Evaluation of H-type zeolites in the destructive oxidation of chlorinated volatile organic compounds

González‐Velasco, Juan R.; López‐Fonseca, Rubén; Aranzabal, A.; Gutiérrez-Ortiz, José I.; Steltenpohl, Pavol

doi:10.1016/s0926-3373(99)00105-8

Cited by 120 publications

(58 citation statements)

References 40 publications

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“…The presence of both weak and strong acid sites in Energies 2016, 9, 431 9 of 15 C-ZSM-5 is consistent with the observations reported by Hernández et al [28] and Elordi et al [29]. According to the pyridine chemisorption and infrared spectroscopic studies reported by González-González-Velasco et al [30], the strong acid site, which were identified by NH 3 desorption at a higher temperature in our case, most likely represented the Brønsted acid sites. While B-Zeolite also contained two types of acid sites with a weak acid site concentration (0.215 mmol NH 3¨g´1 comparable to that of C-ZSM-5, its content of strong acid sites was found to be much lower (0.098 mmol NH 3¨g´1 ).…”

Section: Characterization Of Catalystssupporting

confidence: 91%

Investigation into the Catalytic Activity of Microporous and Mesoporous Catalysts in the Pyrolysis of Waste Polyethylene and Polypropylene Mixture

Lee

Yuan

et al. 2016

Energies

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Catalytic pyrolysis behavior of synthesized microporous catalysts (conventional Zeolite Socony Mobil-5 (C-ZSM-5), highly uniform nanocrystalline ZSM-5 (HUN-ZSM-5) and β-zeolite), Mesoporous catalysts (highly hydrothermally stable Al-MCM-41 with accessible void defects (Al-MCM-41(hhs)), Kanemite-derived folded silica (KFS-16B) and well-ordered Al-SBA-15 (Al-SBA-15(wo)) were studied with waste polyethylene (PE) and polypropylene (PP) mixture which are the main constituents in municipal solid waste. All the catalysts were characterized by Brunauer-Emmett-Teller (BET), X-ray powder diffraction (XRD), and NH3-temperature programmed desorption (TPD). The results demonstrated that microporous catalysts exhibited high yields of gas products and high selectivity for aromatics and alkene, whereas the mesoporous catalysts showed high yields of liquid products with considerable amounts of aliphatic compounds. The differences between the microporous and mesoporous catalysts could be attributed to their characteristic acidic and textural properties. A significant amount of C2-C4 gases were produced from both types of catalysts. The composition of the liquid and gas products from catalytic pyrolysis is similar to petroleum-derived fuels. In other words, products of catalytic pyrolysis of plastic waste can be potential alternatives to the petroleum-derived fuels.

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Section: Characterization Of Catalystssupporting

confidence: 91%

Investigation into the Catalytic Activity of Microporous and Mesoporous Catalysts in the Pyrolysis of Waste Polyethylene and Polypropylene Mixture

Lee

Yuan

et al. 2016

Energies

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“…According to the results obtained from the acidity characterisation, strong Brønsted acidity appears to play a dominant role in determining the catalytic behaviour of H-type zeolites. 21 It is well accepted in the literature that the oxidation of chlorinated hydrocarbons is initiated by the adsorption on Brønsted sites. 4,22,23 The main oxidation products in the decomposition of these chlorinated compounds were carbon monoxide, carbon dioxide, hydrogen chloride and chlorine.…”

Section: Catalytic Activity Resultsmentioning

confidence: 99%

Catalytic combustion of chlorinated ethylenes over H‐zeolites

López‐Fonseca

Gutiérrez-Ortiz

et al. 2002

J of Chemical Tech & Biotech

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Several H-zeolites (H-Y, H-ZSM-5 and H-MOR) were investigated for the catalytic combustion of chlorinated ethylenes, namely 1,1-dichloroethylene and trichloroethylene. Conversion was inversely related to the chlorine content of the feed molecule. H-ZSM-5 zeolite was the most active catalyst in 1,1-dichloroethylene combustion whereas H-MOR was the most effective zeolite for trichloroethylene destruction. Temperature-programmed desorption of ammonia and diffuse reflectance FT-IR measurements of adsorbed pyridine revealed that strong Brønsted acidity plays an important role in controlling the activity of H-zeolites. The main combustion products were CO, CO 2 , HCl, and Cl 2 . Additionally, small amounts of highly chlorinated by-products were also detected, namely trichloroethylene and tetrachloroethylene. H-zeolites showed a great selectivity to HCl formation.

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“…At lower temperatures the hydrogen needed to form HCl comes mainly from the TCE feed molecule, however, at higher temperatures the amount of hydrogen present in the feed is not enough to convert all chlorine atoms into HCl. Thus, other sources of hydrogen as water impurities in the feed stream [59] and even hydrogen from the Brönsted sites of the catalyst may be responsible of this effect. When TCE starts to decompose, no Cl 2 is detected at low temperatures, probably because it reacts with TCE to form tetrachloroethylene (C 2 Cl 4 ).…”

Section: Selectivitymentioning

confidence: 99%