Photocatalytic Decomposition of N2O Over Ceramics Cordierite/CeO2 Nanoparticles

The study is focused on the testing of the photocatalytic ability to decompose nitrous oxide (N2O) over cordierite/CeO2 nanoparticles ceramic photocatalysts. The activity of ceramic materials was compared with the activity of industrially produced TiO2 (Evonik photocatalyst). Photocatalytic decomposition of N2O over the ceramic samples and the TiO2 Evonik was performed in annular batch reactor illuminated with 8 W Hg lamp (λ ═ 254 nm wavelength). Reaction kinetics was well described by pseudo 1st rate law. Photocatalytic activity of cordierite/CeO2 was better in comparison with TiO2 Evonik P25. The highest N2O conversion (56%) after 20 h of irradiation in inert gas was achieved over the sample with higher amount of CeO2. This photocatalyst sample was examined for photocatalytic activity in the decomposition of N2O in the three various gaseous feed mixtures. The gaseous feed mixtures were: N2O enriched with O2 (6.5 mol.%); N2O enriched with H2O(25 mol.%) and N2O enriched with mixture of O2 and H2O(6.5 mol.% and 25 mol.%, respectively). It is assumed that the reduced conversion of N2O (47%) observed in the flow of the mixture of N2O and H2Ocould be affected by the sorption of water vapor on/onto the photocatalyst “active sites” causing less penetration of light and thus reducing the efficiency of photocatalytic decomposition of N2O. The presence of oxygen in the N2O mixture had only little effect to photocatalytic decomposition of N2O.

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Hydrothermal Synthesis of Nanosized TiO2 Using Basic Peptizing Agents and their Photocatalytic Activity on the Decomposition of Orange II

Materials Science Forum ◽

10.4028/www.scientific.net/msf.544-545.71 ◽

2007 ◽

Vol 544-545 ◽

pp. 71-74

Author(s):

Jun Ho Kim ◽

Kwon Taek Lim ◽

Gun Dae Lee ◽

Seong Soo Park ◽

Seong Soo Hong

Keyword(s):

Photocatalytic Activity ◽

Uv Light ◽

Batch Reactor ◽

Anatase Phase ◽

Photocatalytic Decomposition ◽

Molar Ratio ◽

Orange Ii ◽

Titanium Tetraisopropoxide ◽

Peptizing Agent ◽

Hydrolysis Of

TiO2 nanoparticles were prepared using the hydrolysis of titanium tetraisopropoxide (TTIP) using TENOH as a peptizing agent in the hydrothermal method. The physical properties of prepared nanosized TiO2 particles were investigated. The photocatalytic degradation of orange II has been studied using a batch reactor in the presence of UV light. The crystallite size of the anatase phase is increased from 15 to 30 nm as the molar ratio of TENOH/TTIP increases from 0.1 to 1.0. The titania particle prepared at TENOH/TTIP molar ratio=0.1 shows the highest activity on the photocatalytic decomposition of orange II and the photocatalytic activity decreases according to an increase in TENOH/TTIP molar ratio. In addition, the titania particles prepared at 160oC shows the highest activity on the photocatalytic decomposition of orange II

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Photocatalytic degradation of methylene blue from aqueous solutions using nanopillars-TiO2 thin films: Batch reactor studies

Science Vision ◽

10.33493/scivis.18.03.01 ◽

2018 ◽

Vol 18 (3) ◽

pp. 81-91 ◽

Cited By ~ 1

Author(s):

C. Lalhriatpuia

Keyword(s):

