficient biodiesel production. The performance and emission results of biodiesel and its blends (B10, B20, and B30) were investigated in a constant speed, single-cylinder, 4-stroke, 3.5 kW compression ignition engine at different loads for arriving at an appropriate fuel blend ratio. The response surface methodology technique is used to predict the ideal composition of microalgae-diesel using the experimental data with due weightage for the optimization criterion. The predicted blend ratio of B25 was tested on the engine and authenticated. The findings recorded an improvement in brake thermal efficiency to 31.42% and reduction in brake specific energy consumption to 9.82 MJ/kW h, unburned hydrocarbon to 85 ppm, carbon monoxide to 0.164% v/v, carbon dioxide to 4.115% v/v, nitrogen oxides to 691 ppm, and smoke opacity to 16.93%.

DABCO-Catalyzed Reaction of 2-Naphthols with Aryl Isothiocyanates: Access to 2-Iminonaphtho-1,3-oxathioles.

2-Naphthols 1 were found to react with aryl isothiocyanates 2 to provide 2-iminonaphtho-1,3-oxathioles 3 in the presence of DABCO as a catalyst. When elemental sulfur was used, moderate to good yields of 3 could be achieved from a nearly equimolar mixture of two starting materials 1 and 2. Products 3 could also be formed in the absence of sulfur or an external oxidant. In the latter case, an additional equivalent of 2 was found to act as a dehydrogenating agent.

Archaeometallurgical characterisation of ancient copper slags from pre-Harappan site, Kunal, India.

The copper slags collected during the excavation of the Early Harappan period site at Kunal in northern India were studied to understand the advancement of smelting technology and the achieved smelting temperature in the furnace by undertaking archaeometallurgical characterisation of the slags. In this research, two types of slags such as slag with glassy appearance and granulated slag were selected for the study. The microscopic structure and distribution of slag components were investigated using optical microscopy and phase determination was done by X-ray diffraction (XRD). Chemical characterization of the slags was conducted using scanning electron microscopy-energy-dispersive X-ray spectroscopy, X-ray fluorescence analysis (XRF) and inductively coupled plasma-mass spectrometry to build a complete chemical profile of the slags. Fayalite and magnetite were the dominant phases in the glassy slag; however, the granulated slag showed the dominance of calcite as secondary phase which reflected the dolomitic stoichiometry of the slag. The presence of dominant fayalite mineral phase as detected by XRD and higher concentration of iron as detected by XRF indicated the reducing environment during the smelting process. In this study, the absence of sulphur is reported which is unique to the ancient copper slag.

Effects of 3d transition metal impurities and vacancy defects on electronic and magnetic properties of pentagonal Pd2S4: competition between exchange splitting and crystal fields

In this paper, we first investigate the electronic properties of the two-dimensional structure of dichalcogenide Pd2S4. These properties strongly depend on the crystal field splitting which can change by atomic vacancies (S and Pd vacancies). The main purpose of the present paper is to create remarkable magnetic properties in the system by adding 3d transition metal atoms where the presence of Mn, Cr, and Fe creates the exchange interaction in the system as well as change in the crystal field. The created magnetic properties strongly depend on the competition between exchange interaction and crystal field to separate the levels of d orbitals. In addition, the presence of the transition metals in the structures with S and Pd vacancy has been investigated carefully. The calculations demonstrate that we can achieve an extensive range of magnetic moment up to 3.131 {mu }_{B}. The maximum one is obtained in the presence of Mn and absence of sulfur while some of the doped structures does not have magnetic moment. Our results show that Pd vacancy in the presence of Cr, Mn and Fe metals increases the magnetic property of the Pd2S4 structure. The extensiveness and variety of the obtained properties can be used for different magnetic and non-magnetic applications.

