Impregnation Of Molybdenum Research Articles

Dual‐mode sensing biopolymer membrane impregnated with molybdenum for ethylene detection and monitoring of fruits

AbstractIn this study, a dual‐mode sensing biopolymer membrane employing chitosan (CS), polyvinyl alcohol (PVA), and ammonium molybdate (AM) was developed for optical and electrochemical detection of ethylene. The biopolymer composite was characterized by X‐ray diffraction (XRD), Fourier transform infra‐red (FTIR), and scanning electron microscopy (SEM).The relationship between ethylene concentration and optical/electrochemical response was investigated. XRD analysis showed enhanced ionic conduction, supported by SEM images showing uniform pore distribution within the synthesized membrane, facilitating effective gas interaction with Molybdenum. The increased FTIR peak intensities with higher amount of molybdenum in the membrane indicates enhanced molecular interactions. Applied to a microelectrode chip, the membrane exhibits a measurable electrochemical response with oxidation peak appearing in cyclic voltammogram as Molybdenum ions undergo reduction upon ethylene exposure. Colorimetric measurements, based on CIELAB values, reveals visible color shift with increasing ethylene concentrations, particularly at 10% molybdenum impregnation. Ionic conductivity and total color difference exhibit parallel variation with ethylene concentrations. X‐ray photoelectron spectroscopy confirms molybdenum oxidation state shift from +6 to +5 in the membrane upon ethylene interaction. The inexpensive colorimetric method enables direct color change visualization in practical applications. The resulting dual‐functional biopolymer membrane shows adaptability and versatility by responding to both optical and electrochemical signals.

Study on the loaded morphology of active metal components in Cu-M@ carbon-based catalysts and their protection against SO2

In this paper, the samples of metal impregnators for activated carbon were prepared by Cu compound with Co, Ni, Zn and Mo compounds, respectively. The loading forms of metal compounds on activated carbon were investigated. With the increase of calcination temperature, the crystal form of the activated carbon metal impregnant sample changes correspondingly. Under the calcination temperature of 200 °C, the sample of copper impregnator completely decomposes into copper oxide with a monoclinic crystal phase structure, and the cobalt impregnator samples decompose from CoCO3 to Co3O4. Its main component is Co3O4, with a cubic phase structure. The metallic zinc compounds decomposed completely into hexagonal zinc oxide crystals with a wurtzite structure. For the solid sample of molybdenum impregnation agent, ammonium molybdate pyrolyzed to remove all water of crystal and part of ammonium ions, and its crystal shape changed from (NH4)6Mo7O24•4H2O to (NH4)2Mo4O13. Meanwhile, the protection performance of metal-impregnated samples against sulfur dioxide was also evaluated. The evaluation results show that the two-component Cu-Ni impregnated sample had the strongest SO2 protection performance under the calcination condition of 150 °C.

Studies of Liquid Fuel Formation from Plastic Waste by Catalytic Cracking Over Modified Natural Clay and Nickel Nanoparticles

Plastics are the dominant part of waste. Recycling is a major challenge beside avoiding of plastic consumption. Development of economic catalysts is a crucial factor to provide cost effective recycling of plastics into fuels. The primary objective of this research is to use pure metallic nanoparticles and modified south Asian clay. These composite catalysts were investigated for the effectiveness and degradation of polymers into liquid fuels and compared their activity with commercially available catalytic material. A series of reactions were conducted in a 25 cm3 autoclave reactor under different conditions such as temperature, catalyst load, addition of active metals, and with nickel nanoparticles. The products distribution for the pyrolysis reactions were determined and compared with commercial kerosene, gasoline and diesel. Clay catalyst gave good liquid yield at 350 °C for low-density polyethylene and post-consumer poly-bags. 10% impregnation of nickel on natural clay gave maximum liquid yield 79.23% for LDPE, while for poly- bags it reached up to 76.01%. The amount of liquid yield was found to increase to 12% and 18.6% for LDPE and poly-bags, respectively on the impregnation of nickel on clay compared to neat clay. It could be demonstrated as well that nickel nanoparticles and molybdenum impregnation on clay give a good yield on liquid fuel. The final products are in the range of gasoline, kerosene and diesel.
 

