Low Sulfur Content Research Articles

A sustainable approach to managing city park waste through biochar as a renewable energy source

An abundant natural resource known as lignocellulosic biomass is seen to be a promising and sustainable alternative to renewable energy. A carbon-rich, porous substance called biochar is created when biomass is thermally decomposed during pyrolysis procedures in order to make biofuels. Biochar can be made in big industrial facilities or on a local scale. In order to limit the usage of fossil fuels and find a solution for managing urban park garbage, this project will examine the potential of biochar made from waste from city parks as a renewable energy source. A 25-gram natural zeolite catalyst was used to produce biochar at temperatures between 100 and 500 °C with sample weights of 50, 100, 150, and 200 grams. Calorimetric analysis, FTIR analysis, SEM analysis, XRF analysis, ultimate analysis, and proximate analysis are used to characterize the product. The results showed that the zeolite process produced the maximum calorific value of biochar at 6009.8 cal/gram, the highest yield of biochar at 200 °C, and the weight of 50 grams of biomass without a catalyst at 96%. Aliphatic OH and CH groups associated with phenols, alcohols, and carboxylic acids can be seen using FTIR analysis. Large holes can be seen in leaf litter biochar according to SEM examination. For biochar products, the XRF examination of the metal elements Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Co, Zn, Rb, Sr, Na, Mg, Sr, and Pb is within the permitted limits. Leaf waste can be converted into a non-toxic renewable energy source because biochar has a low sulfur concentration of 4.0%. The findings of this study are anticipated to fill in some gaps left by earlier studies, particularly with regard to the use of garbage from municipal parks and the advancement of renewable energy sources..

Possible Uses of Decommissioned Coke Batteries

Since the 80s of the 20th century, as a result of the reduction in demand for coke, economic crises and the availability of coking coal, the operations of coke plants in Europe have been ending. Furthermore, the pressure for using renewable energy sources continues to increase, including the production of fuels. In most cases, the current solution is to add biocomponents to fuels produced in the classical way from oil. There are considerations about reusing these coke batteries, this time for the production of liquid fuels. Therefore, this work is devoted to the processing of biomaterials mixed with brown coal by the pyrolytic process. Extracted rapeseed meal, sunflower seed husks and dry distillery grain with solubles (DDGS) were selected as biomaterials. They are waste material from various productions, but these materials also show good energy potential. The brown coal came from the ČSA quarry, which is characterized by a low content of sulfur and ash and also improves the properties of liquid pyrolysis products, because it reduces polarity of organic phase, which enables easier separation of the aqueous and liquid phases of the product. Pyrolysis experiments were carried out in two different pyrolysis devices - i) in a micropyrolysis unit (sample loading: in the order of mg, heating rate: 100 °C s-1, fast removal of pyrolysis products); ii) in the pilot unit (sample weight: approx. 10 kg, heating rate: 5.2 °C min-1 and slower removal of pyrolysis products, cuboid shape of the pyrolysis retort simulating a coke oven battery). On the basis of mass balances and characteristics of micropyrolysis products, the pyrolysis temperature for pilot experiments was set at 650 °C. Behind the pyrolysis retort of the pilot unit, a thermic-catalytic reactor (catalyst: sulfurized aluminosilicate based on Ni-W) was connected in order to improve the quality of volatile pyrolysis products. The highest yields of organic phases of liquid products came from co-pyrolysis of coal and DDGS and coal with rapeseed meal. However, the characteristics of organic phases determined as the most advantageous material for the pyrolytic processing the rapeseed meal (specifically a higher proportion of aliphatic and aromatic hydrocarbons, a lower proportion of hydrocarbons with heteroatoms and a higher proportion of light fractions). The most beneficial pyrolysis mixture contained 35 % of rapeseed meal and the temperature in the catalytic part of the thermic-catalytic reactor was 300 °C.