Synthesis and characterization of a novel composites derived from SBA-15 mesoporous silica and iron pentacarbonyl

HypothesisFe(CO)5 was deposited on SBA-15 from gaseous phase and the adsorbed iron precursor was oxidized and hydrolyzed. We hypothesize that a novel method produces composites of unique and useful properties. The absence of sulfur and halides in the composites is of special importance with respect of their potential application as catalysts and catalyst supports. ExperimentsWe obtained composites containing 1.3–157.5% of iron oxide with respect to silica (counted as 100%). The new materials were characterized by specific surface area, XRD (X-ray diffraction), Mossbauer spectroscopy, electron microscopy coupled with EDS (energy dispersive X-Ray spectroscopy), and microelectrophoresis. FindingsIn the composites low in iron (<57% of iron oxide) the Mossbauer spectra showed only doublets, which were interpreted as tiny nanoparticles of Fe(III) oxide in the pores of SBA-15. In the composites high in iron (>65%) the Mossbauer spectra showed doublets and sextets. The later were interpreted as larger nanocrystals of hematite, and the presence of such nanocrystals was confirmed by XRD. EDS confirmed that in the composites low in iron, iron oxide was evenly distributed in the entire volume of pores of SBA-15.

Effects of nanopores and sulfur doping on hierarchically bunched carbon fibers to protect lithium metal anode

AbstractStudies on three‐dimensional structured carbon templates have focused on how to guide homogeneous lithium metal nucleation and growth for lithium metal anodes (LMAs). However, there is still insufficient evidence for a key factor to achieve their high electrochemical performance. Here, the effects of nanopores and sulfur doping on carbon‐based nanoporous host (CNH) electrode materials for LMAs were investigated using natural polymer‐derived CNHs. Homogeneous pore‐filling behaviors of lithium metal in the nanopores of the CNH electrode materials were first observed by ex situ scanning electron microscopy analysis, where the protective lithium metal nucleation and growth process led to significantly high Coulombic efficiency (CE) of ~99.4% and stable 600 cycles. In addition, a comparison study of CNH and sulfur‐doped CNH (S‐CNH) electrodes, which differ only in the presence or absence of sulfur, revealed that sulfur doping can cause lower electrochemical series resistance, higher CE value, and better cycling stability in a wide range of current densities and number of cycles. Moreover, S‐CNH‐based LMAs showed high electrochemical performance in full‐cell Li–S battery tests using a sulfur copolymer cathode, where a high energy density of 1370 W h kgelectrode−1 and an excellent power density of 4120 W kgelectrode−1 were obtained.

Hot corrosion of TBC‐coated components upon combustion of low‐sulfur fuels

AbstractGas turbine reliability is a crucial requirement for passenger safety in aviation and a secure energy supply. Hence, corrosive degradation of combustor parts, vanes, and blades in gas turbines must be prevented. One of the most severe forms of corrosion is alkali‐sulfate‐induced hot corrosion, which is associated with internal sulfidation of components and is usually anticipated to fade in importance in the absence of sulfur. However, the literature suggests that hot corrosion might still occur in low‐sulfur combustion gases. In this study, established thermodynamic modeling methods are used to analyze the low‐sulfur hot corrosion regime. Liquid sodium chromate is found to be stable in these conditions. A comparison of calculation results and engine findings suggests that high alkali levels can negatively impact thermal barrier coating life even if sulfur is absent in the fuel. Laboratory tests are carried out to validate the chromate formation on MCrAlY‐coated specimens. It is shown that molten sodium chromate can alter the oxidation behavior of MCrAlY, promoting the formation of voluminous spinel. This represents a new and different form of hot corrosion compared to type I hot corrosion.