Effect of molybdenum promoter on performance of high silica MoO3/B-ZSM-5 nanocatalyst in biodiesel production

Biodiesel is a clean and renewable energy. In this study, biodiesel was produced through the esterification of free fatty acid (FFA) with methanol over the high silica B-ZSM-5 nanocatalyst. The parent nanocatalyst was synthesized by hydrothermal technique and the promoter was introduced by a multi-step wet impregnation method. XRD, FT-IR, BET, FE-SEM, EDX, TEM, and NH3-TPD analyzes characterized the textural and acidity properties of the nanocatalysts. The promoter was dispersed uniformly without significant framework destruction. The impregnation of molybdenum decreased the strength of the acid sites and increased the concentration of the acid sites. The morphology of the nanocatalyst was spherical including the high crystallinity, high surface area, and mesoporous structure. The 25% MoO3/B-ZSM-5 nanocatalyst showed the best performance in the esterification of FFA. The optimum operating conditions were 6 h reaction time, temperature of 160 °C, 3%wt catalyst concentration, and methanol/FFA molar ratio of 20:1, which resulted in the highest conversion of FFA (98%). The impregnated nanocatalyst had high stability and reusability through the sequence runs including only 5% conversion drop after six runs. The results confirmed the high potential of the developed nanocatalyst for industrial applications.

Effects of niobium and molybdenum impregnation on adsorption capacity and Fenton catalytic activity of magnetite

Nb and Mo co-incorporation could effectively improve magnetite properties towards higher adsorption and remarkable activity in heterogeneous Fenton process.

Development of new materials for alkaline electrolysers and investigation of the potential electrolysis impact on the electrical grid

This paper discusses development of new materials for alkaline electrolysers and assesses the impact of large penetrations of electrolysis plants on the electrical grid. New electrolyser electrodes were produced by a synthesis method of Nickel electroplated with carbon catalyst consisting of Molybdenum-Resorcinol-Formaldehyde (Mo RF), and carbon aerogel of surface area >700 m 2 /g and pore size of 4 nm, followed by an impregnation of molybdenum as a catalyst before deposition on nickel thus creating Ni–Mo RF electrodes. Another electrode made from Vulcan-Carbon-Platinum powder was used to produce Ni–C–Pt electrodes. The different electrodes were compared by analysis of kinetic reaction measurements using polarisation techniques and electrochemical impedance methods. An experiment was carried out to measure the AC and DC harmonics and the efficiency of the electrical parts of an operational 1 Nm 3 /hr electrolyser. In addition, the power system impact analysis of two Alkaline Electrolysis plants connected to the IEEE30 standard power system model was studied in MATLAB environment.

Interactions between Molybdenum and Activated Carbons on the Preparation of Activated Carbon-Supported Molybdenum Catalysts

The influence of the porous texture and surface chemistry of an activated carbon on the preparation of activated carbon-supported molybdenum catalysts was studied. Activated carbons with various degrees of oxidation were used as supports. Supports and catalysts were characterized by nitrogen adsorption at 77 K, temperature-programmed desorption (TPD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The impregnation with molybdenum produced a reduction of the textural properties. TPD results indicated that there was a transformation of CO2- and CO-evolving oxygen functional groups on the activated carbon as a consequence of the impregnation of molybdenum and that acidic groups were acting as chemical anchorage centers. FTIR and XPS analyses confirmed that interactions were established between molybdenum species and carbonyl and ether surface functional groups. These results indicate that the molybdenum was well distributed and reached the inner porous network of the carbon support.

