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19 pages, 5240 KiB

Open AccessArticle

Catalytic Activation of Hydrogen Peroxide Using Highly Porous Hydrothermally Modified Manganese Catalysts for Removal of Azithromycin Antibiotic from Aqueous Solution

by Fatemeh Hasanpour, Javad Saien and Omid Norouzi

Catalysts 2023, 13(1), 77; https://doi.org/10.3390/catal13010077 - 30 Dec 2022

Cited by 2 | Viewed by 1516

Abstract

Hydrogen peroxide catalytic activation holds great promise in the treatment of persistent pollutants. In this study, the novel Mn-Acac_air/Al, Mn-Acac_arg/Al and Mn-BTC_arg/Al catalysts, supported on Al₂O₃, were applied for rapid hydrogen peroxide activation [...] Read more.

Hydrogen peroxide catalytic activation holds great promise in the treatment of persistent pollutants. In this study, the novel Mn-Acac_air/Al, Mn-Acac_arg/Al and Mn-BTC_arg/Al catalysts, supported on Al₂O₃, were applied for rapid hydrogen peroxide activation and azithromycin antibiotic removal. The catalysts were prepared by the calcination-hydrothermal method under air or argon atmosphere. The characterization confirmed that the modification of manganese with acetylacetonate and benzene-1,3,5-tricarboxylic acid (H₃BTC) O-donor ligands highly improves the catalyst porosity, amorphousity, and abundance of coordinately unsaturated sites, which facilitate the generation of reactive oxygen species. The hydrogen peroxide activation and azithromycin removal reached 98.4% and 99.3% after 40 min using the Mn-BTC_arg/Al catalyst with incredible stability and reusability. Only a 5.2% decrease in activity and less than 2% manganese releasing in solutions were detected after five regeneration cycles under the optimum operating conditions. The removal intermediates were identified by LC-MS/MS analysis, and the pathways were proposed. The hydroxylation and decarboxylation reactions play a key role in the degradation reaction. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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22 pages, 2527 KiB

Open AccessArticle

Analysis of the Catalytic Effects Induced by Alkali and Alkaline Earth Metals (AAEMs) on the Pyrolysis of Beech Wood and Corncob

by Wei Wang, Romain Lemaire, Ammar Bensakhria and Denis Luart

Catalysts 2022, 12(12), 1505; https://doi.org/10.3390/catal12121505 - 24 Nov 2022

Cited by 3 | Viewed by 1512

Abstract

The catalytic pyrolysis of beech wood and corncob was experimentally investigated considering six additives containing alkali and alkaline earth metals (Na₂CO₃, NaOH, NaCl, KCl, CaCl₂ and MgCl₂). Thermogravimetric analyses (TGA) were carried out with raw feedstocks [...] Read more.

The catalytic pyrolysis of beech wood and corncob was experimentally investigated considering six additives containing alkali and alkaline earth metals (Na₂CO₃, NaOH, NaCl, KCl, CaCl₂ and MgCl₂). Thermogravimetric analyses (TGA) were carried out with raw feedstocks and samples impregnated with different concentrations of catalysts. In a bid to better interpret observed trends, measured data were analyzed using an integral kinetic modeling approach considering 14 different reaction models. As highlights, this work showed that cations (Na⁺, K⁺, Ca²⁺, and Mg²⁺) as well as anions (i.e., CO₃²⁻, OH⁻, and Cl⁻) influence pyrolysis in selective ways. Alkaline earth metals were proven to be more effective than alkali metals in fostering biomass decomposition, as evidenced by decreases in the characteristic pyrolysis temperatures and activation energies. Furthermore, the results obtained showed that the higher the basicity of the catalyst, the higher its efficiency as well. Increasing the quantities of calcium- and magnesium-based additives finally led to an enhancement of the decomposition process at low temperatures, although a saturation phenomenon was seen for high catalyst concentrations. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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16 pages, 6982 KiB

Open AccessEditor’s ChoiceArticle

Computational Insights into Ru, Pd and Pt fcc Nano-Catalysts from Density Functional Theory Calculations: The Influence of Long-Range Dispersion Corrections

by Marietjie J. Ungerer and Nora H. De Leeuw

Catalysts 2022, 12(10), 1287; https://doi.org/10.3390/catal12101287 - 21 Oct 2022

Cited by 2 | Viewed by 2498

Abstract

Ruthenium, palladium and platinum fall within the group of noble metals that are widely used in catalysis, especially for the electrocatalytic production of hydrogen. The dominant phase of the bulk Ru metal is hexagonal close-packed (hcp), which has been studied extensively. [...] Read more.