Ionic liquids based on metal halide complex salts and their applications in extractive desulfurization of liquid fuel: A review

In this review, different types of sulfur compounds (thiols, sulfides, benzothiophenes, etc.) present in liquid fuel can be conveted by combustion to sulphur dioxide, which is a prevailing source of environmental pollution, so many countries proposed standard S-content to lower than 10 ppm. Although, hydrocracking process produce low-sulfur content, but still needs more desulfurization, researches have done using many technologies, among that were: A: Adsorptive desulfurization (ADS), through adsorptive over such surfaces. B: Oxidative Desulfurization (ODS), using an oxidant agent to convert sulfure into form can be removed. C: Hydrodesulfurization process (HDS), which is most efficient than other methods to remove organo sulfur (aliphatic and aromatic). D: Bio desulfurization (BDS), employed microorganisms to remove sulfur atom from organic S-compounds and can be environmental friendly. E: Extractive desulfurization (EDS), is a prosses using solvent as liquid- liquid extraction. The above technologies faced some disadvenges such as nature of volatile molecular solvent coupled with limitation of loss solvent, difficult of extraction regeneration, environmental pollution and costly, as required industrial unit operation at high temperature and pressure beside the expensive of hydrogen gas and catalysts. Therefore, it has been a challenge research investigation to explore a new deep extractive desulfurization methods. Among these treatments was using ionic liquids (ILS) which composed of heterocyclic organic cation (imidazolium, pyridinium, etc.) and different inorganic anions my be applied to decrease temperature, non-toxic, chemical stability, environmental friendly as green solvent, so, (ILS) used for many applications and deep eutectic desulfurization among that. Recently, studies showed that metal contains ionic liquids for extractive sulphur removal have a high influence and ability for sulphur removal than metal free (ILS) , which may be a good solvent in separation and removal of aromatic sulphur from fuel. The Fe, Co, Ni, Zn, Cu, etc. metals halides were used with organic cation to form complexes salts. The mechanism was investigated that the metal (ILS) have almost good extraction ability explained by the complexation of metal moiety with sulfur compounds.

Elucidating the impact of sulfur precursors on the reactivity, toxicity, and colloidal stability of post-sulfidized nanoscale zerovalent iron

The sulfur precursor-induced sulfidation effectively enhances the nanoscale zerovalent iron (nZVI) reactivity. However, due to the batch-to-batch variation in synthesis and reaction conditions, the sulfur precursor that confers superior reactivity to sulfidized nZVI (S-nZVI) and its application potential are undetermined. This study evaluated the impact of six sulfur precursors (Na2S, Na2S2O4, S0, Na2S2O3, K2S6, and sulfate reduction effluent [a sulfide-containing effluent]) on the reactivity, toxicity, and colloidal stability of S-nZVI. The reactivity enhancement induced by sulfidation of the different sulfur precursors was inconsistent and dependent on the contaminant. In the removal of trichloroethylene (TCE) and hexavalent chromium Cr(VI) in aqueous solution, S-nZVI, with a high Fe0 content, hydrophobicity, and electron transfer properties (i.e., S-nZVINa2S and S-nZVINa2S2O3), yielded relatively high capacities. In the removal of tetracycline (TC) by S-nZVI, the performance was relatively unaffected by the sulfur precursors. The toxicity evaluation demonstrated that S-nZVIs showed a limited toxicity (less than 0.35-log) to Escherichia coli (E. coli) in simulated groundwater. Despite sulfidation marginally improving the colloidal stability of nZVI—by reducing the interparticle forces—, the S-nZVI particle settling was observed, within 60 min, at the bottom of the vial containing the suspension. Overall, none of the sulfur precursors was manifestly preferable to the others. Na2S, Na2S2O3, and SR-effluent were recommended for use in low sulfur content post-sulfidation processes considering the material performances and costs. These findings contribute to the understanding of the effect of the sulfur precursors on the reactivity and application potential of S-nZVI, thereby providing guidance for tuning S-nZVI properties and selecting suitable sulfur precursors for specific in situ remediation scenarios.

