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4 pages, 704 KiB

Open AccessProceeding Paper

Carbon Nitride-Based Catalysts for High Pressure CO₂ Photoreduction

by Matteo Tommasi, Francesco Conte, Ilenia Rossetti and Gianguido Ramis

Mater. Proc. 2022, 11(1), 1; https://doi.org/10.3390/materproc2022011001 - 05 Dec 2022

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In this work we focus on carbon nitride materials to improve the conversion and productivity of the photoreduction of CO₂, developing a coupled strategy to optimize materials and operating conditions. The metal-free polymeric catalyst, graphitic carbon nitride (g-C₃N₄ [...] Read more.

In this work we focus on carbon nitride materials to improve the conversion and productivity of the photoreduction of CO₂, developing a coupled strategy to optimize materials and operating conditions. The metal-free polymeric catalyst, graphitic carbon nitride (g-C₃N₄), is a relatively novel material, characterized by a wide absorbance in the visible region and demonstrating a superior performance compared to the commercial titania P25 benchmark, the most used photocatalyst for this application. We used an innovative photoreactor operating at high pressures of up to 20 bar, which is unprecedented in photocatalytic applications where transparent windows are needed. This enabled a boost in the solubility of CO₂ in water when operating the reactor as a tri-phase liquid/gas/solid device and improved the surface adsorption over the catalyst. The best productivity for HCOOH so far achieved with these catalysts at 8 bar, pH = 14 and by using Na₂SO₃ as a hole scavenger was ca. 370 g/h kg_cat. Such productivity is several orders of magnitude higher than the literature values. Full article

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9 pages, 2995 KiB

Open AccessProceeding Paper

Effect of Cryogenic Treatment on the Phase Transformation Temperatures and Latent Heat of Ni₅₄Ti₄₆ Shape Memory Alloy

by Rodrigo A. Martins de Andrade, Maria Clara S. de Castro, Gustavo Reinke, Cláudio T. dos Santos and Tadeu C. da Silva

Mater. Proc. 2022, 11(1), 2; https://doi.org/10.3390/materproc2022011002 - 19 Dec 2022

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Abstract

Deep cryogenic treatment is characterized by subjecting the material to slow and controlled cooling at temperatures of up to approximately −196 °C or 77 K. This treatment has attracted industry interest and has been used in recent years, with relative success, to improve [...] Read more.

Deep cryogenic treatment is characterized by subjecting the material to slow and controlled cooling at temperatures of up to approximately −196 °C or 77 K. This treatment has attracted industry interest and has been used in recent years, with relative success, to improve the properties of metals, especially steels. In this article, we provide a preliminary study on the cryogenic soaking time effect of 6, 12, 24, and 36 h on the temperatures and latent transformation heat of the Ni₅₄Ti₄₆ alloy phase. By differential scanning calorimetry (DSC), the properties of samples subjected to different cryogenic soaking times at −196 °C were determined. The results indicated an increase in the phase transformation temperatures present in the alloy and a decrease in the latent heat of transformation in relation to the cryogenic soaking time. The reduction of 9% in the energy involved in the phase transformation was probably due to microstructural changes, and the increase of up to 14.8% in phase transformation temperatures was probably due to stress relief from the reduction of dislocations. Full article

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5 pages, 2213 KiB

Open AccessProceeding Paper

Synthesis and Characterization of Cross-Linked Polymer–Silica Composite Particles with Multi-Functional Groups

by Yayoi Yoshioka

Mater. Proc. 2022, 11(1), 3; https://doi.org/10.3390/materproc2022011003 - 27 Oct 2023

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Abstract

Two types of core-shell composite particles, each comprising an aromatic poly(esteramide) (PEA) having amide and hydroxyl groups combined with silica (SiO₂), were synthesized. This synthesis was performed by polymerizing two monomers in a mixture of acetone and N,N-dimethylacetamide in the presence [...] Read more.

Two types of core-shell composite particles, each comprising an aromatic poly(esteramide) (PEA) having amide and hydroxyl groups combined with silica (SiO₂), were synthesized. This synthesis was performed by polymerizing two monomers in a mixture of acetone and N,N-dimethylacetamide in the presence of porous SiO₂ particles. The surface morphologies of the resulting composite particles and the PEA loadings were determined to be highly dependent on the reaction solvent composition and the monomer used. Both types of particles exhibited unique adsorption properties depending on the dye being adsorbed and displayed differing adsorption efficiencies. In additional trials, carbon-SiO₂ particles were obtained by heating the PEA-SiO₂ particles to 700 °C under nitrogen. Full article