Ruthenium, palladium and platinum fall within the group of noble metals that are widely used in catalysis, especially for the electrocatalytic production of hydrogen. The dominant phase of the bulk Ru metal is hexagonal close-packed (hcp), which has been studied extensively. However, significantly less attention has been paid to the face-centred cubic (fcc) phases, which have been observed in nanoparticles. In this study, we have carried out density functional theory calculations with long-range dispersion corrections [DFT-D2, DFT-D3 and DFT-D3-(BJ)] to investigate the lattice parameters, surface energies and work functions of the (001), (011) and (111) surfaces of Ru, Pd and Pt in the fcc phase. When investigating the surface properties of the three metals, we observed that the DFT-D2 method generally underestimated the lattice parameters by up to 2.2% for Pt and 2.8% for Ru. The surface energies followed the observed trend (111) < (001) < (011) for both Ru and Pd with all three methods, which is comparable to experimental data. For Pt the same trend was observed with DFT-D2 and DFT-D3(BJ), but it deviated to Pt (111) < Pt (011) < Pt (001) for the DFT-D3 method. DFT-D2 overestimated the surface energies for all three Miller Indexes by 82%, 73%, and 60%, when compared to experimental values. The best correlation for the surface energies was obtained with the DFT-D3 and DFT-D3(BJ) methods, both of which have deviate by less than 15% deviation for all surfaces with respect to experiment. The work function followed the trend of Φ (111) < Φ (001) < Φ (011) for all three metals and calculated by all three methods. Five different types of Ru, Pd and Pt nanoparticles were considered, including icosahedral, decahedral, cuboctahedral, cubic and spherical particles of different sizes. The bulk, surface and nanoparticle calculations showed that the DFT-D2 method for Pt overestimated the exchange-correlation, leading to higher energy values that can be contributed erroneously to a more stable structure. The calculations showed that as soon as the surface-to-bulk ratio > 1, the energy per atom resembles bulk energy values. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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16 pages, 2304 KiB

Open AccessArticle

Thermodynamic and Kinetic Study of Carbon Dioxide Hydrogenation on the Metal-Terminated Tantalum-Carbide (111) Surface: A DFT Calculation

by Saeedeh Sarabadani Tafreshi, S. Fatemeh. K. S. Panahi, Narges Taghizade, Maryam Jamaati, Mahkameh Ranjbar and Nora H. de Leeuw

Catalysts 2022, 12(10), 1275; https://doi.org/10.3390/catal12101275 - 19 Oct 2022

Cited by 3 | Viewed by 1653

Abstract

The need to reduce our reliance on fossil fuels and lessen the environmentally harmful effects of CO₂ have encouraged investigations into CO₂ hydrogenation to produce useful products. Transition metal carbides exhibit a high propensity towards CO₂ activation, which makes them [...] Read more.

The need to reduce our reliance on fossil fuels and lessen the environmentally harmful effects of CO₂ have encouraged investigations into CO₂ hydrogenation to produce useful products. Transition metal carbides exhibit a high propensity towards CO₂ activation, which makes them promising candidates as suitable catalysts for CO₂ hydrogenation. Here, we have employed calculations based on the density-functional theory to investigate the reaction network for CO₂ hydrogenation to product molecules on the tantalum-terminated TaC (111) surface, including two routes from either HCOOH* or HOCOH* intermediates. Detailed calculations of the reaction energies and energy barriers along multiple potential catalytic pathways, along with the exploration of all intermediates, have shown that CH₄ is the predominant product yielded through a mechanism involving HCOOH, with a total exothermic reaction energy of −4.24 eV, and energy barriers between intermediates ranging from 0.126 eV to 2.224 eV. Other favorable products are CO and CH₃OH, which are also produced via the HCOOH pathway, with total overall reaction energies of −2.55 and −2.10 eV, respectively. Our calculated thermodynamic and kinetic mechanisms that have identified these three predominant products of the CO₂ hydrogenation catalyzed by the TaC (111) surface explain our experimental findings, in which methane, carbon monoxide, and methanol have been observed as the major reaction products. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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17 pages, 4971 KiB