Light-scattering properties of microorganisms Desulfuromonas acetoxidans by influence of silver

The article deals with the concentration changes and relative content of bacterial cells of Desulfuromonas acetoxidans in the intervals of sizes 0.2–2.0 µm under the influence of nano silver particles. Correlation between these changes of light-scattering properties of bacterial cells and growth abilities of bacteria Desulfuromonas acetoxidans under inflence of silver nanoparticles and ions has been shown. The purpose of the work was to research the intensity of processes the change of indexes of the antioxidant system the cells of Desulfuromonas acetoxidans at influence of silver nanoparticles and silver nitrate. The influence of various concentrations of silver nanoparticles and silver nitrate on enzymatic activity of catalase and reduced glutathione synthesis by Desulfuromonas аcetoxidans cells under their cultivation with fumarate addition and with absence of sulphur has been determined. Specific catalase activity increased with enhancing of concentration and duration of bacterial cultivation under the addition of this salt. The highest specific catalase activity was determined on the second day of bacterial growth under the influence of all concentration range of investigated metal salt. The reduced glutathione content under silver nitrate and silver nanoparticles exposure varied depending on the cultivation time and metal concentration. The maximum reduced glutathione content has been observed. The result of catalase activity changes and glutathione content changes of sulfur-reducing D. acetoxidans bacteria cell-free extracts and has been investigated under the influence of different concentrations of Ag nanoparticles during four days of cultivation has been investigated.

Toward morphology development and impact strength of Co-continuous supertough dynamically vulcanized rubber toughened PLA blends: Effect of sulfur content

In this study, supertough dynamically vulcanized blends (DV) of polylactide (PLA) and acrylonitrile butadiene rubber (NBR) are prepared. Effects of sulfur content on the compatibility, interfacial adhesion, morphology and impact resistance are investigated. NBR presents in spherical droplets dispersed in the PLA phase in absence of sulfur. With addition of sulfur, however, NBR tends to present in a continuous phase formed by numerous microfibril-like elongated vulcanized rubber, whereas the DV with 3 phr sulfur demonstrates a more uniform co-continuous structure. Correspondingly, the DV exhibits a sharp brittle-ductile transition occurs as the sulfur content increases from 1.5 to 2.5 phr, and the DV with 3 phr achieves an impact strength of almost 30 times that of neat PLA. This work aims to illustrate the development of network-like dispersion of vulcanized rubber in PLA-based DVs, and the findings provide a useful guideline in future exploration of PLA-based DVs.

OBTAINING A BOILER FUEL COMPONENT FROM THE SECONDARY POLY-PROPYLENE

The article proposes to increase the level of properties of boiler fuel - fuel oil, by its compounding with the product obtained by thermal destruction of secondary polypropylene materials. Thermal destruction of polypropylene raw materials was carried out in the laboratory, in a reactor-type apparatus at a final destruction temperature of 395 °Cand a pressure of 0,11 MPa, thus obtaining a product / component with boiling points from 160–240 °C to 360 °C. Studies of the physicochemical parameters of this product / component have shown that it has improved low temperature properties, high flash point and characterized by the absence of sulfur. It has been found that as the boiling point of a product / component increases, its viscosity, flash point and pour point increases due to the removal of low-boiling fractions. Increasing the boiling point of the component leads to a decreasing in its mass yield, which, ultimately, also affects the increasing of its cost. The values of the informative factor calculated for the quality indicators used in determining the quality of the product / component showed that the most informative indicators, the use of which is appropriate in further research in this direction are kinematic viscosity, flash point and solidification.The obtained product / component can be used either to improve the properties (low temperature properties, sulfur reduction) of commercial boiler fuel, or to bring substandard fuel to the requirements of DSTU and TU.

Influence of the Ir content and the support on the thiotolerance of the Ir/SiO2‐Al2O3 catalysts for selective ring opening of decalin

AbstractThe influence of Ir content on sulphur tolerance for the selective ring opening of decalin was investigated. Ir/SiO2‐Al2O3 catalysts (70 wt% and 80 wt% SiO2) were used. In the absence of sulphur, slight differences were observed on the yields according to the metallic content regardless of the support used. Although the results of cyclopentane hydrogenolysis showed that the metallic function acquires importance as the metal content increases, for these metal percentages the acid function limits the rate of decalin opening reaction. Products distribution are strongly modified using decalin with S content compared to pure decalin. The formation of dehydrogenated products is virtually null due to S adsorbed on the metal sites. The support has low influence on the thiotolerance. The results, related to the amount of S per Ir surface atom, showed that for a moderate S content (S/Irsurf ∼ 0.30), 1.5 Ir/Sy appears to be less poisoned than 1Ir/Sy and 2Ir/Sy.

