Special Issue "Sustainable and Environmental Catalysis"

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

Deadline for manuscript submissions: closed (31 December 2020) | Viewed by 20973

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Special Issue Editors

Dr. Raffaele Cucciniello
E-Mail Website
Guest Editor
Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy
Interests: environmental catalysis; green chemistry; biomass conversion and valorisation; sampling and catalytic degradation of environmental pollutants
Special Issues, Collections and Topics in MDPI journals
Dr. Daniele Cespi
E-Mail Website
Guest Editor
Head Environmental and Energetic Studies (Line of Business), NIER Ingegneria SpA, Via C. Bonazzi 2 - 40013 - Castel Maggiore, Bologna, Italy
Interests: sustainable development; green chemistry; life cycle assessment (LCA); bio-based industry and products; ISO certification and labelling
Dr. Tommaso Tabanelli
E-Mail Website
Guest Editor
Dipartimento di Chimica Industriale "Toso Montanari", Alma Mater Studiorum Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
Interests: metal nanoparticles; heterogeneous catalysis; nanostructured metal oxides; biomass transformation; in situ and operando techniques
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the last few decades, an increasing amount of interest from academia and industry has been devoted to the application of the 12 Principles of the Green Chemistry in order to pursue the Sustainable Development Goals (SDGs). They are based on the fundamental idea of guiding research and innovation toward more environmentally-friendly practices and solutions. This Special Issue, entitled Sustainable and Environmental Catalysis, will collect original research papers, reviews, short communications, and commentaries reflecting the state-of-the-art and future applications in this field, with particular emphasis on the adoption of green chemistry principles at both a laboratory and industrial scale.

Submissions are especially welcome on (but not limited to) the following topics:

Innovative catalytic processes (both batch and continuous flow) for the valorization of (i) bio-based platform molecules, (ii) wastes, and (iii) industrial processes byproducts;

Catalytic elimination of environmental pollutants;

Preparation, activation–deactivation, characterization, and regeneration of environmental catalysts;

Catalytic reactions to convert wastes into useful products;

Application and characterization of heterogeneous catalysts for the replacement of toxic chemicals for the development of green and environmentally friendly processes.

Manuscripts concerning the application of a life-cycle perspective aimed at evaluating the sustainability of innovative catalytic systems and reaction pathways are strongly encouraged. Issues such as bio-based industry and green chemistry are welcomed.

Prof. Raffaele Cucciniello

Dr. Daniele Cespi

Dr. Tommaso Tabanelli

Guest Editors

Manuscript Submission Information

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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 2200 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
  • Sustainable catalysis
  • Heterogeneous catalysis
  • Continuous flow processes
  • Biomass valorization and bio-based industry
  • Green chemistry principles
  • Life-cycle assessment (LCA)
  • Wastes to value-added products.

Published Papers (16 papers)

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Editorial

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Editorial
Sustainable and Environmental Catalysis
Catalysts 2021, 11(2), 225; https://doi.org/10.3390/catal11020225 - 09 Feb 2021
Viewed by 727
Abstract
Over the last few decades, an increasing amount of interest from academia and industry has been devoted to the application of the Twelve Principles of the Green Chemistry in order to pursue the Sustainable Development Goals (SDGs) recommended by the United Nations [...] [...] Read more.
Over the last few decades, an increasing amount of interest from academia and industry has been devoted to the application of the Twelve Principles of the Green Chemistry in order to pursue the Sustainable Development Goals (SDGs) recommended by the United Nations [...] Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)

