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Application of Green Catalysts in Industrial and Environmental Processes

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Materials Chemistry".

Deadline for manuscript submissions: closed (28 February 2023) | Viewed by 32540

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Dr. Giorgio Vilardi

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Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Rome, Italy
Interests: process intensification; methanation; P2G; exergy; industrial and environmental catalysis; nano-catalysts production; adsorption; plant units design and modeling; process development and scale-up; dynamic modeling; wastewater treatment
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Dear Colleagues,

The use of nanoparticles in both environmental and industrial catalyzed processes has recently undergone to a remarkable growth, considering the increasing number of published papers on these topics. In this framework, the possibility to synthetize the nano-catalysts with green-based reagents and solvents allows the producers to follow and respect the fundamental pillars of the Green Economy. Nanoparticles can be utilized directly as suspended materials and, more often, are supported by other materials. Both industrial and environmental processes, such as catalyzed methanation (Ni, Fe, and Ru-based catalysts), Fischer–Tropsch processes (Fe(0)-based nano-catalysts), heterogeneous fenton, and dehalogenation processes, can be intensified by means of nano-catalysts employment, mainly because of their peculiar properties related to the quantum size effect. In view of sustainable industrial process development, the green production of the used catalysts represents a fundamental step of the whole process.

In this Special Issue, interested researchers are invited to submit original research papers, as well as review articles, on any of the topics related to the production and/or use of green-based catalysts, with a particular focus on nano-sized catalysts.

Dr. Giorgio Vilardi
Guest Editor

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Keywords

Green processes;
Process intensification;
Industrial catalysis;
Environmental catalysis;
Metallic-based catalysts;
Nanoparticles and microparticles;
Heterogeneous fenton;
Catalyzed methanation.

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Published Papers (11 papers)

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Research

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19 pages, 4413 KiB

Open AccessArticle

Tailoring the Composition of Ba_xBO₃ (B = Fe, Mn) Mixed Oxides as CO or Soot Oxidation Catalysts in Simulated GDI Engine Exhaust Conditions

by Álvaro Díaz-Verde, Salvador Montilla-Verdú, Verónica Torregrosa-Rivero and María-José Illán-Gómez

Molecules 2023, 28(8), 3327; https://doi.org/10.3390/molecules28083327 - 9 Apr 2023

Cited by 6 | Viewed by 1709

Abstract

Mixed oxides with perovskite-type structure (ABO₃) are promising catalysts for atmospheric pollution control due to their interesting and tunable physicochemical properties. In this work, two series of Ba_xMnO₃ and Ba_xFeO₃ (x = 1 and 0.7) catalysts were synthesized using the sol–gel method adapted to aqueous medium. The samples were characterized by μ-XRF, XRD, FT-IR, XPS, H₂-TPR, and O₂-TPD. The catalytic activity for CO and GDI soot oxidation was determined by temperature-programmed reaction experiments (CO-TPR and soot-TPR, respectively). The results reveal that a decrease in the Ba content improved the catalytic performance of both catalysts, as B0.7M-E is more active than BM-E for CO oxidation, and B0.7F-E presents higher activity than BF for soot conversion in simulated GDI engine exhaust conditions. Manganese-based perovskites (BM-E and B0.7M-E) achieve better catalytic performance than iron-based perovskite (BF) for CO oxidation reaction due to the higher generation of actives sites. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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16 pages, 1497 KiB

Open AccessArticle

A Series of Green Oxovanadium(IV) Precatalysts with O, N and S Donor Ligands in a Sustainable Olefins Oligomerization Process

by Mariusz Urbaniak, Kacper Pobłocki, Paweł Kowalczyk, Karol Kramkowski, Joanna Drzeżdżon, Barbara Gawdzik, Patrycja Świtała, Maja Miler, Daria Heleniak, Przemysław Rybiński and Dagmara Jacewicz

Molecules 2022, 27(22), 8038; https://doi.org/10.3390/molecules27228038 - 19 Nov 2022

