Catalytic Purification of Pollutants and Catalytic Conversion of Solid Wastes

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

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 26636

Special Issue Editors


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Guest Editor
School of Chemical Engineering & Technology, Hebei University of Technology, Tianjin 300130, China
Interests: solid waste; NOx reduction; petroleum engineering; catalyst characterization; SCR
Special Issues, Collections and Topics in MDPI journals
School of Chemical Engineering & Technology, Hebei University of Technology, Tianjin, China
Interests: removal of multiple pollutants; AOPs; photocatalysis; recycling of biomass/spent Li-ion batteries
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Thank you for your interest in publishing your work in Catalysts. This Special Issue invites contributions of original high-quality interdisciplinary research papers devoted to currently important topics in catalysis and related subjects. Studies significantly advancing our fundamental understanding of and focusing on the Catalytic Purification of Pollutants and Catalytic Conversion of Solid Wastes will be given primary consideration. Field studies have preference, while papers describing laboratory experiments must demonstrate significant advances in methodology or mechanistic understanding with a clear connection to the catalytic pathway and catalysis chemistry. Descriptive, repetitive, incremental, or regional-scale studies with limited novelty will not be considered.

Prof. Dr. Boxiong Shen
Dr. Peng Yuan
Guest Editors

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Keywords

  • DeNOx by SCR/AOPs
  • Photocatalytic oxidation/degradation of gaseous pollutants (Hg0, VOCs, etc.)
  • Catalytic pyrolysis of solid wastes (biomass, plastics, textiles, etc.)
  • Novel and commercially applicable environmental catalysts (deactivation, modification, regeneration, etc.)
  • New catalytic processes for the production of clean energy (syngas, oil, etc.)
  • New catalytic combustion technologies and catalysts
  • Efficient capture and catalytic conversion of CO2
  • Critical reviews on current or emerging topics in environmental catalysis.

Published Papers (13 papers)