Research

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Communication
Base-Free Synthesis of Furfurylamines from Biomass Furans Using Ru Pincer Complexes
Catalysts 2021, 11(5), 558; https://doi.org/10.3390/catal11050558 - 28 Apr 2021
Cited by 5 | Viewed by 1562
Abstract
We report the first example of employing homogeneous organometal-catalyzed transfer hydrogenation for the selective reductive amination of furfurals to furfurylamines. An efficient, chemoselective, and base-free method is described using Ru-MACHO-BH as catalyst and iPrOH as H donor. The method tolerates a range [...] Read more.
We report the first example of employing homogeneous organometal-catalyzed transfer hydrogenation for the selective reductive amination of furfurals to furfurylamines. An efficient, chemoselective, and base-free method is described using Ru-MACHO-BH as catalyst and iPrOH as H donor. The method tolerates a range of substituents affording moderate to excellent yields. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Syntheses, Characterization, and Application of Tridentate Phenoxyimino-Phenoxy Aluminum Complexes for the Coupling of Terminal Epoxide with CO2: From Binary System to Single Component Catalyst
Catalysts 2021, 11(2), 145; https://doi.org/10.3390/catal11020145 - 20 Jan 2021
Cited by 1 | Viewed by 750
Abstract
A series of binuclear aluminum complexes 13 supported by tridentate phenoxyimino-phenoxy ligands was synthesized and used as catalysts for the coupling reaction of terminal epoxide with carbon dioxide. The aluminum complex 1, which is catalytically inactive toward the coupling of epoxide [...] Read more.
A series of binuclear aluminum complexes 13 supported by tridentate phenoxyimino-phenoxy ligands was synthesized and used as catalysts for the coupling reaction of terminal epoxide with carbon dioxide. The aluminum complex 1, which is catalytically inactive toward the coupling of epoxide with CO2 by itself, shows moderate activity in the presence of excess nucleophiles or organic bases at high temperature. In sharp contrast to complex 1, bifunctional complexes 2 and 3, which incorporate tertiary amine groups as the built-in nucleophile, are able to efficiently transform terminal epoxide with CO2 to corresponding cyclic carbonates as a sole product by themselves at 100 °C. The number of amine groups on the ligand skeleton and the reaction temperature exert a great influence on the catalytic activity. The bifunctional complexes 2 and 3 are also active at low carbon dioxide pressure such as 2 atm or atmospheric CO2 pressure. Kinetic studies of the coupling reactions of chloropropylene oxide/CO2 and styrene oxide/CO2 using bifunctional catalysts under atmospheric pressure of CO2 demonstrate that the coupling reaction has a first-order dependence on the concentration of the epoxide. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst
Catalysts 2021, 11(1), 131; https://doi.org/10.3390/catal11010131 - 16 Jan 2021
Cited by 5 | Viewed by 1059
Abstract
Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO [...] Read more.
Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Biojet Fuel Production from Waste of Palm Oil Mill Effluent through Enzymatic Hydrolysis and Decarboxylation
Catalysts 2021, 11(1), 78; https://doi.org/10.3390/catal11010078 - 08 Jan 2021
Cited by 2 | Viewed by 934
Abstract
Palm oil mill effluent (POME), wastewater discharged from the palm oil refinery industry, is classified as an environmental pollutant. In this work, a heterogeneous catalytic process for biojet fuel or green kerosene production was investigated. The enzymatic hydrolysis of POME was firstly performed [...] Read more.
Palm oil mill effluent (POME), wastewater discharged from the palm oil refinery industry, is classified as an environmental pollutant. In this work, a heterogeneous catalytic process for biojet fuel or green kerosene production was investigated. The enzymatic hydrolysis of POME was firstly performed in order to obtain hydrolysed POME (HPOME) rich in free fatty acid (FFA) content. The variations of the water content (30 to 50), temperature (30 to 60 °C) and agitation speed (150 to 250 rpm) were evaluated. The optimal condition for the POME hydrolysis reaction was obtained at a 50% v/v water content, 40 °C and 200 rpm. The highest FFA yield (Y FA) of 90% was obtained. Subsequently, FFA in HPOME was converted into hydrocarbon fuels via a hydrocracking reaction catalysed by Pd/Al2O3 at 400 °C, 10 bars H2 for 1 h under a high pressure autoclave reactor (HPAR). The refined-biofuel yield (94%) and the biojet selectivity (57.44%) were achieved. In this study, we are the first group to successfully demonstrate the POME waste valorisation towards renewable biojet fuel production based on biochemical and thermochemical routes. The process can be applied for the sustainable management of POME waste. It promises to be a high value-added product parallel to the alleviation of wastewater environmental issues. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Morphology-Controlled Synthesis of ZnO Nanostructures for Caffeine Degradation and Escherichia coli Inactivation in Water
