Catalysts for Water and Air Pollution Control: Present and Future, 2nd Edition

Dear Colleagues,

Following the first successful Special Issue on this topic (available here), we are happy to announce a second edition entitled “Catalysts for Water and Air Pollution Control: Present and Future, 2nd Edition”.

For several years now, the use of catalytic processes for reducing environmental pollution has become essential. Due to increasing restrictions on emission limits, it is necessary to increase efforts and research activities in this area; developing more efficient catalytic processes is becoming evident. A typical example is a complex system currently used for the simultaneous reduction of CO, VOCs, NOx and soot particles in diesel engine exhausts, for which a tandem of several catalytic reactors has been developed. Other examples are Advanced Oxidation Processes (AOP) which remove organic contaminants from water and wastewater using different oxidants such as H₂O₂ or O₃. This issue of catalysts has been dedicated to disseminating results from the efforts of research groups on both the basic and applied aspects of environmental catalysis, which is focused on water and air pollution control, aiming to generate new ideas and stimulate research in this fascinating area. Manuscripts are welcome from a broad spectrum of important topics relating to catalysts, reactors and processes.

Dr. Eduardo Miró
Dr. Ezequiel David Banus
Dr. Juan Pablo Bortolozzi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 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.

• environmental catalysis
• air pollution
• CO, VOCs, NOx added soot particles
• catalytic processes
• water pollution
• photocatalysis
• Emerging Organic Contaminants (EOCs)
• wastewater treatment
• heterogeneous catalysts
• Advanced Oxidation Processes (AOPs)

• Catalysts for Air Pollution Control: Present and Future in Catalysts (10 articles)

Title: Co-Ce clay-based materials: their feasibility as catalysts for soot and CO oxidation reactions
Authors: Eduardo Miró; Ezequiel David Banus; Juan Pablo Bortolozzi
Affiliation: Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (UNL-CONICET), Facultad de Ingeniería Química, Santiago del Estero 2829, Santa Fe 3000, Argentina
Abstract: A series of Co-Ce clay-based catalysts were prepared by the wet impregnation method and then characterized by X-ray diffraction (XRD), Temperature-programmed reduction (TPR), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). These catalysts were tested for the catalytic combustion of diesel soot and carbon monoxide through Temperature-programmed oxidation (TPO) tests. The objective of this work was to found the best composition of the active phase of supported catalysts on a commercial clay, in order to further structure these systems by means of using 3D printing technique. The characterization results indicated that the support was mainly composed of kaolinite and quartz. The mixed oxides had higher activities than the individual ones. The optimal molar composition was found to be Co:Ce = 90:10, which showed a high catalytic activity with a main TPO peak located at 335°C. Thus, a synergistic effect between the two selected metals were verified.

Title: Significant effects of adding mode on low-temperature de-NOx performance and SO2 resistance of MnCeTiOx catalyst prepared by co-precipitation method
Authors: Xi Yang; Hongyan Xue; Lei Wang; Jun Yu; Lupeng Han; Dongsen Mao
Affiliation: School of Chemical and Environmental Engineering, Shanghai Institute of Technology
Abstract: Three MnCeTiOx catalysts with the same composition were prepared by conventional co-precipitation (MCT-C), reverse co-precipitation (MCT-R), and parallel flow co-precipitation (MCT-P), respectively, and their low-temperature SCR performance for de-NOx was evaluated. The textural and structural properties, surface acidity, redox capacity, and reaction mechanism of the catalysts were investigated by a series of characterizations including N2 adsorption and desorption, XRD, SEM, XPS, H2-TPR, NH3-TPD, NO-TPD, and in situ DRIFTs. The results revealed that the most excellent catalytic performance was achieved on MCT-R, and more than 90% NOx conversion can be obtained at 100–300 °C under a high GHSV of 80,000 mL/(gcat⋅h). Furthermore, MCT-R possessed optimal tolerance to H2O and SO2 poisoning. The excellent catalytic performance of MCT-R can be attributed to its larger BET specific surface area, higher contents of Mn4+, Ce3+ and adsorbed oxygen species, and more adsorption capacity for NH3 and NO. Moreover, in situ DRIFTs results indicated that the NH3-SCR reaction follows simultaneously the Langmuir-Hinshelwood and Eley-Rideal mechanisms at 100 °C.

Title: Mechanistic and Kinetic Analysis of Complete Methane Oxidation on a Practical PtPd/Al2O3 Catalyst
Authors: Min Wang, Hai-Ying Chen , ID, Yuliana Lugo-Jose , Joseph M. Fedeyko , Todd J. Toops , and Jacqueline Fidler
Affiliation: Oak Ridge National Laboratory, 2360 Cherahala Blvd., Knoxville, TN 37932, USA
Abstract: A PtPd/Al2O3 catalyst developed for the complete oxidation of methane from ventilation air of underground coal mines is compared against a model PdO/Al2O3 catalyst. Although the PtPd/Al2O3 catalyst is substantially more active and stable than the model catalyst, the nature of active sites between the two catalysts is deemed to be fundamentally the same based on their response to different feed gas compositions and the evolution of surface CO adsorption complexes during time-resolved CO adsorption DRIFTS experiment. For both catalysts, coordinately unsaturated Pd sites are considered as the active centers for methane activation and the subsequent oxidation reaction. H2O competes with CH4 for the same active sites resulting in severe inhibition. Additionally, CH4 oxidation reaction also causes a self-inhibition. Taking both inhibition effects into consideration, a relatively simple kinetic model is developed. The model fits well with the 72 sets of kinetic data collected on the PtPd/Al2O3 catalyst under practically relevant reactions conditions with CH4 concentration in the range of 0.05-0.4%, H2O concentration 1.0 - 5.0%, and reaction temperatures 450 - 700 ℃. Kinetic parameters based on the model suggest that the CH4 activation energy on the PtPd/Al2O3 catalyst is 96.7 kJ/mol and the H2O adsorption energy is -31.0 kJ/mol. Both values are consistent with what have been reported in the literature. The model can be used to develop catalyst sizing guidelines as well as be incorporated in the control algorithm of the catalytic system.