Sulfur Resources Research Articles

Conversion of polysulfides on core–shell CoP@C nanostructures for lithium–sulfur batteries

Lithium–sulfur batteries (LSBs) have received considerable attention due to their high theoretical energy density, low cost, and abundant sulfur resources. However, the shuttle effect and slow redox kinetics seriously hinder the development of LSBs. To resolve these issues, one-dimensional (1D) porous carbon-encapsulated CoP (CoP@C) nanotube-like nanostructures were rationally designed and successfully prepared through a simple two-step hydrothermal reaction. The CoP quantum dots in this structure can not only capture polysulfides, but also electrocatalyze the conversion of polysulfides. The electrocatalytic effect of CoP was systematically investigated by electrochemical tests. The experimental results and DFT calculations consistently revealed the fundamental mechanism of chemically anchoring lithium polysulfides (LiPSs) by CoP, the polysulfide conversion pathway, and the precipitation behavior of Li2S. Meanwhile, the as-prepared CoP@C/MWCNT/S electrode achieved a high initial discharge capacity of 1237.6 mAh/g at 0.5C, retained 92.3 % of the capacity and a high Coulombic efficiency (nearly 100 %) after 100 cycles, and exhibited an outstanding rate capability at as high as 5C. This work reveals the application potential of cobalt phosphide materials in the development of advanced LSBs.

Quantum-Mechanical Driven 1H Iterative Full Spin Analysis Addresses Complex Peak Patterns of Choline Sulfate.

Choline and choline esters are essential nutrients in biological systems for carrying out normal functions, such as the modulation of neurotransmission and the formation and maintenance of cell membranes. Choline sulfate is reportedly involved in the defense mechanism of accumulating sulfur resources against sulfur deficiency. Contrary to expectations, a full assignment of the 1H NMR spectrum of choline sulfate has not been reported. The present study pioneered a full assignment by quantum-mechanical driven 1H iterative full spin analysis. The complex peak patterns were analyzed in terms of heteronuclear and non-first-order coupling. The 1H-14N coupling constants, including two-bond coupling, which can be neglected, were accurately determined by iterative optimization. Non-first-order splitting has been described to be due to the presence of magnetically non-equivalent geminal protons. Moreover, in the comparison of the methylene proton resonance patterns of choline sulfate with choline and choline phosphate, the differences in the geminal and vicinal coupling constants were further examined through spectral simulation excluding the heteronuclear coupling. The precise spectral interpretation provided in this study is expected to contribute to future 1H NMR-based qualitative or quantitative studies of choline sulfate-containing sources.

Urea-modified Cu-based materials: Highly efficient and support-free adsorbents for removal of H2S in an anaerobic and dry environment

In this work, we report a novel urea-modified copper-based material (XUrea@Cu) obtained by directly calcinating a mixture of urea and copper nitrate. This material enables the efficient purification of H2S under dry and anaerobic conditions. The performance test results showed that the H2S capacity of the optimal adsorbent (2Urea@Cu) could reach 364.2 mg(H2S)∙gsorbent-1, which is much superior to those of other adsorbents in the literature. Further study demonstrates that the ultra-desulfurization performance of 2Urea@Cu is mainly attributed to the extensive alkaline site, the high concentrations of active oxygen, and the abundance of oxygen vacancy; which are quite effective for capturing H2S (acidic and strong reducibility). Interestingly, the deactivation adsorbent (De-2Urea@Cu) is mainly composed of high-purity CuS, which means that the Urea@Cu adsorbent can simultaneously achieve efficient purification of H2S and recovery of sulfur resources since CuS is a valuable product. In addition, in-situ FT-IR and theoretical calculation results indicate that H2S molecules dissociate on the CuO(111) surface by stepwise dehydrogenation, while S combines with adjacent Cu to form CuS. The consumption of active components (CuO) and the accumulation of reaction products (CuS) are the primary reasons for the deactivation of adsorbents. Considering the simple preparation process, low cost, and excellent H2S adsorption activity, these urea-modified copper-based materials are very promising H2S adsorbents.