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Research

Jump to: Review

15 pages, 3206 KiB  
Article
The Catalytic Performance of CO Oxidation over MnOx-ZrO2 Catalysts: The Role of Synthetic Routes
by Olga A. Bulavchenko, Valeriya P. Konovalova, Andrey A. Saraev, Anna M. Kremneva, Vladimir A. Rogov, Evgeny Yu. Gerasimov and Tatyana N. Afonasenko
Catalysts 2023, 13(1), 57; https://doi.org/10.3390/catal13010057 - 27 Dec 2022
Cited by 6 | Viewed by 1488
Abstract
MnOx-ZrO2 catalysts prepared by co-precipitation and vacuum impregnation were calcined at 400–800 °C and characterized by powder X-ray diffraction, textural studies, high-resolution transmission electron microscopy, temperature-programmed reduction, X-ray absorption near edge structure, and X-ray photoelectron spectroscopy. The catalytic activity was tested in [...] Read more.
MnOx-ZrO2 catalysts prepared by co-precipitation and vacuum impregnation were calcined at 400–800 °C and characterized by powder X-ray diffraction, textural studies, high-resolution transmission electron microscopy, temperature-programmed reduction, X-ray absorption near edge structure, and X-ray photoelectron spectroscopy. The catalytic activity was tested in the CO oxidation reaction. The activity of the co-precipitated samples exceeds that of the catalysts prepared by vacuum impregnation. The characterization studies showed that the nature of the active component for the catalysts obtained by co-precipitation differs from that of the catalysts obtained by impregnation. In the impregnation series, the most active catalyst was obtained at a temperature of 400 °C; its increased activity is due to the formation of MnO2 oxide nanoparticles containing Mn4+ and low-temperature reducibility. An increase in the synthesis temperature leads to the formation of less active Mn2O3, catalyst sintering, and, accordingly, deterioration of the catalytic properties. In the case of co-precipitation, the most active CO oxidation catalysts are formed by calcination at 650–700 °C in air. In this temperature interval, on the one hand, a MnyZr1−yO2−x solid solution is formed, and on the other hand, a partial separation of mixed oxide begins with the formation of highly dispersed and active MnOx. A further increase in temperature to 800 °C leads to complete decomposition of the solid solution, the release of manganese cations into Mn3O4, and a drop in catalytic activity. Full article
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20 pages, 3997 KiB  
Article
Selective Hydrogenation of 2-Methyl-3-butyn-2-ol in Microcapillary Reactor on Supported Intermetallic PdZn Catalyst, Effect of Support Doping on Stability and Kinetic Parameters
by Lyudmila Okhlopkova, Igor Prosvirin, Mikhail Kerzhentsev and Zinfer Ismagilov
Catalysts 2022, 12(12), 1660; https://doi.org/10.3390/catal12121660 - 17 Dec 2022
Viewed by 1283
Abstract
The development of active, selective, and stable multicrystalline catalytic coatings on the inner surface of microcapillary reactors addresses environmental problems of fine organic synthesis, in particular by reducing the large quantities of reagents and byproducts. Thin-film nanosized bimetallic catalysts based on mesoporous pure [...] Read more.
The development of active, selective, and stable multicrystalline catalytic coatings on the inner surface of microcapillary reactors addresses environmental problems of fine organic synthesis, in particular by reducing the large quantities of reagents and byproducts. Thin-film nanosized bimetallic catalysts based on mesoporous pure titania and doped with zirconia, ceria, and zinc oxide, for use in microreactors, were developed, and the regularities of their formation were studied. The efficiency of PdZn/TixM1−xO2±y (M = Ce, Zr, Zn) in the hydrogenation of 2-methyl-3-butyn 2-ol was studied with an emphasis on the stability of the catalyst during the reaction. The catalytic parameters depend on the adsorption properties and activity of PdZn and Pd(0) active centers. Under reaction conditions, resistance to the decomposition of PdZn is a factor that affects the stability of the catalyst. The zinc-doped coating proved to be the most selective and stable in the reaction of selective hydrogenation of acetylenic alcohols in a microcapillary reactor. This coating retained a high selectivity of 98.2% during long-term testing up to 168 h. Modification of the morphology and electronic structure of the active component, by doping titania with Ce and Zr, is accompanied by a decrease in stability. Full article
