CTAB Reverse Micelles as Catalysts for the Oxidation of Ascorbic Acid by K3[Fe(CN)6]

The oxidation of ascorbic acid by K3[Fe(CN)6] was studied in reverse micellar systems composed of CTAB (Cetyltrimethylammonium bromide), and it was found the observed first order (k1(aq) = 5.2×10−5 s−1, k1(rev) = 61.4×10−4 s−1) rate constant in reverse micellar medium is around forty times higher compared to aqueous medium under identical conditions. The rate enhancement (k2(aq) = 0.9×10−5 mole−1.dm3.sec−1, k2(rev) = 1.75×10−3 mole−1.dm3.sec−1) is attributed to the large concentration effect and lower dielectric constant in the reverse micelles. The rate of the reaction increases with increase in W = {[H2O]/[surfactant]} which is explained in terms of ionic strength of the water pool. The effect of surfactant concentration on rate was explained on the basis of Berezin pseudo phase model. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

French Fries-Like Bismuth Oxide: Physicochemical Properties, Electrical Conductivity and Photocatalytic Activity

Bismuth oxide synthesis using hydrothermal method has been conducted. This study aims to examine the effect of the hydrothermal reaction time on product characteristics and photocatalytic activity in degrading methyl orange dye. Bismuth oxide synthesis was initiated by dissolving bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) and Na2SO4 in a distilled water and added NaOH gradually. The solution formed was transferred into a Teflon-lined autoclave and heated at 120 °C with time variations of 8–16 h. The formation of bismuth oxide was indicated by the vibrations of the Bi−O−Bi and Bi−O groups and the crystal structure consisting of a-Bi2O3, β-Bi2O3, and g-Bi2O3. In addition, the highest photocatalytic activity can be examined through several factors, such as: content of Bi−O−Bi and Bi−OH groups, crystal structure, band gap values, morphology, and surface area, acquired as a result of the effect of hydrothermal reaction time. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The Production of Green Diesel Rich Pentadecane (C15) from Catalytic Hydrodeoxygenation of Waste Cooking Oil using Ni/Al2O3-ZrO2 and Ni/SiO2-ZrO2

Hydrodeoxygenation (HDO) is applied in fuel processing technology to convert bio-oils to green diesel with metal-based catalysts. The major challenges to this process are feedstock, catalyst preparation, and the production of oxygen-free diesel fuel. In this study, we aimed to synthesize Ni catalysts supported on silica-zirconia and alumina-zirconia binary oxides and evaluated their catalytic activity for waste cooking oil (WCO) hydrodeoxygenation to green diesel. Ni/Al2O3-ZrO2 and Ni/SiO2-ZrO2 were synthesized by wet-impregnation and hydrodeoxygenation of WCO was done using a modified batch reactor. The catalysts were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDS), and N2 isotherm adsorption-desorption analysis. Gas chromatography - mass spectrometry (GC-MS) analysis showed the formation of hydrocarbon framework n-C15 generated from the use of Ni/Al2O3-ZrO2 with the selectivity of 68.97% after a 2 h reaction. Prolonged reaction into 4 h, decreased the selectivity to 58.69%. Ni/SiO2-ZrO2 catalyst at 2 h showed selectivity of 55.39% to n-C15. Conversely, it was observed that the reaction for 4 h increased selectivity to 65.13%. Overall, Ni/Al2O3-ZrO2 and Ni/SiO2-ZrO2 catalysts produced oxygen-free green diesel range (n-C14-C18) enriched with n-C15 hydrocarbon. Reaction time influenced the selectivity to n-C15 hydrocarbon. Both catalysts showed promising hydrodeoxygenation activity via the hydrodecarboxylation pathway. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Synthesis of Carbide Lime Waste Derived Base Catalyst (KF/CLW-Fe3O4) for Methyl Ester Production: An Optimization Study

In this paper, solid base catalyst KF/CLW-Fe3O4 was prepared from carbide lime waste, primarily calcium hydroxide with tiny amounts of carbonate and; the catalyst was used in the optimization study on the methyl ester production. The new strong base catalyst was synthesized by chemical impregnation. This catalyst was characterized by Hammett indicator analysis, Brunauer, Emmett, and Teller (BET), scanning electron microscope (SEM), X-ray diffraction (XRD) and temperature-programmed desorption (TPD) of carbon dioxide. The catalyst was further used to catalyzed the transesterification reaction to produce methyl ester. Taguchi method was used to assess the impact of catalyst at different intervals of reaction parameters, including reaction time, methanol to oil ratio, and catalyst loading. A mixed level of orthogonal array design with L9, analysis of variance (ANOVA) and signal to noise ratio were used to determine parameters that significantly impact the palm oil transesterification reaction. High methyl ester conversion was attained, and the catalyst can be easily separated and reused. KF/CLW-Fe3O4 has great potential to be used to produce methyl ester because of its high catalytic activity and environmental friendliness. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Superparamagnetic Iron Oxide Decorated Indium Hydroxide Nanocomposite: Synthesis, Characterization and Its Photocatalytic Activity

