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6 pages, 2223 KB

Open AccessProceeding Paper

Photocatalytic Degradation of Dyes Using TpPa-COF-Cl₂ Membrane

by Mayu Kawaguchi, Hideyuki Katsumata, Ikki Tateishi, Mai Furukawa and Satoshi Kaneco

Chem. Proc. 2025, 17(1), 1; https://doi.org/10.3390/chemproc2025017001 - 4 Jul 2025

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Covalent organic frameworks (COFs) are photocatalysts composed of covalent bonds of light elements and free of toxic metals. COFs are highly active against dyes. Furthermore, we aimed to improve the utility of COFs by making them into membranes. In this study, by utilizing [...] Read more.

Covalent organic frameworks (COFs) are photocatalysts composed of covalent bonds of light elements and free of toxic metals. COFs are highly active against dyes. Furthermore, we aimed to improve the utility of COFs by making them into membranes. In this study, by utilizing the cross-linked structure of calcium alginate, we succeeded in forming the photocatalyst TpPa-COF-Cl₂ into a membrane without destroying its structure. This was confirmed by characterization such as FT-IR. In addition, methyl orange was decolorized at 450 nm, confirming the photocatalytic activity of the membrane. Full article

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6 pages, 657 KB

Open AccessProceeding Paper

Extraction of Lignin from Sawdust (Chlorophora excelsa)

by Abraham Thomas, Fadimatu N. Dabai, Benjamin O. Aderemi and Yahaya M. Sani

Chem. Proc. 2025, 17(1), 2; https://doi.org/10.3390/chemproc2025017002 - 16 Jul 2025

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Abstract

Sawdust is an abundant source of lignocellulosic biomass, presenting a sustainable alternative to fossil fuels for producing aromatics, fuels, and chemicals. Lignin, a crucial component, can be depolymerized into valuable aromatics or used for polymer synthesis due to its multiple hydroxyl groups. This [...] Read more.

Sawdust is an abundant source of lignocellulosic biomass, presenting a sustainable alternative to fossil fuels for producing aromatics, fuels, and chemicals. Lignin, a crucial component, can be depolymerized into valuable aromatics or used for polymer synthesis due to its multiple hydroxyl groups. This study focuses on extracting lignin from Chlorophora excelsa sawdust via organosolv technology. The characterization of sawdust revealed 41.15% cellulose, 28.63% hemicellulose, and 26.13% lignin. The extraction process involved treating sawdust at varying temperatures (100–200 °C) with an ethanol–water solution and sulfuric acid. The optimal yield of 49.81% lignin occurred at 160 °C, confirming the chemical properties and composition of the extracted lignin. Full article

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8 pages, 2473 KB

Open AccessProceeding Paper

Development of Photocatalytic Reduction Method of Cr(VI) with Modified g-C₃N₄

by Miyu Sato, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata and Satoshi Kaneco

Chem. Proc. 2025, 17(1), 3; https://doi.org/10.3390/chemproc2025017003 - 29 Jul 2025

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Abstract

Hexavalent chromium (Cr(VI)), a common contaminant in industrial wastewater, poses severe health risks due to its carcinogenic and mutagenic properties. Consequently, the development of efficient and environmentally friendly methods to reduce Cr(VI) to the less toxic trivalent chromium (Cr(III)) is of great importance. [...] Read more.

Hexavalent chromium (Cr(VI)), a common contaminant in industrial wastewater, poses severe health risks due to its carcinogenic and mutagenic properties. Consequently, the development of efficient and environmentally friendly methods to reduce Cr(VI) to the less toxic trivalent chromium (Cr(III)) is of great importance. In this study, we present a cost-effective photocatalytic approach using graphitic carbon nitride (g-C₃N₄) modified with 1,3,5-trihydroxybenzene via one-step thermal condensation. The modified photo-catalyst exhibited improved surface area, porosity, visible-light absorption, and a narrowed band gap, all of which contributed to enhanced charge separation. As a result, nearly complete reduction in Cr(VI) was achieved within 90 min under visible-light irradiation. Further optimization of catalyst dosage and EDTA concentration gave even higher reduction efficiency. This work offers a promising strategy for the design of high-performance photocatalysts for environmental remediation. Full article

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9 pages, 1841 KB

Open AccessProceeding Paper

Cu-Modified Zn₆In₂S₉ Photocatalyst for Hydrogen Production Under Visible-Light Irradiation

by Shota Fukuishi, Hideyuki Katsumata, Ikki Tateishi, Mai Furukawa and Satoshi Kaneco

Chem. Proc. 2025, 17(1), 4; https://doi.org/10.3390/chemproc2025017004 - 29 Jul 2025

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Abstract

Copper-doped indium zinc sulfides were synthesized by heating and stirring a mixture of zinc chloride, indium chloride tetrahydrate, thioacetamide, and copper chloride at 180 °C for 18 h. Among these, Zn_5.7Cu_0.3In₂S₉ exhibited a hydrogen-producing activity of [...] Read more.

