Special Issue "Catalytic Treatment of Air Pollutants (VOCs, PACs, PCDDs/PCDFs, Soot, NOx, CO)"

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Environmental Catalysis".

Deadline for manuscript submissions: 20 January 2022.

Special Issue Editors

Dr. Fan Lin
E-Mail Website
Guest Editor
Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, WA 99352, USA
Interests: heterogeneous catalysis; biomass conversion; emission control; soot oxidation; HC oxidation; DeNOx
Prof. Dr. Jong-Ki Jeon
E-Mail Website
Guest Editor
Department of Chemical Engineering, Kongju National University, Cheonan 31080, Korea
Interests: Environmental catalysis; NOx; Air Pollutants; VOCs; CO

Special Issue Information

Dear Colleagues,

The preservation of clean air demands detailed scientific research taking into consideration practical conditions. To enhance sustainability, emissions reduction measures focused on the air pollutants (volatile organic compounds (VOCs), polyaromatic compounds (PACs), polychlorinated dioxins and furans (PCDDs/PCDFs), CO, NOx, and soot particles) need, thus, to be researched under practical conditions. These pollutants can be substantially reduced by catalytic exhaust systems and integrated methods.

This Special Issue aims to collect original research papers, reviews, and commentaries focused on the challenges for the catalytic treatment of air pollutants. Submissions are welcome especially (but not exclusively) in the following areas:

- catalytic treatment of VOCs;
- catalytic treatment of CO;
- catalytic treatment of NOx;
- catalytic treatment of Soot;
- catalytic treatment of PACs;
- catalytic treatment of PCDDs/PCDFs;
- innovative processes and reactors for catalytic treatment of air pollutants.

Dr. Lin Fan
Prof. Jong-Ki Jeon
Guest Editor

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • environmental catalysis
  • air pollutants
  • NOx
  • VOCs
  • CO

Published Papers (6 papers)