Phenol-derived products from fast pyrolysis of organosolv lignin

Lignin is the largest aromatic bio-polymer feedstock with a huge potential of being refined for aromatic chemical platform and building block. Organosolv process for lignin extraction has a low impact on the environment due to its low chemical requirement, the absence of sulfur, and as it is more practical for chemical recovery. Therefore, refinement of extracted lignin to valuable molecular compounds such as purified lignin and its derivative is the key success for biorefinery industry. In this study, sugarcane bagasse from a local sugar manufacturer in Thailand, noted as BG-lignin, was selected as feedstock for lignin extraction using ethanol and water. The chemical composition of this lignin was slightly different than that of commercially available organosolv lignin, noted as Comm-OS-lignin, in that BG-lignin has more combustible constituents (volatile organic compounds and fixed carbon) of 96.14% and low ash content of 0.09%. The chemical structure of BG-lignin contains a higher number of aliphatic hydrocarbon and aliphatic hydroxy side chains than Comm-OS-lignin, as confirmed by the FT-IR and 1H-NMR analyses. The study on fast pyrolysis of lignin, using Py-GCMS technique, found 2, 3-dihydrobenzofuran as a major constituent at any tested pyrolysis temperature. H-unit, G-unit, and S-unit are distributed in resemble fraction with a H∕G∕S ratio of 1∕1∕0.7 and 0.8∕1∕1 for Comm-OS-lignin and BG-lignin, respectively, at pyrolysis temperature of 400–600 °C, except for H-unit which was enhanced at 700 °C to 28.82% of Comm-OS-lignin and 29.66% of BG-lignin. At a temperature of 400–600 °C, phenolic selectivity of pyrolyzed products, mainly methoxy phenol (Ph-OCH3) and alkylated phenol (R-Ph-OCH3), was done. A higher pyrolysis temperature of 700 °C led to the elimination of aromatic side group and is more favorable in alkyl phenol (R-Ph) and phenol selectivity. However, reduction of the phenolic compound was observed with a higher temperature due to thermal fragmentation of the C–C linkage in the aromatic structure. Products selectivity related to lignin feedstock and pyrolysis temperature could be applied as a conceptual guideline for conducting further study of chemical upgrading process to obtain high-value biochemical products.

Catalytic performance stability of Mo, W and Re-based sour water–gas shift catalysts

It has been shown in our previous findings that Mo-, W- and Re-based catalysts promoted with Ni, Co, and K are considered as a promising tri-component catalyst for sour WGS reaction. In order to evaluate the stability of the formed active sulfide and oxysulfidic species at sulfided Mo-, W- and Re-based catalysts at the same surface density of the main component, namely 2 atoms metal/nm2 γ-Al2O3 support, under influence of oxidizing agents as H2O steam and CO2, the WGS reaction was proceeded in absence of sulfur in gas feed. With the intent to enable a quick check, the applied approach was to perform the WGS reaction at high reaction temperature, 400 °C, in H2S-free syngas and varying the gas hourly space velocity (GHSV). This study gave information about the behaviour of sour molybdenum, tungsten and rhenium WGS catalysts during operation accident. It was found that the active sulfide and oxysulfidic species are more stable in absence of sulfur in feed at tri-component KCoMo and KCoRe catalysts. These catalysts possess lowest sulfur dependence of WGS activity and stability of the deactivation, which is an indication of the applicability of these two systems as optimal sour water–gas shift catalysts.