Catalysts 2021, 11(1), 63; https://doi.org/10.3390/catal11010063 - 05 Jan 2021
Cited by 7 | Viewed by 970
Abstract
Photocatalytic and antibacterial activity of nanoparticles are strongly governed by their morphology. By varying the type of solvent used, one can obtain different shapes of ZnO nanoparticles and tune the amount of reactive oxygen species (ROS) and metal ion (Zn2+) generation, [...] Read more.
Photocatalytic and antibacterial activity of nanoparticles are strongly governed by their morphology. By varying the type of solvent used, one can obtain different shapes of ZnO nanoparticles and tune the amount of reactive oxygen species (ROS) and metal ion (Zn2+) generation, which in turn dictates their activity. ZnO nanostructures were fabricated via facile wet chemical method by varying the type of solvents. Solar light assisted photocatalytic degradation of caffeine and antibacterial activity against E. coli were examined in presence ZnO nanostructures. In addition to an elaborate nanoparticle characterization, adsorption and kinetic experiments were performed to determine the ability of nanostructures to degrade caffeine. Zone of inhibition, time kill assay and electron microscopy imaging were carried out to assess the antibacterial activity. Experimental findings indicate that ZnO nanospheres generated maximum ROS and Zn2+ ions followed by ZnO nanopetals and ZnO nanorods. As a result, ZnO nanospheres exhibited highest degradation of caffeine as well as killing of E. coli. While ROS is mainly responsible for the photocatalytic activity of nanostructures, their antibacterial activity is mostly due to the combination of ROS, metal ion, physical attrition and cell internalization. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
N-Donor Ligand Supported “ReO2+”: A Pre-Catalyst for the Deoxydehydration of Diols and Polyols
Catalysts 2020, 10(7), 754; https://doi.org/10.3390/catal10070754 - 07 Jul 2020
Cited by 1 | Viewed by 1018
Abstract
A selected number of tetradentate N2Py2 ligand-supported ReO2+ complexes and a monodentate pyridine-supported ReO2+ complex have been investigated as catalysts for the deoxydehydration (DODH) of diols and polyols. In situ 1H NMR experiments showed that [...] Read more.
A selected number of tetradentate N2Py2 ligand-supported ReO2+ complexes and a monodentate pyridine-supported ReO2+ complex have been investigated as catalysts for the deoxydehydration (DODH) of diols and polyols. In situ 1H NMR experiments showed that these N-donor ligand-supported ReO2+ complexes are only the pre-catalyst of the DODH reaction. Treatment of (N2Py2) ReO2+ with an excess amount of water generates an active species for DODH catalysis; use of the Re-product of this reaction shows a much shorter induction period compared to the pristine complex. No ligand is coordinated to the “water-treated” complex indicating that the real catalyst is formed after ligand dissociation. IR analysis suggested this catalyst to be a rhenium-oxide/hydroxide oligomer. The monodentate pyridine ligand is much easier to dissociate from the metal center than a tetradentate N2Py2 ligand, which makes the Py4ReO2+-initiated DODH reaction more efficient. For the Py4ReO2+-initiated DODH of diols and biomass-based polyols, both PPh3 and 3-pentanol could be used as a reductant. Excellent olefin yields are achieved. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Catalytic Cracking of Heavy Crude Oil over Iron-Based Catalyst Obtained from Galvanic Industry Wastes
Catalysts 2020, 10(7), 736; https://doi.org/10.3390/catal10070736 - 03 Jul 2020
Cited by 4 | Viewed by 2159
Abstract
Sewage sludge from the galvanic industry represents a problem to the environment, due to its high metal content that makes it a hazardous waste and must be treated or disposed of properly. This study aimed to evaluate the sludge from three galvanic industries [...] Read more.