Cited by 7 | Viewed by 1787

Abstract

Designing catalyst systems based on transition metal ions and activators using the principles of green chemistry is a fundamental research goal of scientists due to the reduction of poisonous solvents, metal salts and organic ligands released into the environment. Urgent measures to reduce climate change are in line with the goals of sustainable development and the new restrictive laws ordained by the European Union. In this report, we attempted to use known oxovanadium(IV) green complex compounds with O, N and S donor ligands, i.e., [VO(TDA)phen] • 1.5 H₂O (TDA = thiodiacetate), (phen = 1,10-phenanthroline), oxovanadium(IV) microclusters with 2-phenylpyridine (oxovanadium(IV) cage), [VOO(dipic)(2-phepyH)] • H₂O (dipic = pyridine-2,6-dicarboxylate anion), (2-phepyH = 2-phenylpyridine), [VO(dipic)(dmbipy)] • 2H₂O (dmbipy = 4,4′-dimethoxy-2,2′-dipyridyl) and [VO(ODA)(bipy)] • 2 H₂O (ODA = oxydiacetate), (bipy = 2,2′-bipyridine), as precatalysts in oligomerization reactions of 3-buten-2-ol, 2-propen-1-ol, 2-chloro-2-propen-1-ol and 2,3-dibromo-2-propen-1-ol. The precatalysts, in most cases, turned out to be highly active because the catalytic activity exceeded 1000 g mmol⁻¹·h⁻¹. In addition, the oligomers were characterized by Fourier-transform infrared spectroscopy (FTIR), matrix-assisted laser desorption/ionization (MALDI-TOF-MS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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16 pages, 5823 KiB

Open AccessArticle

Glycerol-Based Retrievable Heterogeneous Catalysts for Single-Pot Esterification of Palm Fatty Acid Distillate to Biodiesel

by Balkis Hazmi, Mahnoush Beygisangchin, Umer Rashid, Wan Nur Aini Wan Mokhtar, Toshiki Tsubota, Ali Alsalme and Chawalit Ngamcharussrivichai

Molecules 2022, 27(20), 7142; https://doi.org/10.3390/molecules27207142 - 21 Oct 2022

Cited by 5 | Viewed by 2264

Abstract

The by-product of the previous transesterification, glycerol was utilised as an acid catalyst precursor for biodiesel production. The crude glycerol was treated through the sulfonation method with sulfuric acid and chlorosulfonic acid in a reflux batch reactor giving solid glycerol-SO₃H and glycerol-ClSO₃H, respectively. The synthesised acidic glycerol catalysts were characterised by various analytical techniques such as thermalgravimetric analyser (TGA), infrared spectroscopy, surface properties adsorption-desorption by nitrogen gas, ammonia-temperature programmed desorption (NH₃-TPD), X-ray diffraction spectroscopy (XRD), elemental composition analysis by energy dispersive spectrometer (EDX) and surface micrographic morphologies by field emission electron microscope (FESEM). Both glycerol-SO₃H and glycerol-ClSO₃H samples exhibited mesoporous structures with a low surface area of 8.85 mm²/g and 4.71 mm²/g, respectively, supported by the microscopic image of blockage pores. However, the acidity strength for both catalysts was recorded at 3.43 mmol/g and 3.96 mmol/g, which is sufficient for catalysing PFAD biodiesel at the highest yield. The catalytic esterification was optimised at 96.7% and 98.2% with 3 wt.% of catalyst loading, 18:1 of methanol-PFAD molar ratio, 120 °C, and 4 h of reaction. Catalyst reusability was sustained up to 3 reaction cycles due to catalyst deactivation, and the insight investigation of spent catalysts was also performed. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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17 pages, 3406 KiB

Open AccessArticle

Photo-Assisted Removal of Rhodamine B and Nile Blue Dyes from Water Using CuO–SiO₂ Composite

by Muhammad Yaseen, Muhammad Humayun, Abbas Khan, Muhammad Idrees, Nasrullah Shah and Shaista Bibi

Molecules 2022, 27(16), 5343; https://doi.org/10.3390/molecules27165343 - 22 Aug 2022