Thin Films ◽

Methylene Blue ◽

Photocatalytic Activity ◽

Organic Carbon ◽

Photocatalytic Degradation ◽

Batch Reactor ◽

Tio2 Thin Films ◽

Initial Concentration ◽

Bet Specific Surface Area ◽

Interfering Ions

Nanopillars-TiO2 thin films was obtained on a borosilicate glass substrate with (S1) and without (S2) polyethylene glycol as template. The photocatalytic behaviour of S1 and S2 thin films was assessed inthe degradation of methylene blue (MB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the SEM, XRD, FTIR and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data confirmed that the TiO2 particles are in its anatase mineral phase. The SEM and AFM images indicated the catalyst is composed with nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of MB was well studied at wide range of physico-chemical parameters. The effect of solution pH (pH 4.0 to 10.0) and MB initial concentration (1.0 to 10.0 mg/L) was extensively studied and the effect of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of MB was demonstrated. The maximum percent removal of MB was observed at pH 8.0 beyond which it started decreasing and a low initial concentration of the pollutant highly favoured the photocatalytic degradation using thin films and the presence of several interfering ions diminished the photocatalytic activity of thin films to some extent. The overall photocatalytic activity was in the order: S2 > S1 > UV. The photocatalytic degradation of MB was followed the pseudo-first-order rate kinetics. The mineralization of MB was studied with total organic carbon measurement using the TOC (total organic carbon) analysis.

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Revisiting Glycerol Esterification with Acetic Acid over Amberlyst-35 via Statistically Designed Experiments: Overcoming Transport Limitations

10.26434/chemrxiv.7731305.v1 ◽

2019 ◽

Author(s):

Víctor Gabriel Baldovino Medrano ◽

Karen V. Caballero ◽

Hernando Guerrero-Amaya

Keyword(s):

Acetic Acid ◽

Active Sites ◽

Batch Reactor ◽

Catalyst Particle ◽

Experimental Designs ◽

Particle Sizes ◽

Turnover Rates ◽

Designed Experiments ◽

Different Temperatures ◽

Glycerol Esterification

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

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Use of Nanopillars-TiO2 Thin Films in the Photocatalytic Degradation of Bromophenol Blue from Aqueous Solution

Science & Technology Journal ◽

10.22232/stj.2018.06.01.03 ◽

2018 ◽

Vol 6 (1) ◽

pp. 22-30

Author(s):

C. Lalhriatpuia ◽

◽

Thanhming liana ◽

K. Vanlaldinpuia

Keyword(s):

Thin Films ◽

Aqueous Solution ◽

Photocatalytic Activity ◽

Photocatalytic Degradation ◽

Batch Reactor ◽

Bromophenol Blue ◽

Tio2 Thin Films ◽

Initial Concentration ◽

Bet Specific Surface Area ◽

Interfering Ions

The photocatalytic activity of Nanopillars-TiO2 thin films was assessed in the degradation of Bromophenol blue (BPB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the XRD, SEM and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data showed anatase phase of TiO2 particles with average particle size of 25.4 and 21.9 nm, for S1 and S2 catalysts respectively. The SEM and AFM images indicated the catalyst composed with Nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The average height of the pillars was found to be 180 and 40 nm respectively for the S1 and S2 catalyst. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of BPB using the UV light was studied at wide range of physico-chemical parametric studies to determine the mechanism of degradation as well as the practical applicability of the technique. The batch reactor operations were conducted at varied pH (pH 4.0 to 10.0), BPB initial concentration (1.0 to 20.0 mg/L) and presence of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of BPB. The maximum percent removal of BPB was observed at pH 6.0 and a low initial concentration of the pollutant highly favours the photocatalytic degradation using thin films. The presence of several interfering ions suppressed the photocatalytic activity of thin films to some extent. The time dependence photocatalytic degradation of BPB was demonstrated with the pseudo-first-order rate kinetics. Study was further extended with total organic carbon measurement using the TOC (Total Organic Carbon) analysis. This demonstrated an apparent mineralization of BPB from aqueous solutions.

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Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Materials ◽

10.3390/ma14041043 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1043

Author(s):

Vitor Bonamigo Moreira ◽

Anna Puiggalí-Jou ◽

Emilio Jiménez-Piqué ◽

Carlos Alemán ◽

Alvaro Meneguzzi ◽

...