Copper-doped indium zinc sulfides were synthesized by heating and stirring a mixture of zinc chloride, indium chloride tetrahydrate, thioacetamide, and copper chloride at 180 °C for 18 h. Among these, Zn_5.7Cu_0.3In₂S₉ exhibited a hydrogen-producing activity of 1660 μmol/g·h, which was approximately five times higher than that of pristine indium zinc sulfide. Therefore, the catalyst was characterized to investigate the effect of Cu addition. PL results revealed that the incorporation of Cu reduced the fluorescence intensity, indicating suppressed recombination of photogenerated electron–hole pairs. DRS showed that the Cu addition enhanced optical absorption in the visible-light region and narrowed the band gap. These findings suggest that the incorporation of copper into indium zinc sulfide improves its photocatalytic activity. Full article

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8 pages, 2685 KB

Open AccessProceeding Paper

Dye Decolorization Under Visible Light Irradiation Using Bismuth Subcarbonate

by Kentaro Yamauchi, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata and Satoshi Kaneco

Chem. Proc. 2025, 17(1), 5; https://doi.org/10.3390/chemproc2025017005 - 4 Aug 2025

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Abstract

Commercially available bismuth subcarbonate (Bi₂O₂CO₃) was treated with nitric acid and the surfactant cetyltrimethylammonium bromide. The treated catalysts exhibited enhanced photocatalytic activity compared to pure Bi₂O₂CO₃ in the decolorization of rhodamine B [...] Read more.

Commercially available bismuth subcarbonate (Bi₂O₂CO₃) was treated with nitric acid and the surfactant cetyltrimethylammonium bromide. The treated catalysts exhibited enhanced photocatalytic activity compared to pure Bi₂O₂CO₃ in the decolorization of rhodamine B (RhB) under visible light irradiation. The absorbance at 554 nm gradually decreased over time and disappeared completely within 80 min. The crystal structure, morphology, and optical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The improved photocatalytic activity of the treated catalysts was attributed to partial carbonate removal and the formation of Bi⁵⁺ species. Scavenger experiments indicated that superoxide radicals (·O₂⁻) and photogenerated holes (h⁺) played significant roles in the photocatalytic decolorization of RhB. Full article

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12 pages, 671 KB

Open AccessProceeding Paper

The Role of Industrial Catalysts in Accelerating the Renewable Energy Transition

by Partha Protim Borthakur and Barbie Borthakur

Chem. Proc. 2025, 17(1), 6; https://doi.org/10.3390/chemproc2025017006 - 4 Aug 2025

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Abstract

Industrial catalysts are accelerating the global transition toward renewable energy, serving as enablers for innovative technologies that enhance efficiency, lower costs, and improve environmental sustainability. This review explores the pivotal roles of industrial catalysts in hydrogen production, biofuel generation, and biomass conversion, highlighting [...] Read more.

Industrial catalysts are accelerating the global transition toward renewable energy, serving as enablers for innovative technologies that enhance efficiency, lower costs, and improve environmental sustainability. This review explores the pivotal roles of industrial catalysts in hydrogen production, biofuel generation, and biomass conversion, highlighting their transformative impact on renewable energy systems. Precious-metal-based electrocatalysts such as ruthenium (Ru), iridium (Ir), and platinum (Pt) demonstrate high efficiency but face challenges due to their cost and stability. Alternatives like nickel-cobalt oxide (NiCo₂O₄) and Ti₃C₂ MXene materials show promise in addressing these limitations, enabling cost-effective and scalable hydrogen production. Additionally, nickel-based catalysts supported on alumina optimize SMR, reducing coke formation and improving efficiency. In biofuel production, heterogeneous catalysts play a crucial role in converting biomass into valuable fuels. Co-based bimetallic catalysts enhance hydrodeoxygenation (HDO) processes, improving the yield of biofuels like dimethylfuran (DMF) and γ-valerolactone (GVL). Innovative materials such as biochar, red mud, and metal–organic frameworks (MOFs) facilitate sustainable waste-to-fuel conversion and biodiesel production, offering environmental and economic benefits. Power-to-X technologies, which convert renewable electricity into chemical energy carriers like hydrogen and synthetic fuels, rely on advanced catalysts to improve reaction rates, selectivity, and energy efficiency. Innovations in non-precious metal catalysts, nanostructured materials, and defect-engineered catalysts provide solutions for sustainable energy systems. These advancements promise to enhance efficiency, reduce environmental footprints, and ensure the viability of renewable energy technologies. Full article

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9 pages, 1477 KB

Open AccessProceeding Paper

Preparation of Nanosized Mesoporous Metal Oxides

by Olena Korchuganova, Emiliia Tantsiura, Kamila Abuzarova and Alina M. Balu

Chem. Proc. 2025, 17(1), 7; https://doi.org/10.3390/chemproc2025017007 - 1 Aug 2025

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Abstract

Nowadays, nanosized mesoporous oxides are of increasing interest to scientists. They can be used as components of heterogeneous catalysts, for photo- and electrocatalysis, as gas sensors, etc. For instance, the desired properties in catalysts include a nano size and homogeneity of the particles [...] Read more.