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19 pages, 4415 KiB  
Article
Solvent-Free Synthesis of Nickel Nanoparticles as Catalysts for CO2 Hydrogenation to Methane
by Olga V. Netskina, Kirill A. Dmitruk, Alexander A. Paletsky, Svetlana A. Mukha, Alena A. Pochtar, Olga A. Bulavchenko, Igor P. Prosvirin, Andrey G. Shmakov, Anna M. Ozerova, Janna V. Veselovskaya, Olga I. Mazina and Oxana V. Komova
Catalysts 2022, 12(10), 1274; https://doi.org/10.3390/catal12101274 - 19 Oct 2022
Cited by 1 | Viewed by 1680
Abstract
The solid-state combustion method was used to prepare nickel-based catalysts for CO2 hydrogenation from [Ni(C3H4N2)6](NO3)2 and [Ni(C3H4N2)6](ClO4)2. These complexes [...] Read more.
The solid-state combustion method was used to prepare nickel-based catalysts for CO2 hydrogenation from [Ni(C3H4N2)6](NO3)2 and [Ni(C3H4N2)6](ClO4)2. These complexes were synthesized by adding nickel nitrate and perchlorate to melted imidazole. The composition and structure of the obtained complexes was confirmed by ATR FTIR, powder XRD, and elemental analysis. The stages of thermal decomposition of the complexes and their kinetic parameters were established. It was found that incomplete gasification of more thermostable Ni(C3H4N2)6](ClO4)2 led to the formation of carbon, nitrogen, and chlorine impurities. According to powder XRD and XPS, the solid products of gasification of both complexes consist of NiO and Ni0 covered with nickel hydroxide and/or a carbonate layer. In the case of the sample prepared from [Ni(C3H4N2)6](ClO4)2, this layer was pronounced. Therefore, it limits the nickel reduction in the reaction medium of CO2 hydrogenation, even at 450 °C. The surface of the sample prepared from [Ni(C3H4N2)6](NO3)2 contains nickel oxide, which is easily reduced. So, the catalyst active phase is already formed at 250 °C in the presence of CO2 and efficiently catalyzes CO2 hydrogenation as the temperature increases. Therefore, [Ni(C3H4N2)6](NO3)2 is a promising precursor for the CO2 hydrogenation catalyst, and its solvent-free synthesis follows Green Chemistry principles. Full article
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20 pages, 3192 KiB  
Article
Utilization of Response Surface Methodology in Optimization and Modelling of a Microbial Electrolysis Cell for Wastewater Treatment Using Box–Behnken Design Method
by Nhlanganiso Ivan Madondo, Sudesh Rathilal and Babatunde Femi Bakare
Catalysts 2022, 12(9), 1052; https://doi.org/10.3390/catal12091052 - 16 Sep 2022
Cited by 8 | Viewed by 2042
Abstract
A vast quantity of untreated wastewater is discharged into the environment, resulting in contamination of receiving waters. A microbial electrolysis cell (MEC) is a promising bioelectrochemical system (BES) for wastewater treatment and energy production. However, poor design and control of MEC variables may [...] Read more.
A vast quantity of untreated wastewater is discharged into the environment, resulting in contamination of receiving waters. A microbial electrolysis cell (MEC) is a promising bioelectrochemical system (BES) for wastewater treatment and energy production. However, poor design and control of MEC variables may lead to inhibition in the system. This study explored the utilization of Response Surface Methodology (RSM) on the synergistic aspects of MEC and magnetite nanoparticles for wastewater treatment. Influences of temperature (25–35 °C), voltage supply (0.3–1.3 V) and magnetite nanoparticle dosage (0.1–1.0 g) on the biochemical methane potentials (BMPs) were investigated with the aim of optimizing biogas yield, chemical oxygen demand removal and current density. The analysis of variance (ANOVA) technique verified that the quadratic models obtained were substantial, with p-values below 0.05 and high regression coefficients (R2). The optimum biogas yield of 563.02 mL/g VSfed, chemical oxygen demand (COD) removal of 97.52%, and current density of 26.05 mA/m2 were obtained at 32.2 °C, 0.77 V and 0.53 g. The RSM revealed a good comparison between the predicted and actual responses. This study revealed the effective utilization of statistical modeling and optimization to improve the performance of the MEC to achieve a sustainable and eco-friendly situation. Full article