Cited by 20 | Viewed by 2944

Abstract

Wastewater from the textile industries contaminates the natural water and affects the aquatic environment, soil fertility and biological ecosystem through discharge of different hazardous effluents. Therefore, it is essential to remove such dissolved toxic materials from water by applying more efficient techniques. We performed a comparative study on the removal of rhodamine B (RhB) and Nile blue (NB) from water through a catalytic/photocatalytic approach while using a CuO–SiO₂ based nanocomposite. The CuO–SiO₂ nanocomposite was synthesized through a sol–gel process using copper nitrate dihydrate and tetraethylorthosilicate as CuO and SiO₂ precursors, respectively, with ammonia solution as the precipitating agent. The synthesized nanocomposites were characterized, for their structure, morphology, crystallinity, stability, surface area, pore size and pore volume, by using a scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) techniques. The CuO–SiO₂ nanocomposite was used for potential environmental applications in the terms of its catalytic and photocatalytic activities toward the degradation of rhodamine B (RhB) and Nile blue (NB) dyes, in the presence and absence of light, while monitoring the degradation process of dyes by UV-Visible spectroscopy. The catalytic efficiency of the same composite was studied and discussed in terms of changes in the chemical structures of dyes and other experimental conditions, such as the presence and absence of light. Moreover, the composite showed 85% and 90% efficiency towards the removal of rhodamine B and Nile blue dyes respectively. Thus, the CuO–SiO₂ nanocomposite showed better efficiency toward removal of Nile blue as compared to rhodamine B dye while keeping other experimental variables constant. This can be attributed to the structure–property relationships and compatibility of a catalyst with the molecular structures of dyes. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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23 pages, 7480 KiB

Open AccessArticle

Mineral Montmorillonite Valorization by Developing Ni and Mo–Ni Catalysts for Third-Generation Green Diesel Production

by Sotiris Lycourghiotis, Eleana Kordouli, John Zafeiropoulos, Christos Kordulis and Kyriakos Bourikas

Molecules 2022, 27(3), 643; https://doi.org/10.3390/molecules27030643 - 19 Jan 2022

Cited by 8 | Viewed by 1894

Abstract

Four Ni catalysts and one Mo–Ni catalyst supported on montmorillonite were synthesized, characterized by various techniques and evaluated, under solvent-free conditions, for the production of green diesel from waste cooking oil. The optimum Ni content was found to be 20 wt.%. The addition of 2 wt.% Mo to the catalyst resulted in a considerable increase in the amount of green diesel hydrocarbons. The Mo species, moreover, led to a decrease in the (C15 + C17)/(C16 + C18) ratio, which is beneficial from the viewpoint of carbon atom economy. The promoting action of Mo was mainly attributed to the synergy between the oxygen vacancies on the surface of the well-dispersed Mo(V) and Mo(VI) oxides and the neighboring Ni⁰ sites. The optimum reaction conditions, for achieving a proportion of liquid product in the green diesel hydrocarbons (C15–18) equal to 96 wt.%, were found to be 350 °C, 3 g of catalyst per 100 mL of waste cooking oil and 13 h reaction time. These conditions correspond to an LHSV of 2.5 h⁻¹, a value that is considered quite reliable from the viewpoint of industrial applications. Thus, the cheap and abundant mineral montmorillonite is proved a promising support for developing efficient Ni–Mo catalysts for green diesel production. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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16 pages, 1928 KiB

Open AccessArticle

Tungsten and Molybdenum Heteropolyanions with Different Central Ions—Correlation between Theory and Experiment

by Piotr Niemiec, Renata Tokarz-Sobieraj and Małgorzata Witko

Molecules 2022, 27(1), 187; https://doi.org/10.3390/molecules27010187 - 29 Dec 2021

