نتایج جستجو برای: sulfides
تعداد نتایج: 8971 فیلتر نتایج به سال:
Porous nanostructured materials are demonstrated to be very promising in catalysis due to their well accessible active sites. Thermally stable metal-organic frameworks (MOFs) as hard templates are successfully utilized to afford porous metal oxides and subsequently metal sulfides by a nanocasting method. The resultant metal oxides/sulfides show considerable Brunauer-Emmett-Teller (BET) surface ...
3-Sulfanyl-oxetanes are presented as promising novel bioisosteric replacements for thioesters or benzyl sulfides. From oxetan-3-ols, a mild and inexpensive Li catalyst enables chemoselective C-OH activation and thiol alkylation. Oxetane sulfides are formed from various thiols providing novel motifs in new chemical space and specifically as bioisosteres for thioesters due to their similar shape ...
The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide ran...
There were similar distribution characteristics for acid volatile sulfides (AVS) and simultaneously extracted metals (SEM) in surface sediments, and the concentrations of AVS and SEM decreased from the deposition area to the center of the bay (lake). The ratio of AVS to SEM was <1 in the surface sediments, indicating that heavy metals in surface sediments may be bioavailable. The concentration ...
Biogeochemical reductive dechlorination (BiRD) is a new remediation approach for chlorinated aliphatic hydrocarbons (CAHs). The approach stimulates common sulfate-reducing soil bacteria, facilitating the geochemical conversion of native iron minerals into iron sulfides. Iron sulfides have the ability to chemically reduce many common CAH compounds including PCE, TCE, DCE, similar to zero valent ...
The increasing use of silver (Ag) nanoparticles [containing either elemental Ag (Ag-NPs) or AgCl (AgCl-NPs)] in commercial products such as textiles will most likely result in these materials reaching wastewater treatment plants. Previous studies indicate that a conversion of Ag-NPs to Ag2S is to be expected during wastewater transport/treatment. However, the influence of surface functionality,...
Three types of copper sulfides including CuS, Cu7S4 and Cu9S5 were successfully synthesized at different concentrations of ethylenediamine in a liquid phase synthesis process. The whole shape evolution of Cu7S4 microstructures could be manipulated by adjusting the concentration of ethylenediamine. This study indicates that the coordination chemistry of ethylenediamine ligands and copper cations...
For the first time, dioxomolybdenum(VI) complex with the general formula [MoO2L2] containing a N-O bidentate ligands (HL=2-(o-aminophenyl)- benzimidazole) has been used for the oxidation of sulfides. Elemental analyses (carbon, hydrogen, nitrogen), FT-IR and Uv-Visble spectra and 1HNMR analysis agree well with the proposed stoicheiometry of the complex [MoO...
Cretaceous kimberlites in southern Africa have been suggested to host deeply subducted material their mantle sources based on radiogenic isotope systematics. However, potential contributions the volatile budget, including sulfur, of these is unclear. Here we report new petrographic, geochemical, and isotopic data sulfides sulfates sub-volcanic from Kimberley, South Africa. The examined were div...
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