Special Issue "Heterogeneous Catalysts for Energy and Environmental Applications"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (31 March 2021).

Special Issue Editors

Dr. Maria Luisa Testa
E-Mail Website
Guest Editor
Institute for the Study of Nanostructured Materials (ISMN)—Italian National Research Council (CNR), Via Ugo La Malfa 153, 90146 Palermo, Italy
Interests: sustainable synthesis of nanomaterials for energy and environmental applications; environmental heterogeneous catalysis; design and synthesis of hybrid organic-inorganic catalysts; synthesis of functionalized material applied to the transformation of biomass components; biofuel production; added-value products; circular chemistry; waste-derived materials; sustainable procedures; process efficiency; microwave- assisted reactions; hybrid materials for wastewater purification
Special Issues and Collections in MDPI journals
Prof. Giuliana Magnacca
E-Mail Website
Guest Editor
Dipartimento di Chimica, Università di Torino, via P. Giuria 7, I-10125 Torino, Italy
Interests: heterogeneous catalysts; materials characterization; surface science; materials for environmental preservation
Dr. Rafael Estevez
E-Mail Website
Guest Editor
Departamento de Química Orgánica, Instituto de Química Fina y Nanoquímica, Universidad de Córdoba, Campus de Excelencia Internacional Agroalimentario CeiA3. Edificio Marie Curie, E 14014 Córdoba, Spain
Interests: heterogeneous catalysis; glycerol valorization; biofuels; bioadditives; microwave-assisted processes
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Due to the negative impacts of fossil fuels and the high pollution of air, soil, and water, environmental preservation is one of the most important challenges for the scientific community. In this context, biomass as a renewable feedstock has been gaining importance in order to meet the global need for fuels and chemicals from sustainability perspectives. Studies on heterogeneous catalysts applied in bio-energy, biomass, and environmental depollution are in dynamic growth. Several types of heterogeneous catalysts (hybrid materials, supported metal oxides, perovskites, zeolites, etc.) have been developed and applied on different fields such as clean energy production, biomass valorization, wastewater treatment, and air depollution.

This Special Issue will collect quality papers about the synthesis and application of materials for energy and environmental applications.

The collected articles will emphasize the surface and structural properties of these heterogeneous catalysts, and focus on the applicability of the materials in the fields of energy, biomass, and environmental preservation. Studies concerning synthesis methods, material characterization, and reaction mechanisms are also welcome.

We are pleased to invite you to submit manuscripts for this Special Issue on Heterogeneous Catalysts for Energy and Environmental Applications, in the form of research papers, communications, letters, and review articles. We look forward to your participation in this Special Issue of Materials.

Dr. Maria Luisa Testa
Prof. Giuliana Magnacca
Dr. Rafael Estevez
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 papers will be 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. Materials is an international peer-reviewed open access semimonthly 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 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

  • energy
  • environmental preservation
  • biomass
  • heterogeneous catalysts
  • material characterization
  • green chemistry

Published Papers (8 papers)

