A Novel Porous Ceramic Membrane Supported Monolithic Cu-Doped Mn–Ce Catalysts for Benzene Combustion

Abstract

Porous ceramic membranes (PCMs) are considered as an efficient hot gas filtration material in industrial systems. Functionalization of the PCMs with high-efficiency catalysts for the abatement of volatile organic compounds (VOCs) during dust elimination is a promising way to purify the industrial exhaust gases. In this work, we prepared PCMs (porosity: 70%) in a facile sintering process and integrated Cu-doped Mn-Ce oxides into the PCMs as monolithic catalysts by the sol-gel method for benzene oxidation. Through this method, the catalysts are dispersed evenly throughout the PCMs with excellent adhesion, and the catalytic PCMs provided more active sites for the reactant gases during the catalytic reaction process compared to the powder catalysts. The physicochemical properties of PCMs and catalytic PCMs were characterized systematically, and the catalytic activities were measured in total oxidation of benzene. As a result, all the prepared catalytic PCMs exhibited high catalytic activity for benzene oxidation. Significantly, the monolithic catalyst of Cu 0.2 Mn 0.6 Ce 0.2 /PCMs obtained the lowest temperature for benzene conversion efficiency of 90% (T 90 ) at 212 • C with a high gaseous hourly space velocity of 5000 h −1 and showed strong resistance to high humidity (90 vol.%, 20 • C) with long-term stability in continuous benzene stream, which is caused by abundant active adsorbed oxygen, more surficial oxygen vacancy, and lower-temperature reducibility.higher conversion efficiency at lower temperature [13][14][15][16]. A successful catalyst used for industrial applications usually requires high activity, stability, heat resistance, and low pressure drop during long-term operation for high airflow gaseous catalytic combustion. Therefore, a monolithic catalyst by functionalizing the PCMs with catalytic active ingredients is much necessary for the removal of VOCs during dedusting for air pollution control in the industrial application.Currently, the transition metal oxide catalysts, by considering economical and effective elements, are better alternatives in contrast to the noble metal catalysts [17,18]. Among all the transition metals, the synergistic effect of Mn and Ce mixed oxides exhibited enhanced catalytic activity during benzene oxidation [19][20][21][22][23] that generally attributed to the abundance, low cost, numerous oxidation states, and high poison-resistance of manganese oxides [24,25], and the super oxygen storage capacity of ceria oxides which are regarded as viable segments in the VOCs oxidation [26,27]. Moreover, to further improve physiochemical properties, the ternary metal oxides catalysts (e.g., Mn-Ce-Co [28,29], Mn-Ce-Zr [30], Mn-Ce-Cu [31-33],) are popularly used in the field of VOCs removal. Such series of catalysts exhibit higher catalytic activity than binary and single metal oxides and show excellent stability and water vapor resistance properties during a long-term reaction due to the synergistic effects. The ionic radius of Cu is between the ionic radius of Mn and Ce, so the Cu ions ...

Study on the Adsorption Properties of Oxalic Acid-Modified Cordierite Honeycomb Ceramics for Neutral Red Dyes

“… 34 − 37 For instance, porous ceramic membranes (PCMs), which are monolithic catalysts, have many applications in mass and heat transfer, and PCMs offered more active sites for the reactant gases during the catalytic reaction process than the powder catalysts did. 38 In one study, the monolithic catalysts of diatomite-modified wood ceramics have been widely used for the adsorption of pollutants due to their large specific surface area, strong adsorption capacity, and lower cost. 39 …”

“…34−37 For instance, porous ceramic membranes (PCMs), which are monolithic catalysts, have many applications in mass and heat transfer, and PCMs offered more active sites for the reactant gases during the catalytic reaction process than the powder catalysts did. 38 In one study, the monolithic catalysts of diatomite-modified wood ceramics have been widely used for the adsorption of pollutants due to their large specific surface area, strong adsorption capacity, and lower cost. 39 Compared to conventional pellets or powder catalysts, which have the drawbacks of a low recycling rate and difficult recovery in an aqueous solution, cordierite honeycomb ceramics (COR), which have a high specific surface area, 40 high permeability, high adsorption capacity, relatively high mechanical strength, 41,42 inherent high porosity, 43 and low cost, were chosen as adsorbents.…”

“…Additionally, these adsorbents are challenging to recover and are not conducive to reuse or recycle. The monolithic adsorbent has proven to be a practical and affordable way to remove a variety of pollutants in some research. − For instance, porous ceramic membranes (PCMs), which are monolithic catalysts, have many applications in mass and heat transfer, and PCMs offered more active sites for the reactant gases during the catalytic reaction process than the powder catalysts did . In one study, the monolithic catalysts of diatomite-modified wood ceramics have been widely used for the adsorption of pollutants due to their large specific surface area, strong adsorption capacity, and lower cost …”

Effect of the Properties of Cordierite Support and Catalyst Slurry on the Catalytic Degradation of Toluene by Monolith Catalyst

“…In the current VOCs removal process, catalytic combustion is one of the more mature and widely used technologies, which transforms VOCs into pollution-free substances at low temperature through the action of catalyst [2] . In practical industrial applications, monolithic catalysts are widely used because of their lower bed pressure [3] , better interphase mass transfer [4] and heat transfer performance [5] compared with powder catalysts. At present, honeycomb ceramics is commonly used as the carrier of integral catalyst, which has the advantages of regular shape and high mechanical strength [6] .…”

Editorial Catalysts: Catalysis for the Removal of Gas-Phase Pollutants

“…These materials presented high-valence cobalt ions in the catalyst surface due to the hierarchical nanostructures as well as adsorbed oxygen species and abundant medium-strength surface acid sites that played a key role in catalytic activity. The same author proposed the use of Cu-doped Mn/Ce catalysts supported on a novel porous ceramic membrane monolith for benzene combustion [8]. Porous ceramic membranes (PCMs) are considered to be an efficient hot gas filtration material in industrial systems.…”