Comparative evaluation of synthesis routes of Cu/zeolite Y catalysts for catalytic wet peroxide oxidation of quinoline in fixed-bed reactor. (1st June 2018)

• Record Type: Journal Article
• Authors: Singh, Lovjeet; Rekha, Pawan; Chand, Shri
• Is Part Of: Journal of environmental management. Volume 215(2018)
• Page Start: 1
• Page End: 12
• Publication Date: 2018-06-01
• Subjects: Synthesis routes -- Cu/zeolite Y -- Continuous catalytic wet peroxide oxidation -- Quinoline -- Reaction mechanism; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2018.03.021
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: In order to find a better alternative of conventional aqueous ion-exchange method, several Cu/zeolite Y samples were synthesized by different routes and examined for the catalytic wet peroxide oxidation of quinoline aqueous solution in continuous fixed-bed reactor. The characterization of catalysts using ICPMS, XRD, N2 sorption, UV–vis DRS, FESEM and XPS techniques reveals the profound influence of preparation methods on synergy between copper-support interfaces. Aqueous ion-exchange (CuYAIE ) and wet-impregnation (CuYIMP ) methods promoted isolated Cu 1+/2+ species; however, large crystallites of CuO were present on the external surface of precipitation-impregnation (CuYPI ) catalyst. Interestingly, CuYPI showed hierarchical porosity and increase of surface area from 567 to 909 m 2 g −1 . The generation of mesoporosity in CuYPI was result of higher desilication from zeolite framework due to synergetic effect of copper and NaOH. Almost comparable mineralization (61–65%) and H2 O2 stoichiometric efficiencies (44.2–45.7%) were observed for CuYAIE and CuYIMP samples. Higher catalytic activities of both catalysts in comparison to CuYPI suggest that isolated sites are the most redox-active sites for H2 O2 activation and play more important role than high surface area, i.e., for CuYPI . Wet-impregnation was found better than aqueous ion-exchange method. CuYIMP exhibited high operation stability with >60% mineralization at LHSV = 4 h −1, particle size = 1.2–1.7 mm, H2 O2 /quinoline = 48 and T = 80 °C. Copper leaching was majorly influenced by LHSV and particle size. The system was following Eley-Rideal mechanism and kinetic parameters were calculated using model based on this mechanism. Graphical abstract: Image 1 Highlights: Preparation methods affects structure, texture and coordination environment of CuY. AIE and IMP methods facilitate isolated copper species. PI method induces hierarchical porosity and increases SLang from 567 to 909 m 2 g −1 . Isolated species show higher activity in comparison to CuO crystallites. IMP method has been found a better alternative to AIE.