Keyword(s):

Zirconium Oxide ◽

Active Sites ◽

Modified Electrodes ◽

Chemical Conversion ◽

Ceramic Materials ◽

Point Of View ◽

Oxide Coatings ◽

Alloying Element ◽

Substrate Nature

Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

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Adsorption and Photocatalytic Reduction of Carbon Dioxide on TiO2

Catalysts ◽

10.3390/catal11010047 ◽

2020 ◽

Vol 11 (1) ◽

pp. 47

Author(s):

Oleksandr Shtyka ◽

Viktar Shatsila ◽

Radoslaw Ciesielski ◽

Adam Kedziora ◽

Waldemar Maniukiewicz ◽

...

Keyword(s):

Photocatalytic Activity ◽

Active Sites ◽

High Efficiency ◽

Chemical Potential ◽

Band Gap Energy ◽

Electromagnetic Spectrum ◽

Reaction Intermediates ◽

Factors Affecting ◽

Phase Reduction ◽

Reduction Of Co2

The photocatalytic activity of TiO2 depends on numerous factors, such as the chemical potential of electrons, charge transport properties, band-gap energy, and concentration of surface-active sites. A lot of research has been dedicated to determining the properties that have the most significant influence on the photocatalytic activity of semiconductors. Here, we demonstrated that the activity of TiO2 in the gas-phase reduction of CO2 is governed mainly by the desorption rate of the reaction intermediates and final products. This indicates that the specific surface area of TiO2 and binding strength of reaction intermediates and products are the main factors affecting the photocatalytic activity of TiO2 in the investigated process. Additionally, it was shown that rutile exhibits higher photocatalytic activity than anatase/rutile mixtures mainly due to its high efficiency in the visible portion of the electromagnetic spectrum.

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Influence of Bio-Oil Phospholipid on the Hydrodeoxygenation Activity of NiMoS/Al2O3 Catalyst

Catalysts ◽

10.3390/catal8100418 ◽

2018 ◽

Vol 8 (10) ◽

pp. 418 ◽

Cited By ~ 4

Author(s):

Muhammad Abdus Salam ◽

Derek Creaser ◽

Prakhar Arora ◽

Stefanie Tamm ◽

Eva Lind Grennfelt ◽

...

Keyword(s):

Active Sites ◽

Batch Reactor ◽

Active Phase ◽

Aluminum Phosphate ◽

Spent Catalyst ◽

Bio Oil ◽

Pore Blockage ◽

Sulfided Catalyst ◽

High Degree

Hydrodeoxygenation (HDO) activity of a typical hydrotreating catalyst, sulfided NiMo/γ-Al2O3 for deoxygenation of a fatty acid has been explored in a batch reactor at 54 bar and 320 °C in the presence of contaminants, like phospholipids, which are known to be present in renewable feeds. Oleic acid was used for the investigation. Freshly sulfided catalyst showed a high degree of deoxygenation activity; products were predominantly composed of alkanes (C17 and C18). Experiments with a major phospholipid showed that activity for C17 was greatly reduced while activity to C18 was not altered significantly in the studied conditions. Characterization of the spent catalyst revealed the formation of aluminum phosphate (AlPO4), which affects the active phase dispersion, blocks the active sites, and causes pore blockage. In addition, choline, formed from the decomposition of phospholipid, partially contributes to the observed deactivation. Furthermore, a direct correlation was observed in the accumulation of coke on the catalyst and the amount of phospholipid introduced in the feed. We therefore propose that the reason for the increased deactivation is due to the dual effects of an irreversible change in phase to aluminum phosphate and the formation of choline.