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19 pages, 3730 KiB  
Article
Pyrolysis of Biomass Pineapple Residue and Banana Pseudo-Stem: Kinetics, Mechanism and Valorization of Bio-Char
by Xin Wang, Shuo Yang, Boxiong Shen, Jiancheng Yang and Lianfei Xu
Catalysts 2022, 12(8), 840; https://doi.org/10.3390/catal12080840 - 30 Jul 2022
Cited by 4 | Viewed by 2041
Abstract
Pineapple residue and banana pseudo-stem are waste from agricultural production in tropical zones, and the characteristics of their pyrolysis should be explored for high-value utilization. Kinetics, thermodynamics, reaction mechanism and valorization of bio-char during pyrolysis of these feedstock were conducted in this study. [...] Read more.
Pineapple residue and banana pseudo-stem are waste from agricultural production in tropical zones, and the characteristics of their pyrolysis should be explored for high-value utilization. Kinetics, thermodynamics, reaction mechanism and valorization of bio-char during pyrolysis of these feedstock were conducted in this study. In biomass mainly decomposed at 150–500 °C, there was a significant mass loss peak for banana pseudo-stem at 650 °C. The activation energy range of pineapple residue and banana pseudo-stem, based on a multi-heating rate method, was 159–335 and 169–364 kJ/mol, respectively. Based on the Gaussian multi-peak fitting method, derivative thermogravimetric curves of pineapple residue and banana pseudo-stem were deconvoluted with three or four fitting peaks, based on the key components in biomass. Interaction between intermediates during pyrolysis increased the complexity of kinetic data. The main carbon number of organic volatiles during pyrolysis was C4 and C5 for pineapple residue, and C2 and C3 for banana pseudo-stem. The high content of cellulose and hemicellulose in biomass improved the yield of volatiles. Porous carbon sourced from pineapple residue and banana pseudo-stems had specific capacitance of 375 F/g and 297 F/g at a current density of 0.5 A/g, respectively. This suggested pineapple residue and banana pseudo-stem as a potential feedstock for electrochemical materials. Full article
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15 pages, 3700 KiB  
Article
Soot Oxidation in a Plasma-Catalytic Reactor: A Case Study of Zeolite-Supported Vanadium Catalysts
by Xinbo Zhu, Hanpeng Wu, Jianbin Luo, Jin Liu, Jiahao Yan, Zijian Zhou, Zhengda Yang, Ye Jiang, Geng Chen and Guohua Yang
Catalysts 2022, 12(7), 677; https://doi.org/10.3390/catal12070677 - 21 Jun 2022
Cited by 4 | Viewed by 1423
Abstract
The plasma-catalytic oxidation of soot was studied over zeolite-supported vanadium catalysts, while four types of zeolites (MCM-41, mordenite, USY and 5A) were used as catalyst supports. The soot oxidation rate followed the order of V/MCM-41 > V/mordenite > V/USY > V/5A, while 100% [...] Read more.
The plasma-catalytic oxidation of soot was studied over zeolite-supported vanadium catalysts, while four types of zeolites (MCM-41, mordenite, USY and 5A) were used as catalyst supports. The soot oxidation rate followed the order of V/MCM-41 > V/mordenite > V/USY > V/5A, while 100% soot oxidation was achieved at 54th min of reaction over V/MCM-41 and V/mordenite. The CO2 selectivity of the process follows the opposite order of oxidation rate over the V/M catalyst. A wide range of catalyst characterizations including N2 adsorption–desorption, XRD, XPS, H2-TPR and O2-TPD were performed to obtain insights regarding the reaction mechanisms of soot oxidation in plasma-catalytic systems. The redox properties were recognized to be crucial for the soot oxidation process. The effects of discharge power, gas flow rate and reaction temperature on soot oxidation were also investigated. The results showed that higher discharge power, higher gas flow rate and lower reaction temperature were beneficial for soot oxidation rate. However, these factors would impose a negative effect on CO2 selectivity. The proposed “plasma-catalysis” method possessed the unique advantages of quick response, mild operation conditions and system compactness. The method could be potentially applied for the regeneration of diesel particulate filters (DPF) at low temperatures and contribute to the the emission control of diesel engines. Full article