锂硫电池非均相电催化剂

<p indent="0mm">With the rapid development of electronic transportation and portable electronics, commercial lithium-ion batteries would be unsatisfactory to meet the needs of future markets owing to the relatively low energy density. Seeking a reliable substitution system is becoming imperative. Lithium-sulfur (Li-S) battery has been recognized as a cutting-edge energy storage system because of its high theoretical capacity (1672 mAh g^–1) and cost-effectiveness of sulfur resources. Nevertheless, the severe shuttle effect and sluggish reaction kinetics significantly restrict its further commercialization. In the developing history of Li-S batteries, physical confinement and chemical adsorption have often been employed to achieve the anchoring of polysulfides. However, these strategies are still difficult to fully solve the problems of slow reaction kinetics and poor cycle performance. Recent years have witnessed the introduction of heterogeneous electrocatalysts into the Li-S system, which readily meets with great success in suppressing the shuttle effect and elevating the reaction kinetics. In this review, we introduce the basic reaction of Li-S battery and point out the main challenges in its current development stage, followed by summarizing the effects of electrocatalysts. Firstly, the polar electrocatalyst is able to effectively adsorb polysulfide and inhibit its diffusion in the electrolyte. Secondly, the electrocatalyst can effectively promote the conversion of polysulfide and improve the utilization rate of sulfur species. Thirdly, the uniform distribution of active sites in the electrocatalyst also contributes to the uniform deposition of short-chain polysulfides. In addition, the concepts and comparisons of homogeneous and heterogeneous electrocatalysts are presented, manifesting the essential significance of heterogeneous electrocatalysts in Li-S system. Homogeneous electrocatalysts usually refer to small soluble organic molecules with the same phase state as soluble polysulfides in the reaction system. Homogeneous electrocatalysts have more specific catalytic sites, whilst heterogeneous electrocatalysts have more diverse morphologies and higher possibility of multi-site synergistic catalysis. Then the common regulation strategies for heterogeneous electrocatalysts are classified, including vacancy regulation, doping regulation, heterostructure modulation, size control, and phase modulation. In further contexts, the underlying mechanisms of different regulation strategies for promoting polysulfide conversion are discussed. The introduction of heterogeneous electrocatalysts can effectively promote the reaction kinetics and improve their electrochemical performance. However, there are still many obstacles waiting to be solved in the practicability of Li-S batteries. For instance, there is a lack of highly selective and stable electrocatalysts. The identification of real catalytic sites in the electrocatalysts still remains unclear. Moreover, Li-S batteries have poor performance under lean electrolyte and low lithium consumption. In view of these issues, future development strategy is put forward from four aspects, encompassing material exploration, precise synthesis, characterization methods and practical application, aiming to bridge the gap between the reality and ideal in working Li-S batteries.

A Facile Immobilization Strategy for Soluble Phosphazene to Actualize Stable and Safe Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) have attracted extensive attention owing to their high energy density and abundant sulfur resources. However, LSBs are still restricted by the unsatisfactory electrochemical performance resulting from the shuttle effect of lithium polysulfide (LiPSs), and the potential fire hazard caused by inflammable ether electrolytes and polyolefin separators. Herein, a facile immobilization strategy for hexachlorocyclotriphosphazene (HCCP) is creatively applied to address the above issues simultaneously. Insoluble HCCP cross-linked microspheres (H-CMP) are firstly obtained at ambient temperature using tannic acid (TA) as a cross-linking agent and then a multifunctional separator coating is constructed based on H-CMP. The released phosphorus-related radicals from H-CMP in wide temperatures effectively prevent the combustion of electrolytes and separators, and hence improve the fire safety of the Li-S pouch cell. Furthermore, H-CMP availably chemisorbs LiPSs to interdict the shuttle effect, thereby dramatically improving the electrochemical performance of LSBs. The effectiveness of this strategy is also verified in high sulfur loading (6.38mg cm-2 ), high temperature (50 °C), and Li-S pouch cells. More importantly, H-CMP exhibits sufficient stability for Li metal and suppression of Li dendrites. This facile immobilization strategy for multifunctional phosphazenes provides a competitive option for the large-scale fabrication of high-safety and high-performance LSBs.

