Sulfur Shell Research Articles

Ferric methanesulfonate as an effective and environmentally sustainable lixiviant for Zn extraction from sphalerite (ZnS)

Zinc is currently extracted from sphalerite (ZnS) by either sintering-smelting or roasting-leaching. These high-temperature processes produce environmentally hazardous sulfur dioxide gas. Hence, sustainable zinc extraction calls for direct leaching at low temperatures. Here, we show that ferric methanesulfonate is a high performing lixiviant for this purpose. Using 0.8M ferric methanesulfonate, 99.3% Zn was extracted from 106−150μm sphalerite particles after leaching at 70°C for 96h. Elemental sulfur, rather than sulfur dioxide, was produced as a by-product. When compared to common inorganic lixiviants such as ferric sulfate or ferric chloride, ferric methanesulfonate demonstrates greater extraction efficiency and is less corrosive, less toxic, and does not release harmful gases. Mineralogical, microscopical, and compositional characterization of reaction products confirmed the formation of a core–shell structure consisting of a sphalerite core and a sulfur shell, and the manifestation of a coupled dissolution-reprecipitation mineral replacement mechanism. Efficient zinc extraction was facilitated by the interconnected pores in sulfur, which provided pathways for mass transfer between the lixiviant and sphalerite core. The precipitation of anglesite (PbSO4), which in some instances caused surface passivation through the infilling of sulfur shells, suggests that Pb2+ concentration should be controlled when applying ferric methanesulfonate for Zn extraction.

Well-Defined Hierarchically Porous Double-Shell Hollow Polypyrrole@Sulfur Microspheres with Outer Sulfur Shells for Lithium–Sulfur Batteries with Superior Electrochemical Performance

Polypyrrole (PPy) hollow micro/nanospheres have been widely designed to encapsulate active sulfur as cathodes in lithium–sulfur (Li–S) batteries to inhibit the polysulfide shuttle effect. Here, for...

Fabrication of conductive polymer-coated sulfur composite cathode materials based on layer-by-layer assembly for rechargeable lithium–sulfur batteries

Lithium–sulfur battery is a promising energy storage system due to its high specific energy density, low cost and environmental friendliness. Layer-by-layer (LbL) assembly technique is introduced as a simple method to fabricate polymer-coated sulfur cathode materials for rechargeable lithium–sulfur batteries. Conductive polyaniline (PANI) were assembled on the outer shell of sulfur particles to provide an electron conducting paths for the charge and discharge of lithium–sulfur battery. The low permeability of sulfur shells was obtained by assembling the enough number of polyelectrolyte bilayers. A crosslinker and heat treatment were utilized to further reduce its permeability. The assembled polymer shells can be expected to be permeable for Li+ and slowly or hardly for sulfur and polysulfide during charge and discharge process. The obtained sulfur composite cathode materials were characterized by four-point probe instrument, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectroscopy. The results demonstrated polymers have been coated on the surface of sulfur only by physical interaction and have no effect on sulfur. The conductive polymer-coated sulfur cathode also represents a well conductivity of 0.23Scm−1. Moreover, after coated by polymers, the crystal structure of sulfur still keeps its orthorhombic corresponding to cyclooctasulfur molecule (S8).

Preparation and performance of a core–shell carbon/sulfur material for lithium/sulfur battery

The core–shell carbon/sulfur material with high performance is prepared by a facile and fast deposit method in an aqueous solution. As sulfur ratio is 85% (w/w) in the composite, scanning electron microscope (SEM) and transmission electron microscope (TEM) observation show that the moniliform particles with 10 nm sulfur shells preserve the morphology of carbon cores. Tested as the cathode material in a lithium cell with binary organic electrolyte at room temperature, the composite shows excellent electrochemical performance. It exhibits a specific capacity up to 1232.5 mAh g −1 at the initial discharge and its specific capacity remained above 800 mAh g −1 after 50 cycles. Meanwhile, the composite also exhibits the high-rate behavior at 800 mA g −1 of current density. Assuming a complete reaction to the final product, Li 2S, the utilization of the electrochemically active sulfur is about 85% at the initial cycle. Electrochemical impedance spectroscopy (EIS) is introduced to understand the impact of the microstructure of composite on electrochemistry. According to our study, a novel core–shell structural carbon/sulfur material is proposed and the key factors of the preparation are discussed.

Zero m phonons in metal chalcogenide nanotubes

Phonon dispersions of single-wall MoS2 and WS2 nanotubes are calculated within a full symmetry implemented valence force-field model. Tubular structure is found to be characterized by two Raman active modes: by the in-phase breathing modes (in full analogy to carbon nanotubes) with frequency approaching Brillouin scattering domain (as diameter approaches nm), and by the high-energy breathing mode with sulfur shells breathing in phase, but out of phase relative to the Mo/W atoms. Likewise, the longitudinal rigid-shell mode, where sulfur shells vibrate out of phase whilst Mo/W atoms barely move, is predicted to be a fingerprint of the cylindrical configuration in infrared spectra. It is also found that twisting rigid-layer modes characterize chirality of the tubes. Finally, the large diameter limit is discussed and related to the measured Raman and infrared spectra of the layered structures.

New Copper Chalcogenide Clusters with a Selenide Core and a Sulfide Shell

AbstractThe reaction of copper(I) acetate with mixtures of PhSSiMe3 and Se(SiMe3)2 in the presence of PPh3 leads to a series of new cluster compounds consisting of a copper selenide core surrounded by a sulfide shell: [Cu17Se(SPh)15(PPh3)4], [Cu20Se(SPh)12(OAc)6(PPh3)4], [Cu28Se6(SPh)16(PPh3)8], [Cu36Se8(SPh)20(PPh3)8], [Cu54Se8(SPh)30(OAc)8(PPh3)6], and[Cu72Se14(SPh)36(OAc)8(PPh3)6]. They have been structurally characterized by single‐crystal X‐ray analysis. The two smallest clusters have a ball‐like structure with one selenium atom in the center totally enclosed by sulfur atoms. In the other clusters the inner copper–selenium core is surrounded by an incomplete sulfur shell varying between 53 and 87 % coverage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Zeromphonons inMoS2nanotubes

Phonon dispersions of single-wall $\mathrm{Mo}{\mathrm{S}}_{2}$ nanotubes are calculated within a full symmetry implemented valence force-field model. For transversal, twisting, and breathing modes symmetry assignation, chirality, and diameter dependence of their frequencies and displacements are discussed. Tubular structure is found to be characterized by two Raman active modes: by the in-phase breathing mode (in full analogy to carbon nanotubes) with frequency approaching Brillouin scattering domain (as diameter approaches nm), and by the high-energy breathing mode with sulfur shells breathing in phase, but out of phase relative to the molybdenum atoms. Likewise, the longitudinal rigid-shell mode, where sulfur shells vibrate out of phase whilst molybdenum atoms barely move, is predicted to be a fingerprint of the cylindrical configuration in infrared spectra. It is also found that twisting rigid-layer modes characterize chirality of the tubes. Finally, the large diameter limit is discussed and related to the measured Raman and infrared spectra of the layered structure.

Copolymerization of Butyl Vinylsulfonate. Comments on Sulfur Shell Expansion1

Copolymerization of Butyl Vinylsulfonate. Comments on Sulfur Shell Expansion¹