A simple and scalable liquid-based method was developed to produce a nanocomposite photocatalyst which was comprised of Fe3O4 nanoparticles (4-5 nm) decorated indium hydroxide nanorods (mean width 33 nm and average aspect ratio 2-3). The nanocomposite was produced at 25 ℃ in water via a hydroxide-induced co-precipitation ensued by a cathodic reduction during which the non-magnetic Fe(OH)3 intermediate was reduced to magnetic Fe3O4 at 20 V within 1 h. The incorporation of Fe3O4 nanoparticles served to bestow magnetic recoverability to the photocatalyst and helped enhance visible light absorption simultaneously. Interestingly, the addition of Fe3+ led to the formation of In(OH)3 nanorods rather than the commonly observed nanocubes. In comparison to the In(OH)3 system having a band gap of 4.60 eV), the band gap of the Fe3O4/In(OH)3 nanocomposite produced was determined to be 2.85 eV using the Tauc’s plot method. The effective reduction in band gap is expected to allow better absorption of visible light which in turns should help boost its photocatalytic performance. The Fe3O4/In(OH)3 nanocomposite was structurally characterized using a combination of PXRD, FESEM, EDS, and TEM and its paramagnetic property was proven with a positive mass susceptibility measured to be 1.30´10−5 cm3.g−1. Under visible light, a photocatalytic degradation efficiency of 83% was recorded within 1 hr for the nanocomposite using methylene blue as a dye. The photocatalytically-active Fe3O4/In(OH)3 should have good potential in visible-light driven waste water degradation once further optimized. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Synthesis of Porous N-doped TiO2 by Using Peroxo Sol-Gel Method for Photocatalytic Reduction of Cd(II)

Porous N-doped TiO2 photocatalyst was successfully synthesized by an environmentally friendly peroxo sol-gel method using polyethylene glycol (PEG) as a templating agent. Here, the effect of PEG addition to the aqueous peroxotitanium solutions on the structure, pore properties and photocatalytic activity of the obtained photocatalysts was systematically studied. The prepared photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and Brunauer-Emmett-Teller (BET). It was found that the doping of nitrogen narrows the band gap of TiO2 leading to enhance its visible-light response. The BET analysis shows that the prepared photocatalysts have a typical mesoporous structure with pore sizes of 3–6 nm. The photocatalytic activity of the prepared photocatalysts was evaluated by photocatalytic reduction of Cd(II) in an aqueous solution under visible light irradiation. The results show that porous N-doped TiO2 with the optimal PEG addition had the highest Cd(II) reduction of 85.1% after 2.5 h irradiation in neutral aqueous solution. This significant improvement in photocatalytic activity of the prepared photocatalysts was mainly attributed to the synergistic combination of N doping and porous structure, which could actively increase the catalytic active site of this photocatalysts. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

The Ni Catalyst Supported on the FSP-made Transition Metal (Co, Mn, Cu or Zn) Doped La2O3 Material for the Dry Reforming of Methane

The transition metal (Co, Mn, Cu or Zn) doped La2O3 material was prepared by flame spray pyrolysis (FSP) technique. The 2 wt.% Ni catalyst supported on this material was characterized by XRD, N2 physisorption, TPR, H2 chemisorption and TGA, and evaluated by the dry reforming of methane (DRM). The perovskite structure was certainly formed when either Co or Mn was introduced. The Cu can generate the La2CuO4 spinel phase while the Zn showed a mixed phase of La2O3, ZnO and La(OH)3. The Ni/Co-La2O3 catalyst was more active for the DRM because of high amount of active dual sites of Ni and Co metals dispersed on the catalyst surface. The formation of La2O2CO3 during the reaction can inhibit the coke formation. The cooperation of La2O2CO3 and MnO phases in the Ni/Mn-La2O3 catalyst was promotional effect to decrease carbon deposits on the catalyst surface. The partial substitution of Co for Mn with a small content of Mn can enhance the catalytic activity and the product yield. The Ni/Mn0.05Co0.95-La2O3 catalyst showed the highest CH4 conversion, H2 yield and H2/CO ratio. The Mn inserted into the perovskite structure of LaCoO3 was an important player to change oxygen mobility within the crystal lattice to maintain a high performance of the catalyst. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Preparation of Bi2O3/TiO2–Montmorillonite Nanocomposites and Their Applications to the Photodegradation of Pentachlorophenol

In the past decades, there has been a growing tendency to study the different techniques that can increase the photocatalytic efficiency as well as recyclability of new products “photocatalysts” for water treatment. In this last research the effect of bismuth addition to titanium was investigated. Bi/Ti-pillared montmorillonites have been prepared from natural Algerian bentonite exactly from deposits of Maghnia situated in the west side of the country. These nanocomposites were characterized by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET), scanning electron microscopy (SEM) methods, and Fourier Transformed Infrared (FT-IR). The photocatalytic activities have been tested for the removal of pentaclorophenol (PCP) in water. The effect of preparation conditions, the pH of the solution and photocatalysts concentration, on these activities has been investigated. It was found that the photocatalytic degradation increase by addition of bismuth in pillaring process. The Mont-Bi-Ti is shown to be the best photocatalyst in term of photocatalytic activity. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).