Nowadays, nanosized mesoporous oxides are of increasing interest to scientists. They can be used as components of heterogeneous catalysts, for photo- and electrocatalysis, as gas sensors, etc. For instance, the desired properties in catalysts include a nano size and homogeneity of the particles that form the catalyst. The particle sizes of oxides are set at the initial stage of their formation, as precursors of precipitation in the context of wet chemistry. The creation of optimal conditions is possible through the use of homogeneous precipitation, where the precipitant is formed within the solution itself as a result of a hydrolysis reaction. The resolution of this issue involved the utilization of urea in our experimental setup, obtaining the hydrolysis products of ammonia and carbon dioxide. Consequently, precipitation reactions can be utilized to obtain hydroxides, carbonates, or hydroxy carbonates of metals. The precursors were calcined, obtaining nanosized mesoporous oxides, which can have a wide range of applications. Nanosized 0.1–50 nm metal oxides were obtained, including those aluminum, iron, indium, zinc, nickel, and cobalt. Full article

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9 pages, 2258 KB

Open AccessProceeding Paper

Transition Metal-Doped Cobalt Oxyhydroxide Catalysts with Enhanced Peroxymonosulfate Activation for Dye Decolorization

by Rina Yamamoto, Hideyuki Katsumata, Ikki Tateishi, Mai Furukawa and Satoshi Kaneco

Chem. Proc. 2025, 17(1), 8; https://doi.org/10.3390/chemproc2025017008 - 11 Aug 2025

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Abstract

Sulfate radical-based advanced oxidation processes (AOPs) are effective for removing organic pollutants from wastewater. In this study, transition metal-doped cobalt oxyhydroxide (CoOOH) was synthesized as an efficient peroxymonosulfate (PMS) activator for the decolorization of rhodamine B. Doping CoOOH with transition metals enhanced its [...] Read more.

Sulfate radical-based advanced oxidation processes (AOPs) are effective for removing organic pollutants from wastewater. In this study, transition metal-doped cobalt oxyhydroxide (CoOOH) was synthesized as an efficient peroxymonosulfate (PMS) activator for the decolorization of rhodamine B. Doping CoOOH with transition metals enhanced its PMS activation performance compared with that of pure CoOOH. Notably, the reaction rate constant in the Ni-CoOOH/PMS system was approximately 4.3 times higher than that in the CoOOH/PMS system. The presence of multiple metals in the catalyst facilitated efficient Co²⁺/Co³⁺ redox cycling, resulting in improved PMS activation and more effective organic pollutant removal. This study highlights the potential of CoOOH-based materials for use in environmental remediation technologies utilizing PMS. Full article

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13 pages, 529 KB

Open AccessProceeding Paper

Emerging Catalysts and Techniques in Microalgae-Based Biodiesel Production

by Partha Protim Borthakur and Pranjal Sarmah

Chem. Proc. 2025, 17(1), 9; https://doi.org/10.3390/chemproc2025017009 - 13 Aug 2025

Viewed by 501

Abstract

The production of biodiesel from microalgae presents a sustainable and renewable solution to the growing global energy demands, with catalysts playing a critical role in optimizing the transesterification process. This study examines the emerging catalysts and innovative techniques utilized in converting microalgal lipids [...] Read more.

The production of biodiesel from microalgae presents a sustainable and renewable solution to the growing global energy demands, with catalysts playing a critical role in optimizing the transesterification process. This study examines the emerging catalysts and innovative techniques utilized in converting microalgal lipids into fatty acid methyl esters, emphasizing their impact on reaction efficiency, yield, and environmental sustainability. Sulfuric acid demonstrates excellent performance in in situ transesterification, while NaOH/zeolite achieves high biodiesel yields using ultrasound- and microwave-assisted methods. Metal oxides such as CuO, NiO, and MgO supported on zeolite, as well as ZnAl-layered double hydroxides (LDHs), further enhance reaction performance through their high activity and stability. Enzymatic catalysts, particularly immobilized lipases, provide a more environmentally friendly option, offering high yields (>90%) and the ability to operate under mild conditions. However, their high cost and limited reusability pose significant challenges. Ionic liquid catalysts, such as tetrabutylphosphonium carboxylate, streamline the process by eliminating the need for drying and lipid extraction, achieving yields as high as 98% from wet biomass. The key novelty of this work lies in its detailed focus on the use of ionic liquids and nanocatalysts in microalgae-based biodiesel production, which are often underrepresented in previous reviews that primarily discuss homogeneous and heterogeneous catalysts. Full article

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