Sewage sludge from the galvanic industry represents a problem to the environment, due to its high metal content that makes it a hazardous waste and must be treated or disposed of properly. This study aimed to evaluate the sludge from three galvanic industries and determine its possible use as catalysts for the synthesis of materials. Catalyst was obtained from a thermal process based on dried between 100–120 °C and calcination of sludges between 400 to 700 °C. The physical–chemical properties of the catalyst were analyzed by several techniques as physisorption of N2 and chemisorption of CO of the material. Catalytic activity was analyzed by thermogravimetric analysis of a thermo-catalytic decomposition of crude oil. The best conditions for catalyst synthesis were calcination between 400 and 500 °C, the temperature of reduction between 750 and 850 °C for 15 min. The catalytic material had mainly Fe as active phase and the specific surface between 17.68–96.15 m2·g−1, the catalysts promote around 6% more weight-loss of crude oil in the thermal decomposition compared with assays without the catalyst. The results show that the residual sludge of galvanic industries after thermal treatment can be used as catalytic materials due to the easiness of synthesis procedures required, the low E-factor obtained and the recycling of industrial waste promoted. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
A Highly Efficient Monolayer Pt Nanoparticle Catalyst Prepared on a Glass Fiber Surface
Catalysts 2020, 10(5), 472; https://doi.org/10.3390/catal10050472 - 25 Apr 2020
Cited by 4 | Viewed by 1032
Abstract
Over the past few years, various nanoparticle-supported precious metal-based catalysts have been investigated to reduce the emission of harmful substances from automobiles. Generally, precious metal nanoparticle-based exhaust gas catalysts are prepared using the impregnation method. However, these catalysts suffer from the low catalytic [...] Read more.
Over the past few years, various nanoparticle-supported precious metal-based catalysts have been investigated to reduce the emission of harmful substances from automobiles. Generally, precious metal nanoparticle-based exhaust gas catalysts are prepared using the impregnation method. However, these catalysts suffer from the low catalytic activity of the precious metal nanoparticles involved. Therefore, in this study, we developed a novel method for preparing highly efficient glass fiber-supported Pt nanoparticle catalysts. We uniformly deposited a single layer of platinum particles on the support surface using a chemically adsorbed monomolecular film. The octane combustion performance of the resulting catalyst was compared with that of a commercial catalyst. The precious metal loading ratio of the proposed catalyst was approximately seven times that of the commercial catalyst. Approximately one-twelfth of the mass of the proposed catalyst exhibited a performance comparable to that of the commercial catalyst. Thus, the synthesis method used herein can be used to reduce the weight, size, and manufacturing cost of exhaust gas purification devices used in cars. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Kinetic and Mechanistic Study of Rhodamine B Degradation by H2O2 and Cu/Al2O3/g-C3N4 Composite
Catalysts 2020, 10(3), 317; https://doi.org/10.3390/catal10030317 - 10 Mar 2020
Cited by 14 | Viewed by 1664
Abstract
The classic Fenton reaction, which is driven by iron species, has been widely explored for pollutant degradation, but is strictly limited to acidic conditions. In this work, a copper-based Fenton-like catalyst Cu/Al2O3/g-C3N4 was proposed that achieves [...] Read more.
The classic Fenton reaction, which is driven by iron species, has been widely explored for pollutant degradation, but is strictly limited to acidic conditions. In this work, a copper-based Fenton-like catalyst Cu/Al2O3/g-C3N4 was proposed that achieves high degradation efficiencies for Rhodamine B (Rh B) in a wide range of pH 4.9–11.0. The Cu/Al2O3 composite was first prepared via a hydrothermal method followed by a calcination process. The obtained Cu/Al2O3 composite was subsequently stabilized on graphitic carbon nitride (g-C3N4) by the formation of C−O−Cu bonds. The obtained composites were characterized through FT-IR, XRD, TEM, XPS, and N2 adsorption/desorption isotherms, and the immobilized Cu+ was proven to be active sites. The effects of Cu content, g-C3N4 content, H2O2 concentration, and pH on Rh B degradation were systematically investigated. The effect of the catalyst dose was confirmed with a specific reaction rate constant of (5.9 ± 0.07) × 10−9 m·s−1 and the activation energy was calculated to be 71.0 kJ/mol. In 100 min 96.4% of Rh B (initial concentration 20 mg/L, unadjusted pH (4.9)) was removed in the presence of 1 g/L of catalyst and 10 mM of H2O2 at 25 °C, with an observed reaction rate constant of 6.47 × 10−4 s−1. High degradation rates are achieved at neutral and alkaline conditions and a low copper leaching (0.55 mg/L) was observed even after four reaction cycles. Hydroxyl radical (HO·) was identified as the reactive oxygen species by using isopropanol as a radical scavenger and by ESR analysis. HPLC-MS revealed that the degradation of Rh B on Cu/Al2O3/CN composite involves N-de-ethylation, hydroxylation, de-carboxylation, chromophore cleavage, ring opening, and the mineralization process. Based on the results above, a tentative mechanism for the catalytic performance of the Cu/Al2O3/g-C3N4 composite was proposed. In summary, the characteristics of high degradation rate constants, low ion leaching, and the excellent applicability in neutral and alkaline conditions prove the Cu/Al2O3/g-C3N4 composite to be a superior Fenton-like catalyst compared to many conventional ones. