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The adsorption of sulfur dioxide (SO 2 ) on pristine and modified graphyne (including boron- or nitrogen- doping and introducing a single carbon atom defect) was investigated by density functional theory calculations. The structural, electronic, and magnetic properties of graphyne were changed according to the dopant atom site of doping and vacancy. SO 2 adsorption was obviously affected by modification of graphyne. SO 2 weakly interacted with pristine and nitrogen-doped graphynes. Boron doping at the sp-hybridized carbon site and introducing a single carbon atom vacancy in graphyne brought about a dramatic enhancement in SO 2 adsorption. The strongly chemisorbed SO 2 at these active sites caused deformation of the graphyne structure and electron redistribution, which induced changes in the conductivity and magnetism of graphynes. [ABSTRACT FROM AUTHOR]

B 4 C 12 achieves a rapid and stable CO 2 adsorption with a novel η3(O, C, O)-CO 2 configuration, and a small limiting potential for CO2RR producing HCOOH associating with suppressed HER. [Display omitted] The electrochemical reduction of CO 2 (CO2RR) to formic acid (HCOOH) is a promising approach to harness renewable energy for the production of value-added chemicals and contribute to carbon cycling. The search for cost-effective and efficient metal-free electrocatalysts is critical for realizing industrial applications. However, limited literature is available on this topic, primarily because the significant challenge of efficiently activating inert CO 2 remains unresolved. In this study, we have designed and applied a novel boron carbide (B 4 C 12) monolayered cage as an electrocatalyst for CO2RR to produce HCOOH. B 4 C 12 exhibits exceptional electronic, dynamic, and thermodynamic stability. Through comprehensive density functional theory computations, we have observed that B 4 C 12 rapidly and stably adsorbs CO 2 in a unique η3(O, C, O)-CO 2 configuration, resulting in excellent CO2RR activity with a low limiting potential (–0.38 V) and suppressed hydrogen evolution reaction. Our mechanistic investigations reveal that B 4 C 12 donates electrons to facilitate the bending of CO 2 , anchoring it onto the curved surface effectively. Additionally, the C atom in the η3(O, C, O)-CO 2 configuration attracts H+ + e− pairs through its active p electron, leading to the observed low limiting potential. This study not only successfully designs a novel class of metal-free electrocatalysts but also provides a promising strategy for advancing CO2RR research in the future. [ABSTRACT FROM AUTHOR]

Vanadium (V) and tungsten (W) are essential metals for various industries, but separating them is challenging due to the molecular similarity of the two metal ions. A highly concentrated mixed solution of V and W is obtained from spent selective catalytic reduction (SCR) catalysts, but their complete recycling is impeded by the difficulty of separating V and W. In this study, we investigate the ion exchange resin (IXR) technique's effectiveness for separating V and W from the leaching solution of spent catalysts. We evaluated the performance of three IXRs: Lewatit MP800 (strong basic), MP62WS (medium basic), and TP260 (weak acidic) for the separation of V and W ions in the solution. Among these IXRs, MP800 exhibits V and W ion separation behavior at pH 14. It selectively adsorbs W ions, while V ions demonstrate low affinity for adsorption on MP800. The primary mechanism for the adsorption of V and W ions appears to be an ion exchange reaction on the quaternary ammonium group of MP800. Conversely, MP62WS, which adsorbs V and W ions through both ion exchange and chelation mechanisms, does not separate V and W ions effectively when the solution's pH is controlled. The adsorbed W ions on MP800 can be completely regenerated with 2 M NaCl solution through re-ion exchange. We also conducted dynamic column operations using a simulated spent catalyst leaching solution (V = 600 mg/L, W = 4000 mg/L) with MP800 at pH 14. The successful separation of V and W was achieved for up to 15 bed volumes (BV). Finally, we performed V and W separation using an actual spent catalyst leaching solution. MP800 displayed a notably high separation factor (α V W) of 19.59, highlighting its effectiveness in separating V and W. [Display omitted] • The separation of vanadium(V) and tungsten(W) was investigated by ion exchange technique. • The W ion is selectively adsorbed onto Lewatit MP800 at pH 14 but V ion remains in leachate. • The adsorption of V or W ions on MP800 at pH 14 is based on an ion exchange mechanism. • V and W can be completely separated from each other in a continuous column operation. • In an actual SCR leachate, MP800(pH 14) demonstrates the feasibility of separating W. [ABSTRACT FROM AUTHOR]

Abstract: The adsorption of pyridine onto the metal organic framework MIL-101 was investigated by experimental and theoretical methods. The amount of pyridine adsorbed on MIL-101 was extraordinarily large at 20°C, corresponding to about 950mg/g of dried MIL-101 and approximately half of the voids being filled. Most of the pyridine that had filled the voids was rapidly removed by evacuation at room temperature, but some of the pyridine was so strongly adsorbed that it was retained even under evacuation at 150°C. Although IR spectra of the adsorbed pyridine indicated the adsorption of pyridine as pyridinium ions and coordinated pyridine at low temperatures, increasing the adsorption temperature induced partial cleavage of the pyridine rings. The high stabilization energy of pyridine on the coordinative unsaturated sites (CUS) of MIL-101, obtained by theoretical calculation, −103kJ/mol, supported the strong adsorption of pyridine on the CUS. [Copyright &y& Elsevier]