Application of machine learning methods for estimating and comparing the sulfur dioxide absorption capacity of a variety of deep eutectic solvents

Sulfur dioxide (SO 2 ) is one of the main atmospheric pollutants and an active threat to human health. SO2 separation from industrial flue gases improves air quality, decreases human health problems, and reserves sulfur resources. The capturing and recycling processes demand a green solvent with an effective, selective, and reversible SO 2 absorption. Deep eutectic solvents (DESs) have recently been engaged in SO 2 capture/recycle processes. The SO 2 removal capacity of DESs depends on their ingredients (the hydrogen bond donor, hydrogen bond acceptor, water content), temperature, and pressure. Despite comprehensive experimental investigations, literature presents no clue to compare the SO 2 absorption capacity of DESs considering their compositions and operating conditions. Therefore, this work deploys an efficient machine learning model to estimate the SO 2 absorption capacity of DESs as a function of their molecular weight, water content, pressure, and temperature. All the laboratory-measured datasets reported in the literature have been included to ensure that the deployed model is reliable and generalized. Furthermore, the proposed model has been selected among five different classes of artificial neural networks . A single hidden-layer neural network with only eleven neurons optimized by the Levenberg-Marquardt is the most precise model predicting 480 DES-SO 2 phase equilibria with the mean squared error , mean absolute percentage error, and coefficient of determination of 1.13 × 10 −3 , 4.76%, and 0.97936, respectively. This research is the first step toward constructing a reliable model for screening available DESs based on their SO 2 absorption capacity and finding the best candidate. • Two scenarios have been followed for estimating the SO 2 solubility in 29 DESs. • Various machine learning techniques were designed/compared to find the best model. • Systematic ranking analyses confirm that the MLP-LM is the highest accurate model. • The model shows excellent performance, i.e., R 2 = 0.97936, MSE = 1.13 × 10 −3 , MAPE = 4.76%. • Trend analyses confirm that the MLP-LM has compatibility with the system behavior.

Removal of hydrogen sulfide in biogas from wastewater treatment sludge by real-scale biotrickling filtration desulfurization process

Abstract The biological removal of hydrogen sulfide in biogas is an increasingly adopted alternative to conventional physicochemical processes because of its economic and environmental benefits. In this study, a real-scale biotrickling filtration (BTF) process packed with polypropylene carrier was used to investigate the removal of high concentrations of H2S in biogas from an anaerobic digester. The results show that H2S in biogas was entirely removed under different inlet concentrations of H2S from 2,923 to 4,400 ppmv, and the elimination capacity of H2S in the filter achieved about 52.71 g H2S/m3/h). In addition, the process efficiency was found to be independent of the inlet H2S concentration. The removal of high concentrations of H2S in biogas was accomplished by the BTF process with SOB (Acidithiobacillus thiooxidans), which is active in the acidic environment (pH 1.5–3.5). In addition, the process efficiency was found to be independent of the inlet H2S concentration. Consequently, a real-scale BTF process allowed the potential use of biogas and the recovery of elemental sulfur resources simultaneously.

Electrochemical polymerization of nonflammable electrolyte enabling fast-charging lithium-sulfur battery

Lithium-sulfur battery has received wide interest owing to its high theoretical energy density and abundant sulfur resources. Sulfurized pyrolyzed poly(acrylonitrile) (S@pPAN) cathode can eliminate the shuttle effect owing to solid-solid conversion mechanism while suffers poor electrolyte/electrodes interphase and sluggish kinetics in carbonate electrolyte. Herein, an in-situ electrochemical polymerization is firstly proposed to form a nonflammable polyether electrolyte for Li-S@pPAN battery, which enables superior lithium compatibility (over 3000 h) and modifies the cathode interphase with promoted kinetics. The polyether-rich interphase ensures high capacity (1645.3 mAh g−1 based on sulfur), fast-charging ability (10 C) and remarkable cycling stability (99.5% retention over 400 cycles) with ultrahigh average Coulombic efficiency (CE) over 99.9995%, indicating nearly no irreversible reaction on cathode. The pouch cell delivers high sulfur utilization of 91.2% and stable performance with 84.6% capacity retention over 60 cycles.