Mineralogical and geochemical compositions of the early permian coal in the Huixiang Mine, Dengfeng Coalfield, Henan, China: Occurrence modes and origins of NH4-illite

In this study, we investigated the mineralogy and geochemistry of the Pennsylvanian No. 21 coal seam at the Huixiang Mine in the Dengfeng Coalfield, North China by employing a range of analytical techniques, including electron probe micro-analysis, X-ray fluorescence spectrometry, inductively coupled plasma mass spectrometry, and X-ray powder diffraction. The No. 21 coal in Huixiang Mine is classified as semi-anthracite and is characterized by a low total sulfur and ash contents. The predominant minerals identified in the Huixiang coal are NH4-illite, kaolinite, calcite, and chlorite, alongside trace amounts of Al-hydroxide minerals, zircon, and pyrite. Coalification in the Huixiang Mine has been primarily influenced by the heat generated by gravity-gliding tectonic movements since the Yanshan period, and the presence of hydrothermal fluids. During the coalification process, organic nitrogen undergoes thermal ammoniation, releasing NH4+ ions that subsequently react with kaolinite, leading to the formation of NH4-illite. Concurrently, when kaolinite is converted into NH4-illite, the released Si and excess Al may provided the necessary material for the formation of Al-hydroxide minerals and chamosite. The coal in the Huixiang Mine is slightly enriched with Li, Zr, Nb, Ta, and Th, rendering it a promising candidate for potential industrial recovery. The strong correlation of these elements with ash content suggested that their presence was largely influenced by terrestrial material input, attributable to the source materials originating in the North Qinling Orogenic Belt.

Metal-Organic frameworks with two different metal centers for thiophene adsorption: Synthesis, characterization and mechanism analysis

Thiophene, widely found in fossil fuels, not only corrodes equipment but also causes great harm to the environment after combustion. Adsorptive desulfurization can deeply desulfurize fuels with low sulfur content and shows great development prospect. We experimentally studied the adsorption of thiophene and benzene in Cu-BTC and two types of IZE metal-organic frameworks (MOFs). By changing the temperature and concentration conditions, we compared the separation performance of MOFs with different metal centers. We found IZE-1 to have excellent s high thiophene adsorption capacity selectivity for thiophene adsorption at low thiophene concentration and (-up to 9.3 mg S/g MOF at 70 °C), superior to that of Cu-BTC. We performed first-principles calculations and elucidated the mechanism of thiophene adsorption by analyzing the electronic structure of MOFs. The molecular dynamics simulation further explains the high selectivity of thiophene adsorption and the adsorption process. This study demonstrates the potential for MOFs to be used in thiophene adsorption, particularly at high thiophene concentrations.

Sulfur and Cystine Content in Various Sheep Wool Breeds and Their Correlation with Wool Growth and Strength

This scholarly article presents a comprehensive analysis of sulfur and cystine content in the wool of various sheep breeds, with a particular focus on their relationship with wool growth and strength. The breeds under scrutiny include the Askanian fine-wool, Prekos, Latvian dark-headed, Ukrainian Carpathian mountain, and Karakul breeds. Our research revolves around wool samples extracted from the scapula area before the spring shearing process. Our findings reveal that the highest sulfur content is observed in the wool of Karakul sheep (3.05 %) and Prekos sheep (2.90 %), whereas the lowest sulfur content is noted in Latvian dark-headed sheep (2.65 %). Conversely, the highest cystine content is exhibited in the wool of Askanian fine-wool sheep (11.87 %) and Prekos sheep (11.46 %), while the lowest cystine content characterizes the wool of Karakul sheep (8.99 %) and the Latvian dark-headed breed (10.10 %). The genetic factors, specifically breed-specific characteristics, impact on the rate of wool growth. The most rapid growth rates are observed in Karakul sheep (873 mg/cm/day) and Askanian fine-wool sheep (857 mg/cm/day). Slightly lower growth rates are noted in Prekos breed sheep (844 mg/cm/day) and Ukrainian Carpathian mountain breed sheep (766 mg/cm/day). The lowest growth rates are recorded in Latvian dark-headed sheep (742 mg/cm/day). Furthermore, we establish that the highest tensile strength values are associated with the coarse wool of Karakul sheep (9.6 cN/tex) and the semi-coarse wool of Ukrainian Carpathian mountain sheep (9.3 cN/tex), as these fibers possess the thickest cuticular layer. Conversely, the lowest tensile strength values are observed in the wool of Latvian dark-headed sheep (7.0 cN/tex) and Prekos breed (7.1 cN/tex). An examination of the data reveals that there is no statistically significant correlation between the content of sulfur and cystine and the rate of wool growth. However, a robust direct correlational relationship is identified between the sulfur content and fiber strength (with correlation coefficients of r = 0.831 for Karakul breed sheep wool, 0.713 for Latvian dark-headed, 0.698 for Ukrainian Carpathian mountain, 0.544 for Askanian fine-wool, and 0.460 for Prekos breed wool).

