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The detection of the identities and concentrations of sulfur hexafluoride, SF 6 , decomposition products is important for evaluating the conditions of SF 6 -gas-insulated equipment. This study is a preliminary test of the use of cassiterite (110) for detecting SF 6 and SF 6 decomposition gases, including HF, H 2 S, SO 2 , SOF 2 , SO 2 F 2 , CF 4 , CO, and CO 2 . First-principles calculations were adopted to investigate the adsorption mechanism of SF 6 decomposition gases on a cassiterite (110) surface, using adsorption energy, geometrical structure, frontier molecular orbitals, electron density, density of states, potential energy, and work functions. We found that the adsorption of H 2 S made a noticeable change in the electronic properties of the (110) surface. The adsorption of SO 2 strongly influenced the charge distribution of the cassiterite (110) surface and made the greatest decrease in the work function of the nine gas molecules tested. Conversely, changes in the cassiterite's electronic properties induced by other gases, especially SF 6 , were slight. Therefore, cassiterite could be a promising candidate for highly selective and sensitive sensors to detect H 2 S and SO 2 in SF 6 decomposition gases. [ABSTRACT FROM AUTHOR]

Abstract: An anion-imprinted material with high performance for recognizing chromate anion was prepared by adopting the novel molecule surface-imprinting technique put forward by our research group previously. Functional macromolecule polyvinylimidazole (PVI) was first grafted on the surfaces of micron-sized silica gel particles, forming the grafted particle PVI/SiO2. Afterwards, the ion imprinting was carried out towards the grafted macromolecule PVI by using anion as template and 1,6-dibromohexane as crosslinking agent, and chromate ion surface-imprinted material IIP-PVI/SiO2 was obtained. The binding characteristic of IIP-PVI/SiO2 towards anion was studied with both static and dynamic methods. The experimental results show that IIP-PVI/SiO2 has excellent binding affinity and high recognition selectivity for chromate anion. Before imprinting, the grafted particles PVI/SiO2 have similar adsorption capacities for both two anions, chromate anion and phosphate anion that was used as a contrast anion. However, after imprinting, the binding capacity of IIP-PVI/SiO2 towards phosphate anion decreases remarkably, whereas the binding capacity of IIP-PVI/SiO2 for chromate anion still remains very high, leading to a high selectivity coefficient (7.78) of IIP-PVI/SiO2 for anion with respect of ion. [Copyright &y& Elsevier]