Cited by 3 | Viewed by 2098

Abstract

Density functional theory calculations were carried out to investigate the electronic structures of Keggin-typed [XMo₁₂O₄₀]ⁿ⁻ and [XW₁₂O₄₀]ⁿ⁻ anions with different heteroatoms (X = Zn²⁺, B³⁺, Al³⁺, Ga³⁺, Si⁴⁺, Ge⁴⁺, P⁵⁺, As⁵⁺, and S⁶⁺). The influence of solvent on redox properties of heteropolyanions was discussed. For [XW₁₂O₄₀]ⁿ⁻ systems two linear correlation: first, between the experimental redox potential and energies of LUMO orbital; and second, between the experimental redox potential and total energy interaction (calculated between internal tetrahedron (XO₄ⁿ⁻), and rest of Kegging anion skeleton, (W₁₂O₃₆)) were designated. Taking into account the similarity of XW₁₂O₄₀ⁿ⁻ and XMo₁₂O₄₀ⁿ⁻ systems (in geometry and electronic structure), the estimated redox potential of molybdenum heteropolyanions (with X being p block elements) in different solvent were proposed. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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15 pages, 5620 KiB

Open AccessFeature PaperArticle

Preparation of KI/Hydroxyapatite Catalyst from Phosphate Rocks and Its Application for Improvement of Biodiesel Production

by Widayat Widayat, Hadiyanto Hadiyanto, Permadi Wisnu Aji Wardani, Ummi Az Zuhra and Jedy Prameswari

Molecules 2020, 25(11), 2565; https://doi.org/10.3390/molecules25112565 - 31 May 2020

Cited by 14 | Viewed by 2596

Abstract

The main aim of this work was to investigate the suitability of a KI/KIO₃ impregnated hydroxyapatite (HAP) catalyst derived from natural phosphate rocks for biodiesel production. This study evaluated the effect of impregnation concentrations (1–6% w/w) on the catalyst performance in biodiesel production. The biodiesel was produced from waste cooking oil (WCO) under simultaneous esterification-transesterification reactions at 60 °C for 6 h. The results showed that the biodiesel yield increased by increasing impregnation concentration and the maximum yield (91.787%) was achieved at an impregnation concentration of 5% w/w. The KI/HAP catalyst showed better performance (91.78% biodiesel yield, 59.1% FAME yield and surface area of 13.513 m²/g) as compared to the KIO₃/HAP catalyst (90.07% biodiesel yield, 55.0% FAME yield and surface area of 10.651 m²/g). Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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15 pages, 4474 KiB

Open AccessArticle

Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater

by Chunlei Jiao, Xiao Tan, Aijun Lin and Wenjie Yang

Molecules 2020, 25(1), 47; https://doi.org/10.3390/molecules25010047 - 21 Dec 2019

Cited by 23 | Viewed by 3358

Abstract

Nanometer zero-valent iron (nZVI) has been widely used in the treatment of heavy metals such as hexavalent chromium (Cr(VI)). A novel composite of bead string-structured nZVI on modified activated carbon (nZVI–MAC) is prepared here, using polyethylene glycol as the stable dispersant rather than traditional ethanol during the loading process. The microstructure characterization shows that nZVI particles are loaded on MAC with a bead string structure in large quantity and stably due to the addition of hydroxyl functional groups on the surface by polyethylene glycol. Experiments on the treatment of Cr(VI) in wastewater show that the reaction process requires only 20 min to achieve equilibrium. The removal rate of Cr(VI) with a low concentration (80–100 mg/L) is over 99% and the maximum saturation removal capacity is up to 66 mg/g. The system converts Cr(VI) to trivalent chromium (Cr(III)) through an oxidation-reduction effect and forms an insoluble material with iron ions by coprecipitation, which is then adsorbed on the surface of the nZVI–MAC. The process conforms to the quasi-second order adsorption kinetics equation (mainly chemical adsorption process). Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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Review

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22 pages, 7025 KiB

Open AccessReview

A Comprehensive Review on Zeolite Chemistry for Catalytic Conversion of Biomass/Waste into Green Fuels

by Umair Yaqub Qazi, Rahat Javaid, Amir Ikhlaq, Asif Hussain Khoja and Faisal Saleem

Molecules 2022, 27(23), 8578; https://doi.org/10.3390/molecules27238578 - 5 Dec 2022