Attenuation of wind intensities exacerbates anoxic conditions leading to sulfur plume development off the coast of Peru.

The release of vast quantities of sulfide from the sediment into the water column, known as a sulfidic event, has detrimental consequences on fish catches, including downstream effects on other linked element cycles. Despite being frequent occurrences in marine upwelling regions, our understanding of the factors that moderate sulfidic event formation and termination are still rudimentary. Here, we examined the biogeochemical and hydrodynamic conditions that underpinned the formation/termination of one of the largest sulfur plumes to be reported in the Peruvian upwelling zone. Consistent with previous research, we find that the sulfur-rich plume arose during the austral summer when anoxic conditions (i.e., oxygen and nitrate depletion) prevailed in waters overlying the upper shelf. Furthermore, the shelf sediments were organically charged and characterized by low iron-bound sulfur concentrations, further enabling the diffusion of benthic-generated sulfide into the water column. While these biogeochemical conditions provided a predicate to sulfidic event formation, we highlight that attenuations in local wind intensity served as an event trigger. Namely, interruptions in local wind speed constrained upwelling intensity, causing increased stratification over the upper shelf. Moreover, disturbances in local wind patterns likely placed additional constraints on wind-driven mesoscale eddy propagation, with feedback effects on coastal elemental sulfur plume (ESP) formation. We suggest ESP development occurs as a result of a complex interaction of biogeochemistry with regional hydrodynamics.

Comparing Life-Cycle Emissions of Biofuels for Marine Applications: Hydrothermal Liquefaction of Wet Wastes, Pyrolysis of Wood, Fischer-Tropsch Synthesis of Landfill Gas, and Solvolysis of Wood.

Recent restrictions on marine fuel sulfur content and a heightened regulatory focus on maritime decarbonization are driving the deployment of low-carbon and low-sulfur alternative fuels for maritime transport. In this study, we quantified the life-cycle greenhouse gas and sulfur oxide emissions of several novel marine biofuel candidates and benchmarked the results against the emissions reduction targets set by the International Maritime Organization. A total of 11 biofuel pathways via four conversion processes are considered, including (1) biocrudes derived from hydrothermal liquefaction of wastewater sludge and manure, (2) bio-oils from catalytic fast pyrolysis of woody biomass, (3) diesel via Fischer-Tropsch synthesis of landfill gas, and (4) lignin ethanol oil from reductive catalytic fractionation of poplar. Our analysis reveals that marine biofuels' life-cycle greenhouse gas emissions range from -60 to 56 gCO2e MJ-1, representing a 41-163% reduction compared with conventional low-sulfur fuel oil, thus demonstrating a considerable potential for decarbonizing the maritime sector. Due to the net-negative carbon emissions from their life cycles, all waste-based pathways showed over 100% greenhouse gas reduction potential with respect to low-sulfur fuel oil. However, while most biofuel feedstocks have a naturally occurring low-sulfur content, the waste feedstocks considered here have higher sulfur content, requiring hydrotreating prior to use as a marine fuel. Combining the break-even price estimates from a published techno-economic analysis, which was performed concurrently with this study, the marginal greenhouse gas abatement cost was estimated to range from -$120 to $370 tCO2e-1 across the pathways considered. Lower marginal greenhouse gas abatement costs were associated with waste-based pathways, while higher marginal greenhouse gas abatement costs were associated with the other biomass-based pathways. Except for lignin ethanol oil, all candidates show the potential to be competitive with a carbon credit of $200 tCO2e-1 in 2016 dollars, which is within the range of prices recently received in connection with California's low-carbon fuel standard.