Not Mining Sterilization of Explored Mineral Resources. The Example of Native Sulfur Deposits in Poland Case History

The sterilization of mineral resources makes considerable amounts inaccessible for future use and may be a barrier to the free supply of commodities. During the exploitation of mineral deposits, some parts of their resources become sterilized as inaccessible because of natural hazards or unfavorable economic conditions. Not mining land use and the social opposition against mining is the purpose of sterilization of considerable demonstrated mineral resources of deposits not yet engaged in exploitation. The native sulfur deposits in Poland are a good example of such “not mining” sterilization, which makes a considerable part of known resources inaccessible. On the northern border of the Carpathian Foredeep within the Miocene gypsum formation, the systematic exploration had demonstrated about 1 billion tons of sulfur resources located in the deposits of varied dimensions. The sulfur opencast mining and underground melting (the modified Frasch method) flourished from 1958 up to 1993. The increasing sulfur supply, recoverable from hydrocarbons, caused the closing down of sulfur mines, leaving a place with considerable untouched resources. About 67% of sulfur resources left by closed mines and of other explored but not exploited deposits are sterilized by the advancement of settlements, industrial plants, road construction, and by social opposition against mining.

Green and efficient sulfur dioxide removal using hydrogen peroxide in rotating packed bed reactor: Modeling and experimental study

In order to reduce SO2 emissions and achieve green utilization of sulfur resources, a desulfurization method of SO2 removal using hydrogen peroxide (H2O2) in rotating packed bed (RPB) is proposed. It can not only achieve the efficient removal of SO2, but also lead to the effective utilization of sulfur resources. A mathematic model was first developed to describe the reaction and mass transfer process between H2O2 and SO2 in RPB. The influences of different operating conditions including RPB rotating speed, H2O2 mass fraction, gas–liquid volumetric flow rate ratio, gas flux, and inlet SO2 concentration on desulfurization performance were studied. Under the optimized conditions, it turned out that the desulfurization efficiency was above 99% and the outlet SO2 concentration was ultra-low, below 35 mg/m3. The validity of the model was confirmed by the fact that most of the predicted desulfurization efficiency agreed well with the experimental result with a deviation within 5%. The height of mass transfer unit HTU for RPB is calculated to be 1.60–2.07 cm, which is one order of magnitude lower than that of conventional reactors, indicating the investment of the desulfurization reactor can be greatly reduced by using RPB.

N-Rich Carbon Catalysts with Economic Feasibility for the Selective Oxidation of Hydrogen Sulfide to Sulfur.

The efficient removal of hydrogen sulfide (H2S) from exhaust emissions is a great challenge to chemical industries. Selective catalytic oxidation of H2S into elemental sulfur is regarded as one of the most promising approaches to alleviate environmental pollution, while recycling sulfur resources. It is therefore highly desirable to develop efficient catalysts for the conversion of H2S to sulfur under mild reaction conditions. Here we present a nitrogen-rich carbon obtained by the direct thermal treatment of commercial polyaniline (PANI) for the selective oxidation of H2S in a continuous way at relatively low temperature (180 °C). The efficient conversion of H2S over the N-rich carbon catalysts was attributed to the in situ generation of pyridine-N on the carbon matrix, which served as the active sites to promote the absorption and dissociation of H2S molecules, achieving a superior catalytic conversion rate of 99% and selectivity up to 95% at 180 °C.

Co-doped ZnS with large adsorption capacity for recovering Hg0 from non-ferrous metal smelting gas as a co-benefit of electrostatic demisters.

The installation of electrostatic demisters (ESDs) makes possible the use of sorbent injection technology for recovering Hg0 from non-ferrous smelting gas. ZnS, as a typical smelting raw material, could be a promising candidate due to the sulfur boding site for mercury. However, the low reaction rate and poor adsorption capacity limited its application. In this study, Co was incorporated into ZnS to enhance adsorption activity for recovering Hg0. Co0.2Zn0.8S exhibited the best Hg0 capture performance among the modified sorbents. The Hg0 adsorption capacity was up to 46.01mg/g at 50°C (with 50% breakthrough threshold), and the adsorption rate was as high as 0.017mg/(gmin). Meanwhile, SO2 and H2O had no poison effects on Hg0 adsorption. The chemical adsorption mechanism was proposed, which was Co3+, and sulfur active sites could immobilize Hg0 in the form of stable HgS, following a Mars-Maessen reaction pathway. The spent sorbent will release ultrahigh concentration mercury-containing vapor through the heating treatment, which facilitated centralized recovery of Hg0. Meanwhile, inactivated sorbent can be used as smelting raw material to recover sulfur resources. Therefore, the control of Hg0 emission from non-ferrous smelting gas by Co-adopted ZnS was cost-effective and did not form secondary pollution. Graphical abstract.