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12 pages, 3261 KiB  
Article
Decolorization and Degradation of Methyl Orange Azo Dye in Aqueous Solution by the Electro Fenton Process: Application of Optimization
by Abderrazzak Adachi, Faiçal El Ouadrhiri, Mohammed Kara, Ibtissam El Manssouri, Amine Assouguem, Mikhlid H. Almutairi, Roula Bayram, Hanan R. H. Mohamed, Ilaria Peluso, Noureddine Eloutassi and Amal Lahkimi
Catalysts 2022, 12(6), 665; https://doi.org/10.3390/catal12060665 - 17 Jun 2022
Cited by 23 | Viewed by 2689
Abstract
In a batch reactor, the EF advanced oxidation decolorization of aqueous solutions of methyl orange MO, a commercial azo reactive textile dye, was investigated in the presence of two different electrodes. The evaluation included various operational variables such as the IC current [...] Read more.
In a batch reactor, the EF advanced oxidation decolorization of aqueous solutions of methyl orange MO, a commercial azo reactive textile dye, was investigated in the presence of two different electrodes. The evaluation included various operational variables such as the IC current intensity (60 mA, 80 mA, and 100 mA), initial concentration of pollutant MO (20 mg/L, 40 mg/L, and 60 mg/L), initial pH of solution (3, 5, and 7), temperature of solution (20 °C, 30 °C, and 50 °C), and initial concentration of catalyst [Fe2+] (0.1 mM, 0.2 mM, and 0.3 mM) on the discoloration rate. A Box-Behnken Design of Experiment (BBD) was used to optimize the parameters that directly affect the Electro-Fenton (EF) process. Under the optimal experimental conditions such as [Fe2+] = 0.232 mM, pH = 3, IC = 80 mA, [MO] = 60 mg/L, and T = 30 ± 0.1 °C, the maximum discoloration rate achieved was 94.9%. The discoloration of the aqueous MO solution during the treatment time was confirmed by analysis of the UV-visible spectrum. After a review of the literature on organic pollutant degradation, the EF system provided here is shown to be one of the best in terms of discoloration rate when compared to other AOPs. Full article
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11 pages, 4356 KiB  
Article
Hg0 Removal by a Palygorskite and Fly Ash Supported MnO2-CeO2 Catalyst at Low Temperature
by Junwei Wang, Caihong Jiang, Liming Shi, Zhifeng Xue, Xie Wang, Can Xu, Xianlong Zhang and Jianli Zhang
Catalysts 2022, 12(6), 662; https://doi.org/10.3390/catal12060662 - 16 Jun 2022
Cited by 1 | Viewed by 1333
Abstract
MnO2-CeO2/PG-FA catalysts were prepared by supporting MnO2-CeO2 to PG-FA and used to remove Hg0 in simulated flue gas. The results show that MnO2-CeO2/PG-FA catalyst had excellent and stable Hg0 removal [...] Read more.
MnO2-CeO2/PG-FA catalysts were prepared by supporting MnO2-CeO2 to PG-FA and used to remove Hg0 in simulated flue gas. The results show that MnO2-CeO2/PG-FA catalyst had excellent and stable Hg0 removal activity, which was mainly due to the combination effect of the catalytic oxidation activity by MnO2-CeO2 and the adsorption ability by PG-FA. Mn8-Ce0.5/PG-FA (with 8.0% MnO2 and 0.5% CeO2 loading) catalyst showed the highest Hg0 removal efficiency at 140 °C and Hg0 removal efficiency could be maintained above 95% with the space velocity of 6000 h−1 and Hg0 concentration of 160 μg/m3. O2 promoted Hg0 removal by MnO2-CeO2/PG-FA catalyst, while SO2 and H2O had inhibitory effects. In the presence of O2, the inhibitory effect of SO2 and H2O can be obviously weakened. MnO2-CeO2/PG-FA catalysts were characterized with scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption experiments (TPD). The results of SEM and XRD showed that the active components MnO2-CeO2 dispersed well on the surface of PG-FA support. The results of XPS and TPD show that the Hg0 removal process over MnO2-CeO2/PG-FA catalyst included adsorption and oxidation, HgO and HgSO4 were generated and adsorbed on the catalyst. MnO2-CeO2/PG-FA catalyst also showed excellent regeneration performance after Hg0 removal. Full article
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17 pages, 4283 KiB  
Article
Application of Bioelectrochemical System and Magnetite Nanoparticles on the Anaerobic Digestion of Sewage Sludge: Effect of Electrode Configuration