Fischer–Tropsch Synthesis Catalysts for Selective Production of Diesel Fraction

The Fischer–Tropsch process is considered one of the most promising eco-friendly routes for obtaining synthetic motor fuels. Fischer–Tropsch synthesis is a heterogeneous catalytic process in which a synthesis gas (CO/H2) transforms into a mixture of aliphatic hydrocarbons, mainly linear alkanes. Recently, an important direction has been to increase the selectivity of the process for the diesel fraction. Diesel fuel synthesized via the Fischer–Tropsch method has a number of advantages over conventional fuel, including the high cetane number, the low content of aromatic, and the practically absent sulfur and nitrogen impurities. One of the possible ways to obtain a high yield of diesel fuel via the Fischer–Tropsch process is the development of selective catalysts. In this review, the latest achievements in the field of production of diesel via Fischer–Tropsch synthesis using catalysts are reviewed for the first time. Catalytic systems based on Al2O3 and mesoporous silicates, such as MCM-41, SBA-15, and micro- and mesoporous zeolites, are observed. Together with catalytic systems, the main factors that influence diesel fuel selectivity such as temperature, pressure, CO:H2 ratio, active metal particle size, and carrier pore size are highlighted. The motivation behind this work is due to the increasing need for alternative processes in diesel fuel production with a low sulfur content and better exploitation characteristics.

Growth Behavior, Biomass Composition and Fatty Acid Methyl Esters (FAMEs) Production Potential of Chlamydomonas reinhardtii, and Chlorella vulgaris Cultures.

The production of biomolecules by microalgae has a wide range of applications in the development of various materials and products, such as biodiesel, food supplements, and cosmetics. Microalgae biomass can be produced using waste and in a smaller space than other types of crops (e.g., soja, corn), which shows microalgae's great potential as a source of biomass. Among the produced biomolecules of greatest interest are carbohydrates, proteins, lipids, and fatty acids. In this study, the production of these biomolecules was determined in two strains of microalgae (Chlamydomonas reinhardtii and Chlorella vulgaris) when exposed to different concentrations of nitrogen, phosphorus, and sulfur. Results show a significant microalgal growth (3.69 g L-1) and carbohydrates (163 mg g-1) increase in C. reinhardtii under low nitrogen concentration. Also, higher lipids content was produced under low sulfur concentration (246 mg g-1). It was observed that sulfur variation could affect in a negative way proteins production in C. reinhardtii culture. In the case of C. vulgaris, a higher biomass production was obtained in the standard culture medium (1.37 g L-1), and under a low-phosphorus condition, C. vulgaris produced a higher lipids concentration (248 mg g-1). It was observed that a low concentration of nitrogen had a better effect on the accumulation of fatty acid methyl esters (FAMEs) (C16-C18) in both microalgae. These results lead us to visualize the effects that the variation in macronutrients can have on the growth of microalgae and their possible utility for the production of microalgae-based subproducts.

Geochemical and mineralogical evidence for the formation of siderite in Late Permian coal-bearing strata from western Guizhou, SW China