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8 pages, 4806 KiB

Open AccessProceeding Paper

Surface Treatments on Additively Manufactured Ti6Al4V Parts for the Formation of Photocatalytic Nanostructured Surfaces with Antibacterial Properties

by Ramón Arcas, Lucía Martín, Sales Ibiza, Olga Jordá, Francisco Bosch and Ana Valero-Gómez

Mater. Proc. 2022, 11(1), 4; https://doi.org/10.3390/materproc2022011004 - 27 Oct 2023

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Abstract

Since the emergence of the SARS CoV2 virus, viral and antibacterial disinfection systems have become a global necessity, as well as their effective control and removal. In this context, the improvement of photocatalytic systems for the elimination of microorganisms may play a fundamental [...] Read more.

Since the emergence of the SARS CoV2 virus, viral and antibacterial disinfection systems have become a global necessity, as well as their effective control and removal. In this context, the improvement of photocatalytic systems for the elimination of microorganisms may play a fundamental role. In this work, a photocatalytic disinfection system was developed and evaluated, based on additively manufactured Ti6Al4V parts using near-visible UV light. Several electrochemical and/or thermal treatments were optimized to obtain different nanostructured morphologies. The results show the effectiveness of the photocatalytic effect (∆R) on E. coli bacteria on different Ti6Al4V modified surfaces, reaching ∆R values between 0.4 and 2.4. Full article

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8 pages, 2570 KiB

Open AccessProceeding Paper

Influence of Electrospinning Parameters on the Physicochemical Properties of Polycaprolactone, Chitosan, and Sericin Membranes

by María Oviedo, Yuliet Montoya, Catalina Alvarez and John Bustamante

Mater. Proc. 2022, 11(1), 5; https://doi.org/10.3390/materproc2022011005 - 27 Oct 2023

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Abstract

The use of natural polymers such as sericin (SS) and chitosan (Ch) for developing biomaterials has increased in tissue engineering. To ensure adequate biointegration with the biological environment, the method used to obtain the biomaterial plays an important role, which is why the [...] Read more.

The use of natural polymers such as sericin (SS) and chitosan (Ch) for developing biomaterials has increased in tissue engineering. To ensure adequate biointegration with the biological environment, the method used to obtain the biomaterial plays an important role, which is why the electrospinning technique has been employed due to its versatility with regard to emulating the native extracellular matrix. The present study evaluated the influence of electrospinning parameters on the morphological, chemical, and thermal properties of polycaprolactone (PCL), Ch, and SS composite membranes. To achieve this, experiments were designed with varying manufacturing parameters and SS concentrations. The membranes were then characterized by scanning electron microscopy (SEM), Fourier transforms spectrophotometry (FTIR), and thermogravimetric analysis (TGA). SEM images showed that the electrospinning conditions and SS concentrations allow the development of electrospun membranes with high fibrillar density randomly oriented and fiber diameters below 100 nm. Likewise, the spectra and thermograms of the composite membranes show the possible chemical interactions and thermal behavior, demonstrating the homogeneity and stability of the fibrillar structure. Full article

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8 pages, 3154 KiB

Open AccessProceeding Paper

A Vegetable Oil as Heat Transfer Fluid for Parabolic Trough Collector: Dynamic Performance Analysis under Ouagadougou Climate Conditions

by Boubou Bagré, Sié Zacharie Kam, Yomi Woro Gounkaou, Makinta Boukar, Ibrahim Kolawole Muritala, Harouna Sani Dan Nomao, Korsaga Armand, Antoine Beré and Tizane Daho

Mater. Proc. 2022, 11(1), 6; https://doi.org/10.3390/materproc2022011006 - 04 Jan 2024

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Abstract

In this study, the thermal performance of the parabolic trough collector (PTC) has been addressed under Ouagadougou climate conditions. Thus, after developing a model, the effect of mass flow on PTC performance showed that the Jatropha curcas oil (JCO) temperature difference increases when [...] Read more.

In this study, the thermal performance of the parabolic trough collector (PTC) has been addressed under Ouagadougou climate conditions. Thus, after developing a model, the effect of mass flow on PTC performance showed that the Jatropha curcas oil (JCO) temperature difference increases when the mass flow rate (

\dot{m}

) decreases while the thermal efficiency (

η_{t h}

) increases. For

\dot{m}

of 1 kg s⁻¹, a collector length of 46.8 m or collection area of 230 m² is required to obtain an outlet temperature of 210 °C with an average

η_{t h}

of 82.69%. This paper can support the decision for a demonstration plant implementation regarding JCO use in the CSP plant. Full article

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