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Effect of Zirconia on Hydrothermally Synthesized Co3O4/TiO2 Catalyst for NOx Reduction from Engine Emissions
Catalysts 2020, 10(2), 209; https://doi.org/10.3390/catal10020209 - 09 Feb 2020
Cited by 5 | Viewed by 1106
Abstract
Effect of zirconia on the 6 wt.% Co3O4/TiO2 catalyst for NOx reduction is investigated in this paper. Co3O4/TiO2 catalyst was prepared by using hydrothermal method and then was promoted with zirconia by [...] Read more.
Effect of zirconia on the 6 wt.% Co3O4/TiO2 catalyst for NOx reduction is investigated in this paper. Co3O4/TiO2 catalyst was prepared by using hydrothermal method and then was promoted with zirconia by impregnation to get 8% wt. ZrO2-Co3O4/TiO2 catalyst. Catalysts were characterized by using XRD, SEM, and TGA. Catalysts real time activity was tested by coating them on stainless steel wire meshes, containing them in a mild steel shell and mounting them at the exhaust tailpipe of a 72 cm3 motorcycle engine. Zirconia promoted catalyst showed higher conversion efficiency of NOX than the simple Co3O4/TiO2 catalyst due to small crystalline size, fouling inhibition and thermal stability. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Heterogeneous Nanomagnetic Catalyst from Cupriferous Mineral Processing Gangue for the Production of Biodiesel
Catalysts 2019, 9(12), 1047; https://doi.org/10.3390/catal9121047 - 10 Dec 2019
Cited by 1 | Viewed by 1183
Abstract
The commercialisation of biodiesel as an alternative energy source is challenged by high production costs. The cost of feedstock, catalyst and separation of the dissolved catalyst (homogeneous catalyst) from the product are the major contributors to the total manufacturing cost of biodiesel. This [...] Read more.
The commercialisation of biodiesel as an alternative energy source is challenged by high production costs. The cost of feedstock, catalyst and separation of the dissolved catalyst (homogeneous catalyst) from the product are the major contributors to the total manufacturing cost of biodiesel. This study investigated the potential of a heterogeneous catalyst produced from mineral processing waste for biodiesel production. Tailings from the concentration of cupriferous minerals served as the starting material for synthesis of the catalyst. The nanomagnetic catalysts were prepared using co-precipitation (CMCO) and sol-gel (CMSG) methods, combined with zero-valent iron nanoparticles (ZVINPs) to form a hydride catalyst (CMSG/ZVINPs). Catalyst properties were assessed using SEM, TEM, BET and EDX. The catalyst activity was enhanced by a large number of basic sites that were afforded by the presence of calcite and magnesite. Good surface areas and particle sizes of 58.9 m2/g and 15.4 nm, and 52.6 m2/g and 16.9 nm were observed for the catalysts that were prepared using the CMSG and CMCO methods, respectively. 173 emu/g mass magnetisation was obtained for CMSG/ZVINPs, which was sufficient for the catalyst to be regenerated and reused for biodiesel production by exploiting the magnetic properties. The maximum yield obtained with this catalyst was 88% and an average of 27% decrease in biodiesel yield was observed after four reaction cycles. The physicochemical properties of the biodiesel produced complied with the ASTM standard specification. The results showed that mineral processing tailings are a viable starting material for catalyst preparation in biodiesel production. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Low-Temperature Selective Catalytic Reduction of NO with NH3 over Natural Iron Ore Catalyst
Catalysts 2019, 9(11), 956; https://doi.org/10.3390/catal9110956 - 14 Nov 2019
Cited by 8 | Viewed by 1079
Abstract
The selective catalytic reduction of NO with NH3 at low temperatures has been investigated with natural iron ore catalysts. Four iron ore raw materials from different locations were taken and processed to be used as catalysts. The methods of X-ray diffraction (XRD), [...] Read more.