An investigation into the precipitation of copper sulfide from acidic sulfate solutions

Due to the local and global supersaturation of metal sulfides in aqueous solutions, the industrial metal sulfurization processes using soluble sulfur resources (Na2S/Na2S2O3/(NH4)2S/H2S) and elemental sulfur have insurmountable defects, including the unfilterable fine precipitates, weak chemical selectivity, high reagent toxicity, and generation of soluble polysulfides. In order to develop a cleaner and green sulfurization method, a surface/heterogeneous sulfurization system using wetted sulfur particles and sulfur dioxide was investigated through single-factor experiments and reaction mechanism tests. The results of disproportionation tests indicated that reaction parameters, such as temperature, powder contact angle, SO2 pressure and molar ratio of Cu-to-Sulfur, significantly affected the reaction efficiency. The reaction is mixed controlled by the temperature and powder contact angle. During the disproportionation‑sulfurization process, the total reaction rate for the generation of HS− ions is dependent upon: the liquid diffusion of SO2 absorption, the powder contact angle of wetted sulfur particles, and the nucleophilic reaction between SO3H− with sulfur. Meanwhile, the total reaction is a shrinking nuclear reaction which the particles sizes continuously increasing after the metal sulfides formed.

Efficient recovery of hydrogen and sulfur resources over non-sulfide based LaFexAl12-xO19 hexaaluminate catalysts by H2S catalytic decomposition

Simultaneous recovery of hydrogen and sulfur resources from acidic gas hydrogen sulfide (H2S), whose content may reach 20–100 % after hydrodesulfurization in oil refineries, is increasingly attractive. Nowadays, the widespread utilization of H2S decomposition technology is mainly restricted by the low hydrogen and sulfur yield, i.e. 20 % at 800 °C. In this work, for the first time a novel non-sulfide based LaFexAl12-xO19 hexaaluminate catalysts was used for high (50 %) hydrogen yield at 800 °C. At the same time, the active phases and reaction mechanism were confirmed by various characterization techniques. The XRD, Raman, XPS, Mössbauer and XAFS results verified that the Fe species in the hexaaluminate structure, especially octahedral-coordinated Fe3+, served as the main active phases. The reaction routes/mechanism for H2S decomposition were also verified by density functional theory (DFT) method. H2S was firstly adsorbed on the active sites and then completed the decomposition by direct dehydrogenation mechanism. Briefly, current study has minimized the challenges for H2S decomposition at industrial scale. It is anticipated that our findings will offer potential application of H2S decomposing technology.

Evaluation of the Solid Electrolyte Interphase Formed in Lithium Bis(trifluoromethylsulfonyl)Amide-Tetraglyme Solvate Ionic Liquids with Different Compositions