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Research

Article
Removal of Heavy Metal Ions from Wastewaters: An Application of Sodium Trithiocarbonate and Wastewater Toxicity Assessment
Materials 2021, 14(3), 655; https://doi.org/10.3390/ma14030655 - 31 Jan 2021
Cited by 1 | Viewed by 604
Abstract
The synthesis and application of sodium trithiocarbonate (Na2CS3) for the treatment of real galvanic wastewater in order to remove heavy metals (Cu, Cd and Zn) was investigated. A Central Composite Design/Response Surface Methodology (CCD/RSM) was employed to optimize the [...] Read more.
The synthesis and application of sodium trithiocarbonate (Na2CS3) for the treatment of real galvanic wastewater in order to remove heavy metals (Cu, Cd and Zn) was investigated. A Central Composite Design/Response Surface Methodology (CCD/RSM) was employed to optimize the removal of heavy metals from industrial wastewater. Adequacy of approximated data was verified using Analysis of Variance (ANOVA). The calculated coefficients of determination (R2 and R2adj) were 0.9119 and 0.8532, respectively. Application of Na2CS3 conjugated with CCD/RSM allowed Cu, Cd and Zn levels to be decreased and, as a consequence, ∑Cu,Cd,Zn decreased by 99.80%, 97.78%, 99.78%, and 99.69%, respectively, by using Na2CS3 at 533 mg/L and pH 9.7, within 23 min. Implementation of conventional metal precipitation reagents (NaOH, Ca(OH)2 and CaO) at pH 11 within 23 min only decreased ∑Cu,Cd,Zn by 90.84%, 93.97% and 93.71%, respectively. Rotifer Brachionus plicatilis was used to conduct the assessment of wastewater toxicity. Following the application of Na2CS3, after 60 min the mortality of B. plicatilis was reduced from 90% to 25%. Engagement of Na2CS3 under optimal conditions caused the precipitation of heavy metals from the polluted wastewater and significantly decreased wastewater toxicity. In summary, Na2CS3 can be used as an effective heavy metal precipitating agent, especially for Cu, Cd and Zn. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Potassium Ferrate (VI) as the Multifunctional Agent in the Treatment of Landfill Leachate
Materials 2020, 13(21), 5017; https://doi.org/10.3390/ma13215017 - 06 Nov 2020
Cited by 1 | Viewed by 504
Abstract
Possible use of potassium ferrate (VI) (K2FeO4) for the treatment of landfill leachate (pH = 8.9, Chemical Oxygen Demand (COD) 770 mg O2/L, Total Organic Carbon (TOC) 230 mg/L, Total Nitrogen (Total N) 120 mg/L, Total Phosphorus [...] Read more.
Possible use of potassium ferrate (VI) (K2FeO4) for the treatment of landfill leachate (pH = 8.9, Chemical Oxygen Demand (COD) 770 mg O2/L, Total Organic Carbon (TOC) 230 mg/L, Total Nitrogen (Total N) 120 mg/L, Total Phosphorus (Total P) 12 mg/L, Total Coli Count (TCC) 6.8 log CFU/mL (Colony-Forming Unit/mL), Most Probable Number (MPN) of fecal enterococci 4.0 log/100 mL, Total Proteolytic Count (TPC) 4.4 log CFU/mL) to remove COD was investigated. Central Composite Design (CCD) and Response Surface Methodology (RSM) were applied for modelling and optimizing the purification process. Conformity of experimental and predicted data (R2 = 0.8477, Radj2 = 0.7462) were verified using Analysis of Variance (ANOVA). Application of K2FeO4 using CCD/RSM allowed to decrease COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC by 76.2%, 82.6%, 68.3%, 91.6%, 99.0%, 95.8% and 99.3%, respectively, by using K2FeO4 0.390 g/L, at pH = 2.3 within 25 min. Application of equivalent amount of iron (as FeSO4 × 7H2O and FeCl3 × 6H2O) under the same conditions allowed to diminish COD, TOC, Total N, Total P, TCC, MPN of fecal enterococci and TPC only by 38.1%, 37.0%, 20.8%, 95.8%, 94.4%, 58.2%, 90.8% and 41.6%, 45.7%, 29.2%, 95.8%, 92.1%, 58.2%, 90.0%, respectively. Thus, K2FeO4 could be applied as an environmentally friendly reagent for landfill leachate treatment. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Ag2O and NiO Decorated CuFe2O4 with Enhanced Photocatalytic Performance to Improve the Degradation Efficiency of Methylene Blue
Materials 2020, 13(21), 4760; https://doi.org/10.3390/ma13214760 - 25 Oct 2020
Cited by 2 | Viewed by 538
Abstract
Dye wastewater is a serious threat to human health and life. It is an important task for researchers to treat it efficiently. Among many treatment methods, the photo-Fenton method can rapidly degrade organic pollutants. In this study, a ternary photocatalyst, Ag2O-NiO/CuFe [...] Read more.