This paper presents the results of the geochemical and mineralogical investigation of siderite in the Late Permian coal-bearing strata from western Guizhou, SW China. Siderite occurs as fine-grained ooids, as recrystallized stellate-like forms, as ellipsoidal, rhombohedral, and oolitic aggregates, indicating their authigenic origin. In contrast, pore filling and veinlet siderite are of epigenetic origin. The low sulfur contents, absence of pyrite, and Sr/Ba ratios indicate that the siderite was deposited in a freshwater (non-marine) environment. The V/(V + Ni) values of studied samples, ranging from 0.68 to 0.86, indicate that the siderite developed under anoxic conditions. The presence of authigenic kaolinite and epigenetic siderite in the same samplesuggests that the chemical conditions changed from acidic to alkaline conditions during early diagenesis.Iron in the siderite was not only derived from silicate weathering of high-Ti basalts in the sediment source regions followed by transport as ions by ground and surface waters, but was also generated from in situ alteration of the Fe-bearing minerals within the peat itself. In addition, ascending hydrothermal solutions would also contribute some Fe, with the Fe probably sourced from the leaching of the basaltic basement. The presence of siderite-rich layers indicates enhanced chemical weathering rates in the sediment source regions. The δ13CPDB, δ18OPDB, and δ18OSMOW values of siderite in claystones and mudstones vary within the ranges of −7.7 to 5.8‰, −12.1 to −6.6‰, and 18.4 to 24.1‰, respectively, indicating that carbon and oxygen primarily originated from marine carbonate, dehydroxylation of organic matter, carbonate dissolution, and hydrothermal fluids. The released CO2 invoked the alteration of reactive silicate minerals in the sediments, and ultimately the formation of siderite. Circulating pore fluids dissolving iron, which is derived from the silicate weathering of high-Ti basalts in the sediment source regions and from in situ alteration of the Fe-bearing minerals within the peat, would transport some iron from the overlying peat into the underlying sediments, and the flow of fluids would be diminished or stopped at the base of the peat due to the mechanical barrier of the impervious claystone or mudstone layers. The ferrous iron was precipitated due to the alkaline environment conditions of the peat, by reaction with HCO3− dissolved in the waters to form siderite.

Co-pelletization of Hemp Residues and Agricultural Biomass: Effect on Pellet Quality and Stability

The rising interest in lowering the use of fossil fuels, which influence environmental pollution and global warming, is driving a substantial increase in renewable sources. Agricultural residues are the likely potential source for bioenergy generation. Some of them are already utilized for energy. Nonetheless, their potential is underutilized due to low biomass quality and high concentrations of sulfur and chloride, which induce the corrosion of adjoining equipment. However, their ash content and ash melting point make their utilization as renewable resources essential. Therefore, there is a need to find technologies to enhance biomass utilization for bioenergy processes. With the increase in hemp cultivation to extract phytocannabinoids, the amount of unused biomass has increased. The aim of this research was to investigate the use of hemp biomass for pellets and improve pellet quality by mixing them with lignin and oak sawdust. The results showed that the lowest amount of ash was found in pellets with 80% oak sawdust and 20% hemp residue compared with pellets made from mixtures of hemp residues, lignin, and oak sawdust. The highest calorific value was achieved by mixing hemp residues (20%) with lignin (80%).

A study on the desulfurization of sulfidic mine tailings for the production of a sulfur-poor residue

The mining industry generates large amounts of tailings every year. The most common destination for the tailings is deposition in tailings storage facilities (TSFs), which can have enormous dimensions. The management and storage of such large volumes of material pose many challenges in terms of dam stability and immobilization of hazardous contaminants that represent human-health and environmental risks, particularly for sulfide-containing materials. In addition, considerable amounts of precious and base metals can be lost in the tailings. Due to the economic value and growing industrial demand for precious and base metals, tailings may therefore be potential sources of secondary raw materials. This contribution investigates the flotation of pyrite-rich tailings, containing residual chalcopyrite, galena, and sphalerite, and high amounts of ultrafine particles. Flotation was used to recover the sulfide minerals and generate tailings with low sulfur content. The Cu-Pb-Zn-rich product could go to further treatment (e.g. (bio)hydrometallurgy) to recover the metals, while the low sulfur fraction could be used in the civil construction industry. Automated mineralogy (MLA) was used to provide quantitative mineralogical and textural data. Bench-scale experiments were performed by combining classic flotation and floc flotation (flotation of flocs of targeted minerals). Flotation of the material as received, as well as after classification into two fractions was performed. The samples as received and the coarser fraction (+37 µm) underwent classic flotation, while the finer fraction (−37 µm) was processed either by using the classic or the floc flotation approach. The flotation of the coarser particles provided higher sulfide recoveries, higher combined Cu-Pb-Zn grades in the concentrate (3.66%), cleaner residues (1.6% S), faster flotation rates, and reduced reagent consumption. Likewise, the results from the fine particle flotation allowed lower S content in the residues (3.4% S) as compared to the flotation of the original material. The results of the use of floc flotation for the finer fraction show an increase in the mass pull with a slight increase in the recovery of sulfides. Overall, the development of a route to process the tailings proved to be promising and the use of a two-route approach indicates advantages as compared to a single route.