by Nhlanganiso Ivan Madondo, Emmanuel Kweinor Tetteh, Sudesh Rathilal and Babatunde Femi Bakare
Catalysts 2022, 12(6), 642; https://doi.org/10.3390/catal12060642 - 12 Jun 2022
Cited by 8 | Viewed by 2110
Abstract
Conventional anaerobic digestion is currently challenged by limited degradability and low methane production. Herein, it is proposed that magnetic nanoparticles (Fe3O4-NPs) and bioelectrochemical systems can be employed for the improvement of organic content degradation. In this study, the effect [...] Read more.
Conventional anaerobic digestion is currently challenged by limited degradability and low methane production. Herein, it is proposed that magnetic nanoparticles (Fe3O4-NPs) and bioelectrochemical systems can be employed for the improvement of organic content degradation. In this study, the effect of electrode configuration was examined through the application of a bioelectrochemical system and Fe3O4-NPs in anaerobic digestion (AD). A microbial electrolysis cell with cylindrical electrodes (MECC) and a microbial electrolysis cell (MEC) with rectangular electrodes were compared against the traditional AD process. Biochemical methane potential (BMP) tests were carried out using digesters with a working volume of 800 mL charged with 300 mL inoculum, 500 mL substrate, and 1 g Fe3O4-NPs. The electrodes (zinc and copper) of both digesters were inserted inside the BMPs and were powered with 0.4 V for 30 days at 40 °C. The MECC performed better, improving degradability, with enhanced methane percentage (by 49% > 39.1% of the control), and reduced water pollutants (chemical-oxygen demand, total organic carbon, total suspended solids, turbidity, and color) by more than 88.6%. The maximum current density was 33.3 mA/m2, and the coulombic efficiency was 54.4%. The MECC showed a remarkable potential to maximize methane enhancement and pollution removal by adjusting the electrode configuration. Full article
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12 pages, 3366 KiB  
Article
Investigations on Structural, Electronic and Optical Properties of MoS2/CDs Heterostructure via First-Principles Study
by Xianglu Yin, Aijun Teng, Zhi Chang, Peng Yuan, Dongbin Zhang and Jiyang Yu
Catalysts 2022, 12(5), 456; https://doi.org/10.3390/catal12050456 - 20 Apr 2022
Cited by 4 | Viewed by 1702
Abstract
Much effort has been made for MoS2/CDs heterostructure application in the field of photocatalysts. However, the impacts of functional groups of CDs on the properties of the heterostructure are ambiguous. Here, the impacts of hydroxyl, carbonyl, and carboxyl groups of CDs [...] Read more.
Much effort has been made for MoS2/CDs heterostructure application in the field of photocatalysts. However, the impacts of functional groups of CDs on the properties of the heterostructure are ambiguous. Here, the impacts of hydroxyl, carbonyl, and carboxyl groups of CDs on the structural, electronic, and optical properties of MoS2/CDs’ heterostructure were investigated by conducting a first-principles study. The calculated energy band structure and band gap of monolayer MoS2 were consistent with the experimental values. The band gap of MoS2 was obviously decreased after the construction of MoS2/CDs and MoS2/CDs–hydroxyl/carboxyl, thus helping to improve the light adsorption range. However, the band gap of MoS2/CDs–carbonyl was slightly increased compared with that of monolayer MoS2. The CDs with functional groups can spontaneously bind on 2D-MoS2 and form a stable MoS2/CDs heterostructure. It was confirmed that the MoS2/CDs’ heterostructure belongs to the typical type-II band alignment, which contributes to the separation of photogenerated charge and hole. Notably, the carbonyl and carboxyl groups on the CDs obviously reduced the optical absorption intensity of the MoS2/CDs in the ultraviolet region. The hydroxyl groups have little effect on optical absorption intensity. Thus, the CDs with more hydroxyl groups are beneficial to produce a higher photocatalytic performance. This paper reveals the impacts of surface functional groups and provides a promising approach for designing the MoS2/CDs’ heterostructure to enhance the photocatalytic properties. Full article
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Review