Rechargeable lithium-sulfur (Li-S) battery has attracted much attention because of abundant sulfur resources and low cost. Lithium polysulfides (Li2S x ) produced during discharge have been known to dissolve in conventional organic electrolytes, resulting in self-discharge due to shuttle effect. It has been found that the solubility of Li2S x is very low in the solvate ionic liquids (SILs) composed of lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) and tetraglyme (G4, CH3(OCH2CH2)4OCH3).1 Therefore, LiTFSA-G4 SILs are considered a promising electrolyte for rechargeable Li-S battery. We have reported deposition and dissolution of Li can be performed with the coulombic efficiency higher than 90% in LiTFSA-G4 SILs.2 The coulombic efficiency increased with an increase in the molar fraction of LiTFSA, suggesting the dissolved Li species might affect the morphology of Li deposits. On the other hand, formation of the solid electrolyte interphase (SEI) is considered unavoidable even in the LiTFSA-G4 SILs. In the present study, the SEI formed in the LiTFSA-G4 SILs with different compositions was evaluated with electrochemical impedance spectroscopy. The SILs were prepared by mixing LiTFSA and G4 at 50.0-50.0 and 54.5-45.5 mol%. The water content in the SILs was less than 50 ppm, which was determined by Karl Fischer titration. Cu was used as a substrate for the SEI formation and deposition of Li. The surface of the Cu substrate was electrolytically degreased before use. A silver wire immersed in 50.0-50.0 LiTFSA-G4 SIL containing 0.1 M AgCF3SO3 was used as a reference electrode for a three-electrode cell. Li foil was used as a counter electrode. Celgard 3501 was used as a separator for a 2032 coin-type cell. Electrochemical impedance spectroscopy was performed in the frequency range from 20 kHz to 1 Hz with an amplitude of 5 mVpp. The SEI was prepared on a Cu electrode by applying 0 V vs. Li|Li(I) in LiTFSA-G4 SILs. Semi-circles appeared in the Nyquist plots of the Cu electrode at 0 V vs. Li|Li(I) after formation of the SEI. The resistance of the SEI increased continuously during application of the potential within 2 hours, suggesting decomposition of the SILs was sluggish at room-temperature. The resistance of the SEI prepared by applying the potential for 10 minutes in 54.5-45.5 mol% LiTFSA-G4 SIL was smaller than that in 50.0-50.0 mol% one, indicating the ionic conductance and/or thickness of the SEI depends on the composition of the SIL. The coulombic efficiency for deposition (with the charge density of 0.2 C cm–2) and dissolution (with the cut-off potential of 2.0 V vs. Li|Li(I)) of Li using a coin-type cell at the current density of ±0.1 mA cm–2 with the open-circuit intervals of 10 minutes reached to the steady-state value close to 90% after four or five cycles. The coulombic efficiency for 54.5-45.5 mol% LiTFSA-G4 SIL was slightly higher than that for 50.0-50.0 mol% one, probably reflecting the difference in the SEI formed on the Cu electrode. On the other hand, the coulombic efficiency was found to be improved when a sufficient open-circuit interval was taken after deposition of Li in the first cycle, indicating it is important to take an enough reaction time for formation of the better SEI on the Cu electrode. Acknowledgment This study was supported by the Advanced Low Carbon Technology Research and Development of Program (ALCA) of the Japan Science and Technology Agency (JST). Reference K. Dokko, N. Tachikawa, K. Yamauchi, M. Tsuchiya, A. Yamazaki, E. Takashima, J.-W. Park, K. Ueno, S. Seki, N. Serizawa, and M. Watanabe, J. Electrochem. Soc.,160, A1304 (2013). N. Tachikawa, S. Hosoda, T. Ishida, K. Yoshii, M. Watanabe, and Y. Katayama, PRiME2016, Abst#558, Hawaii, (2016).

Confined and covalent sulfur for stable room temperature potassium-sulfur battery

Potassium-sulfur (K-S) battery represents one of the most promising electrochemical energy storage devices because of the low cost and abundance of potassium and sulfur resources, but the inferior cycle stability and high operating temperature seriously impede its applications. Herein, a high energy and stable room temperature K-S battery was developed with a confined ad covalent sulfur cathode, which could deliver an energy density as high as ∼445 Wh Kg−1, a Coulombic efficiency close to 100%, and a superior cycle stability with a capacity retention of 86.3% over 300 cycles at a voltage cut-off of 0.8–3.0 V. This work displayed a basic study on the rechargeable potassium-sulfur batteries and may pave the way for designing sulfur based electrode materials for potassium based ion batteries.

A Review of Functional Binders in Lithium–Sulfur Batteries

AbstractLithium–sulfur (Li–S) batteries have received tremendous attention due to their superior theoretical energy density of 2600 Wh kg−1, as well as the abundance of sulfur resources and its environmental friendliness. Polymer binders as an indispensable component in cathodes play a critical role in maintaining the structural integrity and stability of electrodes. Additionally, multifunctional polymer binders have been involved in Li–S batteries to benefit electrochemical performance by mitigating the shuttle effect, facilitating the electron/ion transportation, and propelling the redox kinetics. In the context of the significant impact of binders on the performance of Li–S batteries, recent progress in research on polymer binders in sulfur cathodes is herein summarized. Focusing on the functions and effects of the polymer binders, the authors hope to shed light on the rational construction of robust and stable sulfur cathode for high‐energy‐density Li–S batteries. Perspectives regarding the future research opportunities in Li–S batteries are also discussed.