Electrochemical Enhancement of Lithium-Ion Diffusion in Polypyrrole-Modified Sulfurized Polyacrylonitrile Nanotubes for Solid-to-Solid Free-Standing Lithium-Sulfur Cathodes.

The energy density of lithium-sulfurized polyacrylonitrile (Li-SPAN) batteries has chronically suffered from low sulfur content. Although a free-standing electrode can significantly reduce noncapacity mass contribution, the slow bulk reaction kinetics still constrain the electrochemical performance. In this regard, a novel electrochemically active additive, polypyrrole (PPy), is introduced to construct PAN nanotubes as a sulfur carrier. This hollow channel greatly facilitates charge transport within the electrode and increases the sulfur content. Both electrochemical tests and simulations show that the SPANPPy-1% cathode possesses a larger lithium-ion diffusion coefficient and a more homogeneous phase interface than the SPAN cathode. Consequently, significantly improved capabilities and rate properties are achieved, as well as decent exportations under high-sulfur-loading or lean-electrolyte conditions. In-situ and semi-situ characterizations are further performed to demonstrate the nucleation growth of lithium sulfide and the evolution of the electrode surface structure. This type of electrochemically active additive provides a well-supported implementation of high-energy-density Li-S batteries.

Drying of gypsum plaster prisms: prevention of visible sodium sulfate efflorescence through calcium formate addition

In this work, we investigated the drying process of a hardened gypsum plaster model (GP) that showed sodium sulfate efflorescence after subsequent exposure to water. Visible efflorescence could be prevented by adding small amounts of calcium formate (CF). Prism samples were prepared to investigate this observation, with an emphasis on chemical processes in the pore water. In the pure plaster, both sodium and sulfur accumulate at the surface of the prism, which leads to sodium sulfate precipitation. In the sample containing CF, calcium slightly accumulates at the surface, which leads to lower sulfur concentrations, because the porewater is in equilibrium with gypsum. Thermodynamic calculations show that higher sodium concentrations are then necessary to reach sodium sulfate supersaturation than without CF. These concentrations are not exceeded during early stages of the drying process, which ultimately leads to the sodium sulfate precipitation inside the prism. Therefore, sodium sulfate efflorescence can be hindered on gypsum plaster by the addition of CF.

In situ synthesis of S‐doped coal‐based carbon quantum dots and its application to Cr6+ detection

AbstractBACKGROUNDCoal‐based carbon quantum dots have better stability compared with other carbon quantum dots prepared from small molecules as carbon sources. Elemental doping can effectively improve the fluorescence performance of carbon quantum dots. However, the electronegativity difference between sulfur and carbon is small and the charge transfer between the two is very weak, so it is very difficult to dope sulfur onto carbon quantum dots by chemical methods. High sulfur content coal can achieve in situ synthesis of sulfur‐containing carbon quantum dots.RESULTSThe results showed that the prepared quantum dots had good stability and which increased with the increase of coal rank. CQDS is well dispersed, with an average particle size between 2.44 and 2.74 nm. It can emit light blue fluorescence under the UV excitation of 365 nm. It was found that trace amount of Cr6+ had a fluorescence quenching effect on CQDS and a good linear relationship was observed in the range of 0–100 μmol·L−1.CONCLUSIONQuantum dots doped with S atoms have better selectivity, interference resistance, and sensitivity in the detection of metal ions. The stability and the particle size of CQDS are increased with the coal rank. The quantum yield of CQDS prepared from high sulfur content coal is higher than low sulfur content coal which has same rank. The addition of Cr6+ to CQDS produces a dynamic fluorescence quenching. This study provides a new idea for the green preparation of coal‐based carbon quantum dots and the ion detection. © 2023 Society of Chemical Industry.