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Research

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Open AccessArticle
Properties of Iron-Modified-by-Silver Supported on Mordenite as Catalysts for NOx Reduction
Catalysts 2020, 10(10), 1156; https://doi.org/10.3390/catal10101156 - 09 Oct 2020
Cited by 1 | Viewed by 636
Abstract
A series of mono and bimetallic catalysts based on a Fe-Ag mixture deposited on mordenite was prepared by ion-exchange and evaluated in the catalytic activity test of the de-NOx reaction in the presence of CO/C3H6. The activity results showed [...] Read more.
A series of mono and bimetallic catalysts based on a Fe-Ag mixture deposited on mordenite was prepared by ion-exchange and evaluated in the catalytic activity test of the de-NOx reaction in the presence of CO/C3H6. The activity results showed that the most active samples were the Fe-containing ones, and at high temperatures, a co-promoter effect of Ag on the activity of Fe catalysts was also observed. The influence of the order of cation deposition on catalysts formation and their physicochemical properties was studied by FTIR (Fourier Transform Infrared Spectroscopy) of adsorbed NO, XANES (X-ray Absorption Near-Edge Structure), and EXAFS (Extended X-ray Absorption Fine Structure) and discussed in terms of the state of iron. Results of Fe K-edge XANES oscillations showed that, in FeMOR catalysts, iron was present in a disordered state as Fe3+ and Fe2+. In FeAgMOR, the prevailing species was Fe3+, while in the AgFeMOR catalyst, the state of iron was intermediate or mixed between FeMOR and FeAgMOR. The Fe K-edge EXAFS results were characteristic of a disordered phase, the first coordination sphere being asymmetric with two different Fe-O distances. In FeAgMOR and AgFeMOR, coordination of Fe-O was similar to Fe2O3 with a few amount of Fe2+ species. We may conclude that, in the bimetallic FeAgMOR and AgFeMOR samples, a certain amount of tetrahedral Al3+ ions in the mordenite framework is replaced by Fe3+ ions, confirming the previous reports that these species are active sites for the de-NOx reaction. Based on the thermodynamic analysis and experimental data, also, it was confirmed that the order of deposition of the components influenced the mechanism of active sites’ formation during the two steps ion-exchange synthesis. Full article
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Open AccessArticle
Particle Number Emissions of a Diesel Vehicle during and between Regeneration Events
Catalysts 2020, 10(5), 587; https://doi.org/10.3390/catal10050587 - 23 May 2020
Cited by 9 | Viewed by 919
Abstract
All modern diesel vehicles in Europe are equipped with diesel particulate filters (DPFs) and their particle number (PN) emissions at the tailpipe are close to ambient air levels. After the Dieselgate scandal for high NOx emissions of diesel vehicles on the road, [...] Read more.
All modern diesel vehicles in Europe are equipped with diesel particulate filters (DPFs) and their particle number (PN) emissions at the tailpipe are close to ambient air levels. After the Dieselgate scandal for high NOx emissions of diesel vehicles on the road, the high PN emissions during regeneration events are on the focus. The PN emissions of a diesel vehicle on the road and in the laboratory with or without regeneration events were measured using systems with evaporation tubes and catalytic strippers and counters with lower sizes of 23, 10 and 4 nm. The tests showed significant PN levels only during engine cold starts with a big fraction of sub-23 nm particles during the first minute. After the first seconds the sub-23 nm fraction was negligible. Urea injection at the selective catalytic reduction (SCR) for NOx system did not affect the PN levels and the sub-23 nm fraction. The emissions during regeneration events were higher than the PN limit, but rapidly decreased 2-3 orders of magnitude below the limit after the regeneration. Artificially high sub-10 nm levels were seen during the regeneration (volatile artifact) at the system with the evaporation tube. The regenerations were forced every 100–350 km and the overall emissions including the regeneration events were two to four times lower than the current laboratory PN limit. The results of this study confirmed the efficiency of DPFs under laboratory and on-road driving conditions. Full article
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Open AccessArticle
Enhanced Catalytic Performance of Hierarchical MnOx/ZSM-5 Catalyst for the Low-Temperature NH3-SCR
Catalysts 2020, 10(3), 311; https://doi.org/10.3390/catal10030311 - 09 Mar 2020
Cited by 5 | Viewed by 739
Abstract
A ZSM-5 zeolite with a hierarchical pore structure was synthesized by the desilication-recrystallization method using tetraethyl ammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) as the desilication and structure-directing agents, respectively. The MnOx/ZSM-5 catalyst was synthesized by the ethanol dispersion method and [...] Read more.
A ZSM-5 zeolite with a hierarchical pore structure was synthesized by the desilication-recrystallization method using tetraethyl ammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) as the desilication and structure-directing agents, respectively. The MnOx/ZSM-5 catalyst was synthesized by the ethanol dispersion method and applied for the low-temperature selective catalytic reduction of NOx with NH3. The results showed that NOx conversion of the hierarchical MnOx/ZSM-5 catalyst could reach 100% at about 120 °C and could be maintained in the temperature range of 120–240 °C with N2 selectivity over 90%. Furthermore, the hierarchical MnOx/ZSM-5catalyst presented better SO2 resistance performance than the traditional catalyst in the presence of 100 ppm SO2 at 120 °C. XRD, SEM, TEM, XPS, BET, NH3-TPD, and TG were applied to characterize the structural properties of the MnOx/ZSM-5 catalysts. These results showed that the MnOx/ZSM-5 catalyst had micropores (0.78 nm) and mesopores (3.2 nm) leading to a larger specific surface area, which improved the mass transfer of reactants and products while reducing the formation of sulfates. The better catalytic performance over hierarchical MnOx/ZSM-5 catalyst could be attributed to the higher concentration of Mn4+ and chemisorbed oxygen species and higher surface acidity. The improved SO2 resistance was related to the catalyst’s hierarchical pore structure. Full article
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Open AccessArticle
Nanosized V-Ce Oxides Supported on TiO2 as a Superior Catalyst for the Selective Catalytic Reduction of NO
Catalysts 2020, 10(2), 202; https://doi.org/10.3390/catal10020202 - 07 Feb 2020
Viewed by 599
Abstract
Nanosized V-Ce oxides supported on TiO2 (VCT) were prepared and utilized in the low-temperature selective catalytic reduction (SCR) of NO with NH3. Compared with the other V-Ce oxides-based catalysts supported on Al2O3, ZrO2, and [...] Read more.
Nanosized V-Ce oxides supported on TiO2 (VCT) were prepared and utilized in the low-temperature selective catalytic reduction (SCR) of NO with NH3. Compared with the other V-Ce oxides-based catalysts supported on Al2O3, ZrO2, and ZSM-5, VCT showed the best SCR activity in a low-temperature range. The NOx conversion of 90% could be achieved at 220 °C. Characterizations including X-ray diffraction (XRD), scanning election micrograph (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption with NH3 (NH3-TPD), and temperature-programmed reduction with H2 (H2-TPR) showed that V1.05Ce1/TiO2 exhibited a good dispersion of V2O5, enrichment of surface Ce3+ and chemical-absorbed oxygen, and excellent redox capacity and acidity, which resulted in the best SCR performance at low temperature. Full article
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Open AccessArticle
In Situ IR Study on Effect of Alkyl Chain Length between Amines on Its Stability against Acidic Gases
Catalysts 2019, 9(11), 910; https://doi.org/10.3390/catal9110910 - 30 Oct 2019
Cited by 3 | Viewed by 929
Abstract
For the CO2 capture process via the cyclic adsorption/desorption method, one emerging catalyst is the use of amine-functionalized silica. This study focused on comparing the CO2 capture performance of diamines with ethyl and propyl spacers and the degradation species formed after [...] Read more.
For the CO2 capture process via the cyclic adsorption/desorption method, one emerging catalyst is the use of amine-functionalized silica. This study focused on comparing the CO2 capture performance of diamines with ethyl and propyl spacers and the degradation species formed after long-term exposure to various acidic gases such as SO2 and NO2 at elevated temperatures. Adsorbents were prepared via the incipient wetness technique and then subjected to thermogravimetric measurements and in situ FT-IR analyses. 2NS-P/Kona95, which contains a propyl spacer, showed fewer degradation species formed based on its IR spectra and better stability with its long-term exposure to various acidic gases. Thus, the incorporation of amines with a large number of nitrogen groups of propyl or longer spacer length could be a promising CO2 capture material. Full article
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Review