The selective catalytic reduction of NO with NH3 at low temperatures has been investigated with natural iron ore catalysts. Four iron ore raw materials from different locations were taken and processed to be used as catalysts. The methods of X-ray diffraction (XRD), X-ray fluorescence (XRF), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the materials. The results showed that the sample A (comprised mainly of α-Fe2O3 and γ-Fe2O3), calcined at 250 °C, achieved excellent selective catalytic reduction (SCR) activity (above 80% at 170–350 °C) and N2 selectivity (above 90% up to 250 °C) at low temperatures. Suitable calcination temperature, large surface area, high concentration of surface-adsorbed oxygen, good reducibility, lots of acid sites and adsorption of the reactants were responsible for the excellent SCR performance of the iron ore. However, the addition of H2O and SO2 in the feed gas showed some adverse effects on the SCR activity. The FT-IR analysis indicated the formation of sulfate salts on the surface of the catalyst during the SCR reaction in the presence of SO2, which could cause pore plugging and result in the suppression of the catalytic activity. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Fe Speciation in Iron Modified Natural Zeolites as Sustainable Environmental Catalysts
Catalysts 2019, 9(10), 866; https://doi.org/10.3390/catal9100866 - 19 Oct 2019
Cited by 4 | Viewed by 1495
Abstract
Natural purified mordenite from Palmarito de Cauto (ZP) deposit, Cuba, was subjected to a hydrothermal ion exchange process in acid medium with Fe2+ or Fe3+ salts (Fe2+ZP and Fe3+ZP). The set of samples was characterized regarding their [...] Read more.
Natural purified mordenite from Palmarito de Cauto (ZP) deposit, Cuba, was subjected to a hydrothermal ion exchange process in acid medium with Fe2+ or Fe3+ salts (Fe2+ZP and Fe3+ZP). The set of samples was characterized regarding their textural properties, morphology, and crystallinity, and tested in the NO reduction with CO/C3H6. Infrared spectroscopy coupled with NO as a probe molecule was used to give a qualitative description of the Fe species’ nature and distribution. The exchange process caused an increase in the iron loading of the samples and a redistribution, resulting in more dispersed Fe2+ and Fe3+ species. When contacted with the NO probe, Fe2+ZP showed the highest intensity of nitrosyl bands, assigned to NO adducts on isolated/highly dispersed Fe2+/Fe3+ extra-framework sites and FexOy clusters. This sample is also characterized by the highest NO sorption capacity and activity in NO reduction. Fe3+ZP showed a higher intensity of nitrosonium (NO+) species, without a correlation to NO storage and conversion, pointing to the reactivity of small FexOy aggregates in providing oxygen atoms for the NO to NO+ reaction. The same sites are proposed to be responsible for the higher production of CO2 observed on this sample, and thus to be detrimental to the activity in NO SCR. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Article
Oxidative Degradation of Trichloroethylene over Fe2O3-doped Mayenite: Chlorine Poisoning Mitigation and Improved Catalytic Performance
Catalysts 2019, 9(9), 747; https://doi.org/10.3390/catal9090747 - 05 Sep 2019
Cited by 7 | Viewed by 1456
Abstract
Mayenite was recently successfully employed as an active catalyst for trichloroethylene (TCE) oxidation. It was effective in promoting the conversion of TCE in less harmful products (CO2 and HCl) with high activity and selectivity. However, there is a potential limitation to the [...] Read more.
Mayenite was recently successfully employed as an active catalyst for trichloroethylene (TCE) oxidation. It was effective in promoting the conversion of TCE in less harmful products (CO2 and HCl) with high activity and selectivity. However, there is a potential limitation to the use of mayenite in the industrial degradation of chlorinated compounds—its limited operating lifespan owing to chlorine poisoning of the catalyst. To overcome this problem, in this work, mayenite-based catalysts loaded with iron (Fe/mayenite) were prepared and tested for TCE oxidation in a gaseous phase. The catalysts were characterized using different physico-chemical techniques, including XRD, ICP, N2-sorption (BET), H2-TPR analysis, SEM-EDX, XPS FESEM-EDS, and Raman. Fe/mayenite was found to be more active and stable than the pure material for TCE oxidation, maintaining the same selectivity. This result was interpreted as the synergistic effect of the metal and the oxo-anionic species present in the mayenite framework, thus promoting TCE oxidation, while avoiding catalyst deactivation. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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Review