Dye wastewater is a serious threat to human health and life. It is an important task for researchers to treat it efficiently. Among many treatment methods, the photo-Fenton method can rapidly degrade organic pollutants. In this study, a ternary photocatalyst, Ag2O-NiO/CuFe2O4, was prepared and applied for a photo-Fenton reaction to degrade methylene blue (MB). MB had the best degradation effect when 10 mg of the catalyst were used in an 80 mL reaction system for measurement. The degradation rate of MB was up to 96.67% in 60 min with a high degradation rate constant k=5.67×102min1. The total organic carbon (TOC) degradation rate was 78.64% with a TOC degradation rate constant of k=2.57×102min1. Therefore, this study fully proves that Ag2O-NiO/CuFe2O4 can catalyze the photo-Fenton reaction and effectively degrade MB. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Hydrogen Production through Glycerol Photoreforming on TiO2/Mesoporous Carbon: Influence of the Synthetic Method
Materials 2020, 13(17), 3800; https://doi.org/10.3390/ma13173800 - 28 Aug 2020
Viewed by 756
Abstract
This article explores the effect of the synthetic method of titanium dioxide (TiO2)/C composites (physical mixture and the water-assisted/unassisted sol-gel method) on their photocatalytic activity for hydrogen production through glycerol photoreforming. The article demonstrates that, apart from a high surface area [...] Read more.
This article explores the effect of the synthetic method of titanium dioxide (TiO2)/C composites (physical mixture and the water-assisted/unassisted sol-gel method) on their photocatalytic activity for hydrogen production through glycerol photoreforming. The article demonstrates that, apart from a high surface area of carbon and the previous activation of its surface to favor titania incorporation, the appropriate control of titania formation is crucial. In this sense, even though the amount of incorporated titania was limited by the saturation of carbon surface groups (in our case, ca. 10 wt.% TiO2), the sol-gel process without water addition seemed to be the best method, ensuring the formation of small homogeneously-distributed anatase crystals on mesoporous carbon. In this way, a ca. 110-fold increase in catalyst activity compared to Evonik P25 (expressed as hydrogen micromole per grams of titania) was achieved. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Microwave-Assisted Glycerol Etherification Over Sulfonic Acid Catalysts
Materials 2020, 13(7), 1584; https://doi.org/10.3390/ma13071584 - 30 Mar 2020
Cited by 6 | Viewed by 786
Abstract
Glycerol is the main by-product of biodiesel production. For this reason, its valorization into value-added products, by using green procedures, represents an important goal. Different sulfonic acid silica- or titania-based catalysts were prepared, characterized and tested in the glycerol etherification process, assisted by [...] Read more.
Glycerol is the main by-product of biodiesel production. For this reason, its valorization into value-added products, by using green procedures, represents an important goal. Different sulfonic acid silica- or titania-based catalysts were prepared, characterized and tested in the glycerol etherification process, assisted by microwaves, in order to obtain biodiesel additives. The surface and structural properties of the catalysts were investigated by means of N2 adsorption isotherms, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and acid capacity measurements by X-Ray Fluorescence Spectroscopy (XRF). The best performance in terms of activity was achieved in the presence of the sulfonic function directly linked to the amorphous silica. By the correlation of the structure properties of the materials and their activity, the performance of the catalysts was shown to be influenced mainly by the surface area, pore volume and acidity. Recycling experiments performed over the most active systems showed that the sulfonic silica-based materials maintained their performance during several cycles. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Dehydration of Fructose to 5-HMF over Acidic TiO2 Catalysts
Materials 2020, 13(5), 1178; https://doi.org/10.3390/ma13051178 - 06 Mar 2020
Cited by 9 | Viewed by 1020
Abstract
Different solid sulfonic titania-based catalysts were investigated for the hydrothermal dehydration of fructose to 5-hydroxymethylfurfural (5-HMF). The catalytic behavior of the materials was evaluated in terms of fructose conversion and selectivity to 5-HMF. The surface and structural properties of the catalysts were investigated [...] Read more.