Static and dynamic characteristics of SO2-O2 aqueous solution in the microstructure of porous carbon materials

Porous carbon material facilitates the reaction SO2 + O2 + H2O → H2SO4 in coal-burned flue gas for sulfur resources recovery at mild conditions. It draws a long-term mystery on its heterogeneous catalysis due to the complicated synergic effect between its microstructure and chemical components. To decouple the effects of geometric structure from chemical components, classical molecular dynamics method was used to investigate the static and dynamic characteristics of the reactants (H2O, SO2 and O2) in the confined space truncated by double-layer graphene (DLG). Strong adsorption of SO2 and O2 by the DLG was observed, which results in the filling of the solute molecules into the interior of the DLG and the depletion of H2O. This effect mainly results from the different affinity of the DLG to the species and can be tuned by the separation of the two graphene layers. Such dimension dependence of the static and dynamic properties like distribution profile, molecular cluster, hydrogen bond and diffusion coefficient were also studied. The conclusions drawn in this work could be helpful to the further understanding of the underlying reaction mechanism of desulfurization process in porous carbon materials and other applications of carbon-based catalysts.

Beyond Lithium-Ion: Lithium- Sulphur Batteries for Space?

Lithium-ion (Li-ion) batteries are established as the state of the art [1] rechargeable batteries for terrestrial and space applications today since the launch of Proba 1 satellite in 2001. [2]At the moment there is strong interest by all stakeholders related or influenced by the battery markets on two systems: The rechargeable Li-air (Li-O2 ) and Li-Sulfur (Li-S) batteries. There have been many studies on both technologies during the past decades but since major challenges are still to be overcome, none of the two technologies has been yet commercialized.Li-S is believed to reach mass commercialization towards the end of the decade whereas Li-O2 is expected to be available after 2030. Therefore, discussion to follow hereby will focus on Li-S.Li-S cells are regarded as one of the most promising systems for next generation batteries due to their high theoretical capacity, the abundant and low cost sulfur resources and lithium-ion comparable cathode production techniques. [RD3] If Li-S batteries were to be successfully developed and reach their theoretical maximum, batteries over six times lighter than the conventional lithium-ion ones, would be available. [RD4]Sion Power in the US and OXIS Energy Ltd. in Europe are the major companies producing Li-S cells.Prototype Cells were procured from Oxis Energy, UK and characterisation tests were performed at ESA-ESTEC Battery Life Test Facility in Noordwijk, Netherlands. The results are presented here, mainly in order to enhance basic understanding on existing technology in Europe and show relevant trends.Consequences at power system level, if this technology was to be adopted for satellite applications, are also addressed in this paper.

Kerosene biodegradation ability and characterization of bacteria isolated from oil-polluted soil and water

With increasing production and consumption of oil, the inevitable spillage of oil presents a significant challenge to protecting the environment and human health. Bioremediation is an effective approach to address this challenge. In this research, three soil and two wastewater samples contaminated by petroleum and a sample of crude oil were collected from Bandar Abbas Refinery, Iran. These samples were used for isolation and identification of bacteria, which can be used for cleaning polluted lands. Twelve strains were isolated and cultured at 28°C standard succinate medium from which carbon or sulfur resources were eliminated and kerosene was added. Three isolates were selected for identification because of their high growth rate in kerosene tests. The biodegradation activity of these bacteria was analyzed by gas chromatography. Using biochemical tests, 16S rDNA sequence, and API 20 E kit, it was revealed that these bacteria belong to Enterobacter cloacae, Enterobacter hormaechei, and Pseudomonas stutzeri. They were able to degrade 67.43%, 48.48%, and 65.48% of 5% kerosene as carbon source in seven days, respectively. Pseudomonas stutzeri and Enterobacter hormaechei could respectively degrade 54.14% and 12.98% of 10% kerosene as sulfur source in seven days. Hence, these bacteria can be considered as excellent candidates for petroleum biodegradation.