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Mechanical properties of microwave sintered Si3N4-based ceramics

Science of Sintering ◽

10.2298/sos0203223g ◽

2002 ◽

Vol 34 (3) ◽

pp. 223-229 ◽

Cited By ~ 8

Author(s):

O.I. Getman ◽

V.V. Holoptsev ◽

V.V. Panichkina ◽

I.V. Plotnikov ◽

V.K. Soolshenko

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Bending Strength ◽

Normal Pressure ◽

Ceramic Materials ◽

Particle Sizes ◽

Phase Measurements ◽

Ceramic Samples ◽

Mean Size ◽

The Mean

The mechanical properties and microstructure formation processes in Si3N4+3% AI2O3+5% Y2O3(Yb2O3) ceramic compacts sintered under microwave heating (MWH) and under traditional heating (TH) were investigated. The initial ceramic materials were powder blends of silicon nitride with oxides. The mean powder particle sizes were 0.5-1.0 mim. The content of alfa-phase in the Si3N4 powder was more than 95 %. The samples were sintered at 1800BC in nitrogen at normal pressure, the heating rate in all experiments was 60BC/min. The Vickers hardness (HV), fracture toughness (K1C) and bending strength (on) were determined. The microstructures of fracture surfaces of samples were studied by SEM. Quantitative microstructure analysis was carried out. It was shown that the values of HV and Kic of ceramic samples sintered under MWH at 1800BC rose steadily with the sintering time. This caused an increase in density, which reached maximum as fast as after 30 min of the MWH sintering; the mass loss at that time amounted to 3-4 %. The porosity of sintered samples with an addition of yttria was less than 1 %, that of ytterbia was greater, 2.4 %. For similar values of relative density, the hardness and fracture toughness of ceramic samples produced under MWH were higher as compared with those of samples sintered under TH. The microstructure of samples had the form of elongated grains in a matrix of polyhedral grains of the beta-Si3N4 phase. Measurements showed the mean size of grains in samples produced by MWH to be greater that in samples produced by TH. A larger number of elongated grains were formed. It was concluded that for sintering under MWH of Si3N4-based ceramics the growth of elongated beta-Si3N4 grains and formation of a "reinforced" microstructure were promoted and thereby improved the mechanical properties of such ceramics.

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INCREASING THE STRENGTH AND FROST RESISTANCE OF CERAMIC PRODUCTS AT USING MELASSES BARDS AS PLASTICIZER

Construction Materials and Products ◽

10.34031/2618-7183-2018-1-2-19-29 ◽

2020 ◽

pp. 19-29

Author(s):

S.V. Sverguzova ◽

I. Shayhiev ◽

Tom Otiti ◽

Zh.A. Sapronova

Keyword(s):

Amino Acids ◽

Citric Acid ◽

Frost Resistance ◽

Ceramic Materials ◽

Calcium Citrate ◽

Organic Substances ◽

Ceramic Samples ◽

Natural Clays ◽

Loss Of Mass ◽

Clay Materials

ways of production of ceramic materials with use as the plasticizing additive of the sulphitic and alcohol bards (SAB), the calcium citrate filtrate (CCF) which is liquid withdrawal of production of citric acid in the microbiological way are known. However introduction to raw mix of CoB reduces forming humidity and fall of the formed products insufficiently, and an essential lack of FTsK is the low durability of products on compression with a big volume mass of samples. In work the possibility of use as the plasticizing additive to a clay lot of withdrawal of the spirit industry – melasses bards is investigated. As a part of molasses the remains of amino acids and other organic substances which have the plasticizing effect on clay materials contain. On the example of natural clays of three various fields the plasticizing action melasses bards is proved, and the number of plasticity of the studied clays increases in direct ratio to increase in additive melassny bards in clay raw mix. It is shown that introduction to raw mix melasses bards leads to improvement of appearance of pottery, decrease in jointing, increase in durability for Veselovsky clay for 7%, for the Oryol clay for 67%, for Bessonovskaya – for 23%. Research of the received ceramic samples on frost resistance according to requirements of GOST bards unlike the products which aren’t containing additive bards showed high frost resistance of products with additive melass. Also lowered decrease in durability and loss of mass of the samples containing additive melassny bards is noted

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