In situ adsorption-catalysis system for the removal of o-xylene over an activated carbon supported Pd catalyst

Abstract

An activated carbon (AC) supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene. In this study, three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal. The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature. After saturated adsorption, the adsorbed o-xylene was oxidized to CO 2 and H 2 O by raising the temperature of the catalyst bed. The results showed that more than 99% of the adsorbed o-xylene was completely oxidized to CO 2 over a 5% Pd/AC catalyst at 140°C. Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), temperatureprogrammed desorption (TPD), and temperature-programmed oxidation (TPO) were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst. A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.

Synthesis and physicochemical characterization of nanostructured Pd/ceria‐clinoptilolite catalyst used for p‐xylene abatement from waste gas streams at low temperature

“…10(b) shows a minor weight-loss step as the CeO 2 is added to modified zeolite, indicating that it is slightly hydrated. This mass loss corresponds to the decomposition of Ce(OH) 3 or Ce(OH) 4 /CeO 2 .2H 2 O. Almost no weight loss is observed above 400 • C, suggesting the formation of crystalline CeO 2 as a decomposition product.…”

“…Volatile organic compounds (VOCs) are a major category of air pollutants, contributing to the formation of photochemical smog and destruction of the ozone layer. BTX (benzene, toluene, xylene), as major VOCs, are of particular concern due to their high toxic potential for human beings . There are many different techniques available to remove VOCs from polluted air.…”

Recent Development of Catalysts for Removal of Volatile Organic Compounds in Flue Gas by Combustion: A Review

“…The same as for Pt based catalysts, cation exchange process was also recommended for the preparation of Pd based catalysts [31,32,37] as this methodology allows the introduction of the active phase inside the support structure instead of having a simple deposition on the support surface. Deposition-precipitation, wet or dry impregnation methods were also used to prepare this type of catalysts [20,33,35,38].…”

“…Different supports were tested as it can be expected that differences in morphology and surface area can influence the catalytic activity [20,31,32]. Especially for the various forms of active carbon it can be noticed that physical and chemical properties of the support influence the metal deposition, dispersion, and the gas adsorption efficiency of the support [20,35]. It has been recently reported that active compounds such as titania (TiO 2 ) or Ni nanofibers doped with metals have been investigated [33,34].…”

“…The development of different types of catalysts for catalytic combustion of VOCs has been widely reported in the literature [19][20][21][22]. The review paper published in 2004 by Everaert and Baeyens presents a good overview of catalytic combustion of VOCs on theoretical combustion kinetics, performance of various classes of catalysts, and different reactor geometries [19].…”