Jump to: Research

25 pages, 2461 KiB  
Review
Emission Control of Toluene in Iron Ore Sintering Using Catalytic Oxidation Technology: A Critical Review
by Qiqi Shi, Dongrui Kang, Yuting Wang and Xiao Zhang
Catalysts 2023, 13(2), 429; https://doi.org/10.3390/catal13020429 - 16 Feb 2023
Cited by 1 | Viewed by 1266
Abstract
Iron ore sintering flue gas containing large amounts of volatile organic compounds (VOCs) can form secondary photochemical smog and organic aerosols, thus posing a serious threat to human health and the ecological environment. Catalytic combustion technology has been considered as one of the [...] Read more.
Iron ore sintering flue gas containing large amounts of volatile organic compounds (VOCs) can form secondary photochemical smog and organic aerosols, thus posing a serious threat to human health and the ecological environment. Catalytic combustion technology has been considered as one of the most prospective strategies for VOC elimination. This paper focuses on a review of studies on catalytic removal of typical VOCs (toluene) on transition metal oxide catalysts in recent years, with advances in single metal oxides, multi-oxide composites, and supported metal oxide catalysts. Firstly, the catalytic activities of a series of catalysts for toluene degradation are evaluated and compared, leading to an analysis of the key catalytic indicators that significantly affect the efficiency of toluene degradation. Secondly, the reaction pathway and mechanism of toluene degradation are systematically introduced. Considering the site space and investment cost, the conversion of VOC pollutants to harmless substances using existing selective catalytic reduction (SCR) systems has been studied with considerable effort. Based on the current development of simultaneous multi-pollutant elimination technology, the interaction mechanism between the NH3-SCR reaction and toluene catalytic oxidation on the surface is discussed in detail. Finally, views on the key scientific issues and the challenges faced, as well as an outlook for the future, are presented. This overview is expected to provide a guide for the design and industrial application of NO/VOC simultaneous removal catalysts. Full article
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17 pages, 1784 KiB  
Review
A Review of Synergistic Catalytic Removal of Nitrogen Oxides and Chlorobenzene from Waste Incinerators
by Dongrui Kang, Yao Bian, Qiqi Shi, Jianqiao Wang, Peng Yuan and Boxiong Shen
Catalysts 2022, 12(11), 1360; https://doi.org/10.3390/catal12111360 - 03 Nov 2022
Cited by 6 | Viewed by 2050
Abstract
Emission of harmful gases, nitrogen oxides (NOx), and dioxins pose a serious threat to the human environment; so, it is urgent to control NOx and dioxin emissions. The new regulations for municipal solid waste incineration emissions set new stringent requirements for NO [...] Read more.
Emission of harmful gases, nitrogen oxides (NOx), and dioxins pose a serious threat to the human environment; so, it is urgent to control NOx and dioxin emissions. The new regulations for municipal solid waste incineration emissions set new stringent requirements for NOx and dioxin emission standards. Most of the existing pollutant control technologies focus on single-unit NOx reduction or dioxin degradation. However, the installation of separate NOx and dioxins removal units is space-consuming and costs a lot. Nowadays, the simultaneous elimination of NOx and dioxins in the same facility has been regarded as a promising technology. Due to the extremely high toxicity of dioxins, the less toxic chlorobenzene, which has the basic structure of dioxins, has been commonly used as a model molecule for dioxins in the laboratory. In this review, the catalysts used for nitrogen oxides/chlorobenzene (NOx/CB) co-removal were classified into two types: firstly, non-loaded and loaded transition metal catalysts, and their catalytic properties were summarized and outlined. Then, the interaction of the NH3-SCR reaction and chlorobenzene catalytic oxidation (CBCO) on the catalyst surface was discussed in detail. Finally, the causes of catalyst deactivation were analyzed and summarized. Hopefully, this review may provide a reference for the design and commercial application of NOx/CB synergistic removal catalysts. Full article
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22 pages, 3140 KiB  
Review
The Impact of Alternative Fuels on Ship Engine Emissions and Aftertreatment Systems: A Review
by Shuo Feng, Shirui Xu, Peng Yuan, Yuye Xing, Boxiong Shen, Zhaoming Li, Chenguang Zhang, Xiaoqi Wang, Zhuozhi Wang, Jiao Ma and Wenwen Kong
Catalysts 2022, 12(2), 138; https://doi.org/10.3390/catal12020138 - 23 Jan 2022
Cited by 8 | Viewed by 4237
Abstract
Marine engines often use diesel as an alternative fuel to improve the economy. In recent years, waste oil, biodiesel and alcohol fuel are the most famous research directions among the alternative fuels for diesel. With the rapid development of the shipping industry, the [...] Read more.
Marine engines often use diesel as an alternative fuel to improve the economy. In recent years, waste oil, biodiesel and alcohol fuel are the most famous research directions among the alternative fuels for diesel. With the rapid development of the shipping industry, the air of coastal areas is becoming increasingly polluted. It is now necessary to reduce the emission of marine engines to meet the strict emission regulations. There are many types of alternative fuels for diesel oil and the difference of the fuel may interfere with the engine emissions; however, PM, HC, CO and other emissions will have a negative impact on SCR catalyst. This paper reviews the alternative fuels such as alcohols, waste oils, biodiesel made from vegetable oil and animal oil, and then summarizes and analyzes the influence of different alternative fuels on engine emissions and pollutant formation mechanism. In addition, this paper also summarizes the methods that can effectively reduce the emissions of marine engines; it can provide a reference for the study of diesel alternative fuel and the reduction of marine engine emissions. Full article
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