Open AccessArticle

Comparative Catalytic Performance Study of 12-Tungstophosphoric Heteropoly Acid Supported on Mesoporous Supports for Biodiesel Production from Unrefined Green Seed Canola Oil

by Fahimeh Esmi, Shima Masoumi and Ajay K. Dalai

Catalysts 2022, 12(6), 658; https://doi.org/10.3390/catal12060658 - 15 Jun 2022

Cited by 8 | Viewed by 1977

Abstract

In this study, three solid acid catalysts, namely mesoporous aluminophosphate-supported 12-tungstophosphoric heteropoly acid (HPW/MAP), mesoporous aluminosilicate-supported 12-tungstophosphoric heteropoly acid (HPW/MAS), and gamma alumina-supported 12-tungstophosphoric heteropoly acid (HPW/γ-Al₂O₃) were prepared and characterized. Mesoporous aluminophosphate (MAP) and mesoporous aluminosilicate (MAS) were [...] Read more.

In this study, three solid acid catalysts, namely mesoporous aluminophosphate-supported 12-tungstophosphoric heteropoly acid (HPW/MAP), mesoporous aluminosilicate-supported 12-tungstophosphoric heteropoly acid (HPW/MAS), and gamma alumina-supported 12-tungstophosphoric heteropoly acid (HPW/γ-Al₂O₃) were prepared and characterized. Mesoporous aluminophosphate (MAP) and mesoporous aluminosilicate (MAS) were synthesized via sol-gel and hydrothermal methods, respectively, and 25 wt.% of 12-tungstophosphoric heteropoly acid (HPW) was immobilized on the support materials using the wet impregnation method. The features of the fabricated catalysts were comprehensively investigated using various techniques such as BET, XRD, NH₃-TPD, TGA, and TEM. The surface area of the supported catalysts decreased after HPW impregnation according to BET results, which indicates that HPW loaded on the supports and inside of their pores successfully. The density and strengths of the acid sites of the support materials and the catalysts before reaction and after regeneration were determined by the NH₃-TPD technique. Accordingly, an increase in acidity was observed after HPW immobilization on all the support materials. The catalytic performance of the catalysts was studied through alcoholysis reaction using unrefined green seed canola oil as the feedstock. The maximum biodiesel yield of 82.3% was obtained using 3 wt.% of HPW/MAS, with a methanol to oil molar ratio of 20:1, at 200 °C and 4 MPa over 7 h. The reusability study of HPW/MAS showed that it can maintain 80% of its initial activity after five runs. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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13 pages, 1661 KiB

Open AccessArticle

Addition of Different Biochars as Catalysts during the Mesophilic Anaerobic Digestion of Mixed Wastewater Sludge

by Marco Chiappero, Francesca Cillerai, Franco Berruti, Ondřej Mašek and Silvia Fiore

Catalysts 2021, 11(9), 1094; https://doi.org/10.3390/catal11091094 - 10 Sep 2021

Cited by 12 | Viewed by 2302

Abstract

Biochar (BC) recently gained attention as an additive for anaerobic digestion (AD). This work aims at a critical analysis of the effect of six BCs, with different physical and chemical properties, on the AD of mixed wastewater sludge at 37 °C, comparing their [...] Read more.

Biochar (BC) recently gained attention as an additive for anaerobic digestion (AD). This work aims at a critical analysis of the effect of six BCs, with different physical and chemical properties, on the AD of mixed wastewater sludge at 37 °C, comparing their influence on methane production and AD kinetics. AD batch tests were performed at the laboratory scale operating 48 reactors (0.25 L working volume) for 28 days with the addition of 10 g L⁻¹ of BC. Most reactors supplemented with BCs exhibited higher (up to 22%) methane yields than the control reactors (0.15 Nm³ kg_VS⁻¹). The modified Gompertz model provided maximum methane production rate values, and in all reactors the lag-phase was equal to zero days, indicating a good adaptation of the inoculum to the substrate. The potential correlations between BCs’ properties and AD performance were assessed using principal component analysis (PCA). The PCA results showed a reasonable correlation between methane production and the BCs’ O–C and H–C molar ratios, and volatile matter, and between biogas production and BCs’ pore volume, specific surface area, and fixed and total carbon. In conclusion, the physic-chemical properties of BC (specifically, hydrophobicity and morphology) showed a key role in improving the AD of mixed wastewater sludge. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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Review