Thermo-catalytic reforming (TCR) of waste solid grade laminate

Thermo-catalytic reforming (TCR) is defined as intermediate pyrolysis at moderate temperatures and heating rates with subsequent reforming at elevated temperatures using biochar as a catalyst. TCR experiments were carried out to pyrolyze and subsequently reform Solid Grade Laminate (SGL) waste. SGL is a Kraft paper-derived product and as it is widely used in many applications, high volumes of waste laminate must be disposed of at end of life. To assess TCR for SGL waste treatment, the characterisation of the initial feedstock was accomplished, and it concluded that SGL is suitable to be processed via TCR. The main energy carrier products (char, oil and syngas) were generated by TCR in a 2 kg/h pilot-scale reactor under a pyrolysis temperature of 500 °C and reforming temperature of 650 °C, respectively. The mass balance analysis demonstrated that 50 wt% of the initial feedstock was comprehensively converted to syngas, 28 wt% to char and 22 wt% to a liquid fraction containing both water (17 wt%) and organics (5 wt%). The oil showed good properties as its HHV reached a value of 32.72 MJ/kg, with low oxygen and sulphur contents. However further processing is required for the fuels to be within suitable limits for use as drop-in fuels for vehicles. The syngas was found to be rich in hydrogen especially when pyrolysis temperature reaches its maximum. Lastly, char revealed a calorific value of 25.94 MJ/kg and was of a stable form of carbon, exhibiting potential as a feedstock for gasification or as a carbon capture and storage medium. TCR of SGL represents novelty as this feedstock has not been tested before in a pyrolysis/reforming system and it is a promising route in an optic of circularity. In waste valorisation, TCR oil has a great opportunity to be used as a fuel or blended with other conventional fuels, thus supporting the shift towards more sustainable mobility.

The comparison of 7.5 and 15% hydrogen peroxide as oxidizing agent in static tests of acid mine drainage potential in Indonesia

Static tests of acid mine drainage potential are an important part of mining water management. Net acid generation (NAG) test is widely used in Indonesian coal mines because of its convenience. This test uses H2O2 to oxidize sulfide minerals within rock samples to determine their net acid-forming capacity. This study aimed to determine the difference between H2O2 at concentrations of 7.5% (the standard in several Indonesian coal mines) and 15% (the standard of the Acid Rock Drainage Test Handbook and Indonesian National Standard) in categorizing rocks as potentially acid-forming and non-acid-forming and in terms of NAG solution characteristics. A total of 564 rock samples collected from two Indonesian coal mining sites were analyzed using pH, NAG, total sulfur, and acid-base-accounting tests. The results of the study showed that there was no significant difference in rock classification or the behavior of contaminants in the NAG solution between 7.5% and 15% H2O2. The characteristics of sulfide minerals in Indonesian coal mines were the main factors influencing the results of the NAG test and behavior of contaminants in the NAG solution. Therefore, H2O2 at a concentration of 7.5% can be used in Indonesian coal mines with relatively low total sulfur concentrations (<5%) and minerals in framboidal form.

THE IMPACT OF AGLOMERATION METHOD FROM AQUADES AND WASTE COOKING OIL TO THE INCREASING OF THE CALORIFIC VALUE AT PT MEGAPRIMA PERSADA’S COAL IN PT SURVEYOR INDONESIA LABORATORY, SAMARINDA EAST KALIMANTAN)

Coal is a fossil fuel that is formed from organic deposits. Coal reserves in Indonesia generally include low rank coal with a total moisture up to 40%. Coal with low ash and sulfur content can be obtained by utilizing oil and water which in this case is called agglomeration. In making agglomeration this time it is done by using waste cooking oil and aquades. The comparison used was 100 g of coal, 100 ml of distilled water and the variable that was distinguished was waste cooking oil, namely 20 ml, 30 ml and 40 ml. Proximate analysis results on coal obtained IM 11,93%, AC 7,04%, AC 39,79% and FC 41,24%. At 20 ml agglomeration obtained IM 0,47%, AC 6,04%, VM 51,94% and FC 41,55%. At 30 ml agglomeration, the value of IM is 0,37%, AC is 5,35%, VM is 67,38% and FC is 36,38%. At 40 ml agglomeration, the value of IM is 0,26%, AC is 4,76%, VM is 59,19% and FC is 35,79%.