Chemisorption and kinetic mechanisms of elemental mercury on immobilized V2O5/TiO2 at low temperatures

Autor: Chung-Hsuang Hung, Guohua Jing, Chuan-wen Liu, Chung-Shin Yuan, Huazhen Shen
Rok vydání: 2019
Předmět:
Zdroj: Journal of Hazardous Materials. 368:819-829
ISSN: 0304-3894
DOI: 10.1016/j.jhazmat.2019.01.053
Popis: To investigate the effect of low temperature and catalyst filling pattern on the adsorption of Hg° by DeNOx equipment, the chemisorption and kinetic mechanisms of Hg° adsorption on 5–30%V2O5/TiO2 immobilized on glass beads at 100–160 °C were investigated. The effects of the reaction temperature, influent Hg° concentration, and V2O5 doping amount on the adsorption efficiency and capacity for Hg° were explored. The active sites for Hg° adsorption were further identified. Additionally, the adsorption kinetics were modelled using the linear driving force approximation, Fick’s diffusion model, and pseudo-second-order kinetic model. Finally, the influence of immobilization on the adsorption of Hg° was also investigated. Experimental results showed that the bridged oxygen atom of V-O-V played a key role in the adsorption of Hg°. The Hg° adsorption efficiencies decreased from >90% to 40% as the reaction temperature increased from 120 °C to 160 °C for 20%V2O5/TiO2, while the adsorptive capacities for Hg° were highly influenced by the influent Hg° concentration and V2O5 doping amount. 20%V2O5/TiO2 had the highest adsorptive capacity of 2547 μg Hg°/g V2O5/TiO2 at 160 °C. The kinetic results showed that the linear driving force approximation model fit the Hg° adsorption better than the other models. The diffusion resistance increased significantly for the immobilized catalysts because the external mass transfer coefficient decreased by more than 1200-fold.
Databáze: OpenAIRE
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