High-resolution electron microscopy study of phosphorus-containing MoS 2/Al 2O 3 hydrotreating catalysts

A series of sulfided molybdenum catalysts supported on alumina and modified with various amounts of phosphorus, previous or simultaneously to the molybdenum impregnation, has been studied by high resolution transmission electron microscopy. The results show that the addition of phosphorus (P 2O 5 > 4 wt.-%) to the catalysts with low molybdenum content (8 wt.-% MoO 3) promotes the formation of single and double layered MoS 2 when the phosphorus and the molybdenum are impregnated simultaneously. In contrast, the addition of phosphorus previous to the molybdenum impregnation leads to higher stacking of the MoS 2 crystallites and promotes the formation of partially sulfided MoO 3 particles. In catalysts with high molybdenum content (14 wt.-% MoO 3), phosphorus addition prevents the agglomeration of the MoS 2 particles induced by high sulfiding temperature.

Molybdena-alumina interaction chemistry: Effect of preadsorbed sulphate and fluorine anions on the dispersion of molybdenum

On the basis of X-ray photoelectron spectroscopic and temperature-programmed reduction results, molybdena-alumina interaction modes were demonstrated to be strongly modified by the preadsorption of sulphate or fluorine anions. Before calcination, the dispersion of molybdenum was considerably suppressed by the pre-existing anions, suggesting that basic hydroxyl groups on alumina play a decisive role in the initial dispersion of molybdates. On calcination at 823 K, the dispersion of molybdenum was greatly improved. It was found that considerable fractions of the SO 2− 4 and F − anions were eliminated by the impregnation of molybdenum and subsequent calcination at 823 K. The reduction temperature of sulphate anions of alumina was shown to be significantly decreased by the presence of molybdena in the proximity.

Catalytic hydrodesulfurization and hydrodenitrogenation over CoMo on TiO 2ZrO 2V 2O 5

Hydrodesulfurization (HDS) of dibenzothiophene and hydrodenitrogenation (HDN) of aniline over CoMo on TiO 2ZrO 2V 2O 5 catalysts and over CoMo on γ-Al 2O 3 catalysts were investigated and compared in a continuous-flow microreactor at 240–350 °C and 3.55 MPa. HDS and HDN activities on Ti/Zr/V-supported catalysts depended on the amounts and the order of impregnation of molybdenum and cobalt. It was found that Ti/Zr/V-supported catalysts had higher HDS and HDN activities than alumina-supported catalysts. The optimal amounts of CoO and MoO 3 on TiO 2ZrO 2V 2O 5 were much less than on alumina. Moreover, the mutual inhibition of HDS and HDN over Ti/Zr/V-supported catalysts was less pronounced than that over alumina-supported catalysts. The Ti/Zr/V-supported catalyst was also more active than the commercial catalyst, HR-306, in hydrodesulfurization of petroleum feedstocks.

Laterite as a catalyst for the hydrotreatment of heavy Oil. II. Influence of chemical and thermal treatments on the HDS and HDM activity

AbstractEffects of thermal treatment and iron extraction by the dithionate method (DCB) on the pore size distribution of laterite, and influence of iron and molybdenum impregnation on hydrodesulfurization (HDS) and hydrodemetallization (HDM) of natural DAO Morishal feedstock, were investigated. Thermal treatment up to 400°C noticeably improves pore size distribution and surface area. Higher temperatures drastically decrease the specific surface area, although the total pore volume remains constant. Iron extraction of laterite calcined at 550°C decreases HDS activity, but improves HDM activity. On the contrary, iron and molybdenum impregnation noticeably increases HDS activity and does not improve the HDM function.

Contact carbon impregnation of molybdenum and niobium castings

The results are presented of a metallographic study of the surface zone of castings from niobium and molybdenum poured into graphite molds. Differences in the character of carbon diffusion into molybdenum and niobium castings are examined. The characteristics of the diffusion processes investigated are explained in the light of information on the electronic structure of the molybdenum, niobium, and carbon atoms.