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Review
Recent Catalytic Advances in Hydrotreatment Processes of Pyrolysis Bio-Oil
Catalysts 2021, 11(2), 157; https://doi.org/10.3390/catal11020157 - 23 Jan 2021
Cited by 10 | Viewed by 1529
Abstract
Catalytic hydrotreatment (HT) is one of the most important refining steps in the actual petroleum-based refineries for the production of fuels and chemicals, and it will play also a crucial role for the development of biomass-based refineries. In fact, the utilization of HT [...] Read more.
Catalytic hydrotreatment (HT) is one of the most important refining steps in the actual petroleum-based refineries for the production of fuels and chemicals, and it will play also a crucial role for the development of biomass-based refineries. In fact, the utilization of HT processes for the upgrading of biomass and/or lignocellulosic residues aimed to the production of synthetic fuels and chemical intermediates represents a reliable strategy to reduce both carbon dioxide emissions and fossil fuels dependence. At this regard, the catalytic hydrotreatment of oils obtained from either thermochemical (e.g., pyrolysis) or physical (e.g., vegetable seeds pressing) processes allows to convert biomass-derived oils into a biofuel with properties very similar to conventional ones (so-called drop-in biofuels). Similarly, catalytic hydro-processing also may have a key role in the valorization of other biorefinery streams, such as lignocellulose, for the production of high-added value chemicals. This review is focused on recent hydrotreatment developments aimed to stabilizing the pyrolytic oil from biomasses. A particular emphasis is devoted on the catalyst formulation, reaction pathways, and technologies. Full article
(This article belongs to the Special Issue Sustainable and Environmental Catalysis)
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