Different solid sulfonic titania-based catalysts were investigated for the hydrothermal dehydration of fructose to 5-hydroxymethylfurfural (5-HMF). The catalytic behavior of the materials was evaluated in terms of fructose conversion and selectivity to 5-HMF. The surface and structural properties of the catalysts were investigated by means of X-ray diffraction (XRD), N2 adsorption isotherms, thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and acid capacity measurements. Special attention was focused on the reaction conditions, both in terms of 5-HMF selectivity and the sustainability of the process, choosing water as the solvent. Among the various process condition studied, TiO2-SO3H catalyzed a complete conversion (99%) of 1.1M fructose and 5-HMF selectivity (50%) and yield (50%) at 165 °C. An important improvement of the HMF selectivity (71%) was achieved when the reaction was carried out by using a lower fructose concentration (0.1M) and lower temperature (140 °C). The catalytic activities of the materials were related to their acid capacities as much as their textural properties. In particular, a counterbalance between the acidity and the structure of the pores in which the catalytic sites are located, results in the key issue for switch the selectivity towards the achievement of 5-HMF. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Mesoporous Acidic Catalysts Synthesis from Dual-Stage and Rising Co-Current Gasification Char: Application for FAME Production from Waste Cooking Oil
Materials 2020, 13(4), 871; https://doi.org/10.3390/ma13040871 - 15 Feb 2020
Cited by 1 | Viewed by 773
Abstract
The main purpose of this work is to investigate the application options of the char produced from gasification plants. Two promising mesoporous acidic catalysts were synthesized using char as a support material. Two char samples were collected from either a dual-stage or a [...] Read more.
The main purpose of this work is to investigate the application options of the char produced from gasification plants. Two promising mesoporous acidic catalysts were synthesized using char as a support material. Two char samples were collected from either a dual-stage or a rising co-current biomass gasification plant. The catalysts produced from both gasification char samples were characterized for their physiochemical and morphological properties using N2 physorption measurement, total acidity evaluation through TPD-NH3, functional groups analysis by FT-IR, and morphology determination via FESEM. Results revealed that the dual-stage char-derived mesoporous catalyst (DSC-SO4) with higher specific surface area and acidic properties provided higher catalytic activity for fatty acid methyl esters (FAME) production from waste cooking oil (WCO) than the mesoporous catalyst obtained from char produced by rising co-current gasification (RCC-SO4). Furthermore, the effects of methanol/oil molar ratio (3:1–15:1), catalyst concentration (1–5 wt.% of oil), and reaction time (30–150 min) were studied while keeping the transesterification temperature constant at 65 °C. The optimal reaction conditions for the transesterification of WCO were 4 wt.% catalyst concentration, 12:1 methanol/oil molar ratio, and 90 min operating time. The optimized reaction conditions resulted in FAME conversions of 97% and 83% over DSC-SO4 and RCC-SO4 catalysts, respectively. The char-based catalysts show excellent reusability, since they could be reused six times without any modification. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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Article
Single-Pot Synthesis of Biodiesel using Efficient Sulfonated-Derived Tea Waste-Heterogeneous Catalyst
Materials 2019, 12(14), 2293; https://doi.org/10.3390/ma12142293 - 18 Jul 2019
Cited by 8 | Viewed by 1240
Abstract
The main purpose of this manuscript is to report the new usage of tea waste (TW) as a catalyst for efficient conversion of palm fatty acid distillate (PFAD) to biodiesel. In this work, we investigate the potential of tea waste char as a [...] Read more.
The main purpose of this manuscript is to report the new usage of tea waste (TW) as a catalyst for efficient conversion of palm fatty acid distillate (PFAD) to biodiesel. In this work, we investigate the potential of tea waste char as a catalyst for biodiesel production before and after sulfonation. The activated sulfonated tea waste char catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), elemental composition (CHNS), nitrogen adsorption-desorption using Brunauer-Emmett-Teller (BET) and ammonia-temperature-programmed desorption (NH3-TPD). The activated tea waste char catalyst shows higher acid density of 31 μmol g−1 as compared to tea waste char of 16 μmol g−1 and higher surface area of 122 m2/g. The optimum fatty acid conversion conditions were found that 4 wt % of catalyst loading with 9:1 of methanol:PFAD for 90 min of reaction time at 65 °C gives 97% free fatty acid (FFA) conversion. In conclusion, the sulfonated tea waste (STW) catalyst showed an impressive catalytic activity towards the esterification of PFAD at optimum reaction conditions with significant recyclability in five successive cycles without any reactivation step. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Energy and Environmental Applications)
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