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Open AccessReview
A Critical Review of Recent Progress and Perspective in Practical Denitration Application
Catalysts 2019, 9(9), 771; https://doi.org/10.3390/catal9090771 - 13 Sep 2019
Cited by 10 | Viewed by 1620
Abstract
Nitrogen oxides (NOx) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of [...] Read more.
Nitrogen oxides (NOx) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NOx, it is urgent to control NOx. According to the different mechanisms of NOx removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NOx. At the same time, the current research status and existing problems of different NOx removal technologies were revealed and the future development prospects were forecasted. Full article
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Removal of NOx by the combination of non-thermal plasma and zeolites: A review     

Moazameh Adhami Sayad Mahaleh, Savita Kaliya Perumal Veerapandian, Rim Bitar, Rino Morent, Nathalie De Geyter

Research Unit Plasma Technology, Department of Applied Physics, Ghent University, Belgium

Abstract: The combination of non-thermal plasma and different types of zeolite based-catalysts as an alternative technology for the removal of oxides of nitrogen (NOx) is reviewed in this work. NOx are the main toxic by-products from the engine exhausts. Various factors which play a major role in the enhancement of deNOx efficiency such as the properties of exhaust gas (temperature, presence of hydrocarbon, oxygen and water vapor), the used catalysts (type and amount of metal loading) and the applied non-thermal plasma discharge (type, electrical parameter) will be discussed.

In recent years, zeolite based-catalyst have been widely studied in the field of NOx reduction and have attracted significant attention due to their high NO reduction efficiencies as a result of their promising activity and selectivity in various temperature ranges. Among different catalysts, zeolites are known as low cost, durable catalysts and are active in de-NOx reactions, both in NOx decomposition and selective catalytic reduction (SCR) by hydrocarbons. The high density and strength of their Bronsted sites make these catalysts also very active for the reaction steps in HC-SCR. Since nonthermal plasma is able to provide oxygenate species, nitrogen-containing organic species, and to convert NO to NO2, the zeolite-plasma combination system shows excellent synergy for NOx removal and will therefore be thoroughly described in this review paper.

 Keywords:

NOx removal, zeolites, non-thermal plasma, plasma catalysis. 

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