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24 pages, 3527 KiB

Open AccessReview

Catalytic Hydropyrolysis of Lignin for the Preparation of Cyclic Hydrocarbon-Based Biofuels

by Sreedhar Gundekari and Sanjib Kumar Karmee

Catalysts 2022, 12(12), 1651; https://doi.org/10.3390/catal12121651 - 15 Dec 2022

Cited by 5 | Viewed by 2510

Abstract

The demand for biomass utilization is increasing because of the depletion of fossil resources that are non-renewable in nature. Lignin is the second most renewable organic carbon source, but currently it has limited scope for application in the chemical and fuel industries. Lignin [...] Read more.

The demand for biomass utilization is increasing because of the depletion of fossil resources that are non-renewable in nature. Lignin is the second most renewable organic carbon source, but currently it has limited scope for application in the chemical and fuel industries. Lignin is a side product of the paper and pulp, sugar, and 2G bioethanol industries. Many research groups are working on the value-addition of lignin. Among the lignin depolymerization methods, catalytic hydropyrolysis is gaining attention and is playing a crucial role in developing biorefinery. The hydropyrolysis of lignin was conducted at a higher temperature in the presence of H₂. The hydropyrolysis of lignin results in the selective formation of non-oxygenated cyclic hydrocarbons in a shorter reaction time. It is possible to use the cyclic hydrocarbons directly as a fuel or they can be blended with conventional gasoline. This review focuses on the prior art of pyrolysis and hydropyrolysis of lignin. Possible products of lignin hydropyrolysis and suitable synthetic routes to obtain non-oxygenated cyclic hydrocarbons are also discussed. The influence of various process parameters, such as type of reactor, metal catalyst, nature of catalytic supports, reaction temperature, and H₂ pressure are discussed with regard to the hydropyrolysis of lignin to achieve good selectivity of cyclic hydrocarbons. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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19 pages, 1224 KiB

Open AccessFeature PaperReview

Hydrochar: A Review on Its Production Technologies and Applications

by Shima Masoumi, Venu Babu Borugadda, Sonil Nanda and Ajay K. Dalai

Catalysts 2021, 11(8), 939; https://doi.org/10.3390/catal11080939 - 02 Aug 2021

Cited by 94 | Viewed by 13005

Abstract

Recently, due to the escalating usage of non-renewable fossil fuels such as coal, natural gas and petroleum coke in electricity and power generation, and associated issues with pollution and global warming, more attention is being paid to finding alternative renewable fuel sources. Thermochemical [...] Read more.

Recently, due to the escalating usage of non-renewable fossil fuels such as coal, natural gas and petroleum coke in electricity and power generation, and associated issues with pollution and global warming, more attention is being paid to finding alternative renewable fuel sources. Thermochemical and hydrothermal conversion processes have been used to produce biochar and hydrochar, respectively, from waste renewable biomass. Char produced from the thermochemical and hydrothermal decomposition of biomass is considered an environmentally friendly replacement for solid hydrocarbon materials such as coal and petroleum coke. Unlike thermochemically derived biochar, hydrochar has received little attention due to the lack of literature on its production technologies, physicochemical characterization, and applications. This review paper aims to fulfill these objectives and fill the knowledge gaps in the literature relating to hydrochar. Therefore, this review discusses the most recent studies on hydrochar characteristics, reaction mechanisms for char production technology such as hydrothermal carbonization, as well as hydrochar activation and functionalization. In addition, the applications of hydrochar, mainly in the fields of agriculture, pollutant adsorption, catalyst support, bioenergy, carbon sequestration, and electrochemistry are reviewed. With advancements in hydrothermal technologies and other environmentally friendly conversion technologies, hydrochar appears to be an appealing bioresource for a wide variety of energy, environmental, industrial, and commercial applications. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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