Cited by 12 | Viewed by 3672

Abstract

Numerous attempts have been made to produce new materials and technology for renewable energy and environmental improvements in response to global sustainable solutions stemming from fast industrial expansion and population growth. Zeolites are a group of crystalline materials having molecularly ordered micropore arrangements. Over the past few years, progress in zeolites has been observed in transforming biomass and waste into fuels. To ensure effective transition of fossil energy carriers into chemicals and fuels, zeolite catalysts play a key role; however, their function in biomass usage is more obscure. Herein, the effectiveness of zeolites has been discussed in the context of biomass transformation into valuable products. Established zeolites emphasise conversion of lignocellulosic materials into green fuels. Lewis acidic zeolites employ transition of carbohydrates into significant chemical production. Zeolites utilise several procedures, such as catalytic pyrolysis, hydrothermal liquefaction, and hydro-pyrolysis, to convert biomass and lignocelluloses. Zeolites exhibit distinctive features and encounter significant obstacles, such as mesoporosity, pore interconnectivity, and stability of zeolites in the liquid phase. In order to complete these transformations successfully, it is necessary to have a thorough understanding of the chemistry of zeolites. Hence, further examination of the technical difficulties associated with catalytic transformation in zeolites will be required. This review article highlights the reaction pathways for biomass conversion using zeolites, their challenges, and their potential utilisation. Future recommendations for zeolite-based biomass conversion are also presented. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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24 pages, 3763 KiB

Open AccessReview

Recent Advancements and Challenges in Lignin Valorization: Green Routes towards Sustainable Bioproducts

by Mati Ullah, Pengyang Liu, Shangxian Xie and Su Sun

Molecules 2022, 27(18), 6055; https://doi.org/10.3390/molecules27186055 - 16 Sep 2022

Cited by 15 | Viewed by 4394

Abstract

The aromatic hetero-polymer lignin is industrially processed in the paper/pulp and lignocellulose biorefinery, acting as a major energy source. It has been proven to be a natural resource for useful bioproducts; however, its depolymerization and conversion into high-value-added chemicals is the major challenge due to the complicated structure and heterogeneity. Conversely, the various pre-treatments techniques and valorization strategies offers a potential solution for developing a biomass-based biorefinery. Thus, the current review focus on the new isolation techniques for lignin, various pre-treatment approaches and biocatalytic methods for the synthesis of sustainable value-added products. Meanwhile, the challenges and prospective for the green synthesis of various biomolecules via utilizing the complicated hetero-polymer lignin are also discussed. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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18 pages, 2437 KiB

Open AccessReview

New Strategies on Green Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol over Oxide Composites

by Yifei Zhang, Muhammad Shoaib Khalid, Meng Wang and Gao Li

Molecules 2022, 27(17), 5417; https://doi.org/10.3390/molecules27175417 - 24 Aug 2022

Cited by 5 | Viewed by 2722

Abstract

Dimethyl carbonate is a generally used chemical substance which is environmentally sustainable in nature and used in a range of industrial applications as intermediate. Although various methods, including methanol phosgenation, transesterification and oxidative carbonylation of methanol, have been developed for large-scale industrial production of DMC, they are expensive, unsafe and use noxious raw materials. Green production of DMC from CO₂ and methanol is the most appropriate and eco-friendly method. Numerous catalysts were studied and tested in this regard. The issues of low yield and difficulty in tests have not been resolved fundamentally, which is caused by the inherent problems of the synthetic pathway and limitations imposed by thermodynamics. Electron-assisted activation of CO₂ and membrane reactors which can separate products in real-time giving a maximum yield of DMC are also being used in the quest to find more effective production method. In this review paper, we deeply addressed green production methods of DMC using Zr/Ce/Cu-based nanocomposites as catalysts. Moreover, the relationship between the structure and activity of catalysts, catalytic mechanisms, molecular activation and active sites identification of catalysts are also discussed. Full article

(This article belongs to the Special Issue Application of Green Catalysts in Industrial and Environmental Processes)

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