Figure - available from: Applied Organometallic Chemistry
This content is subject to copyright. Terms and conditions apply.
Source publication
A novel N‐doped MoO3@SiC hollow nanosphere has been synthesized through two steps. Due to the first step, N‐doped MoO2@C nanosphere was synthesized using the hydrothermal method and in the second step, Si‐C bonds were formed through the low‐temperature magnesiothermic method and MoO3@SiC hollow nanosphere was produced. The prepared nanostructures w...
Citations
... The insufficiency of the HDS method in removing cyclic compounds has led to the utilization of alternative methods. Aromatic compounds may be removed by extractive desulfurization, [6][7][8] oxidative desulfurization (ODS), [9][10][11][12][13] biological desulfurization (BDS), 14 desulfurization alkylation-based, 15 desulfurization chlorine-based, 16 and adsorption desulfurization (ADS). 17 However, these methods need further investigation. ...
In this study, the adsorption of thiophene compounds (TCs), including thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT), from model fuels was investigated using modified activated carbon (AC). The model fuel, prepared as a single‐solute model at a concentration of 2000 ppm based on a mixture concentration of 3000 ppm, served as the basis for the adsorption experiments. Additionally, an examination of thiophene adsorption from commercial fuels, specifically kerosene, was conducted. Experimental data were used to calculate correlated parameters of adsorption isotherms, kinetic models, and the Fisher factor. The pseudo‐second‐order model demonstrated the best fit to the experimental data. Notably, the adsorbent consisting of 10% Cu ⁺ supported on acid‐washed activated carbon (A1CN10) exhibited the highest adsorption capacity for TCs, achieving removal percentages of 78%, 96%, and 100% for T, BT, and DBT, respectively. Various methods were employed to investigate the physicochemical properties of the adsorbents, including N 2 adsorption–desorption surface analysis (BET), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Furthermore, the regeneration of the adsorbent was studied using two techniques: agitation and ultrasound.
... These methods in a traditional way are also ineffective. Catalytic, photocatalytic, and electrocatalytic processes, ion exchange, and oxidation are the chemical processes used for wastewater treatment [14][15][16][17]. Among these methods, advanced oxidation processes (AOPs) are the well-known and effective methods for the removal of various organic pollutants such as dyes, antibiotics, pesticides, etc. [18][19][20][21][22][23][24]. ...
... The system was saturated with oxygen by air bubbling during stirring. To optimize the photocatalytic reaction, different amounts of graphene catalyst (10,15, and 20 mg) were tested for degradation of TCL at a pH of 2-12. First, all of the samples were stirred for 10 min to reach the equilibrium and then, the removal of TCL was measured in the presence of dissolved oxygen. ...
Wastewater contaminated with antibiotics is a major environmental challenge. The oxidation process is one of the most common and effective ways to remove these pollutants. The use of metal-free, green, and inexpensive catalysts can be a good alternative to metal-containing photocatalysts in environmental applications. We developed here the green synthesis of bio-graphenes by using natural precursors (Xanthan, Chitosan, Boswellia, Tragacanth). The use of these precursors can act as templates to create 3D doped graphene structures with special morphology. Also, this method is a simple method for in situ synthesis of doped graphenes. The elements present in the natural biopolymers (N) and other elements in the natural composition (P, S) are easily placed in the graphene structure and improve the catalytic activity due to the structural defects, surface charges, increased electron transfers, and high absorption. The results have shown that the hollow cubic Chitosan-derived graphene has shown the best performance due to the doping of N, S, and P. The Boswellia-derived graphene shows the highest surface area but a lower catalytic performance, which indicates the more effective role of doping in the catalytic activity. In this mechanism, O2 dissolved in water absorbs onto the positively charged C adjacent to N dopants to create oxygenated radicals, which enables the degradation of antibiotic molecules. Light irradiation increases the amount of radicals and rate of antibiotic removal.
... These methods in 2 a traditional ways are also non-effective. Catalytic, photocatalytic, and electrocatalytic processes, ion exchange, and oxidation are the chemical processes used for wastewater treatment [10][11][12][13]. Among these methods, advanced oxidation processes (AOPs) are the well-known and effective methods for removal of various organic pollutants such as dyes, antibiotics, pesticides, and, etc [14][15][16][17][18][19][20]. ...
Wastewater contaminated with antibiotics is a major environmental challenge. We developed here the green synthesis of bio-graphenes by using natural precursors (Xanthan, Chitosan, Boswellia, Tragacanth). The use of these precursors can act as templates to create 3D doped graphene structures with special morphology. Also, this method is a simple method for in-situ synthesis of doped graphenes. The elements present in the natural polymers (N) and other elements in the natural composition (P, S) are easily placed in the graphene structure and improve the catalytic activity due to the structural defects, surface charges, increased electron transfers, and the high absorption. In this mechanism, O2 dissolved in water absorbs onto the positive charged C in doped graphenes to create oxygenated radicals, which enables the degradation of antibiotic molecules. Light irradiation increases the amounts of radicals and rate of antibiotic removal. The results have shown that the hollow cubic Chitosan-derived graphene has shown the best performance due to the doping of N, S, and P. The Boswellia-derived grapheme shows the highest surface area, but lower catalytic performance, which indicates the more effective role of doping in the catalytic activity. The effect of oxygen and light were also studied to accelerate the degradation process.
... FT-IR spectra of g-SiC, g-SiC/Ag 2 WO 4, g-SiC/Bi 2 WO 6 , and g-SiC/Na 2 WO 4 . [42][43][44][45][46][47] . The high amounts of immobilized tungstates (AWO) on the surface of g-SiC have led to the observation of weak diffractions from 6H-SiC in these composites. ...
We developed here the efficient photocatalysts for the removal of high concentrations of tetracycline under visible light by immobilizing the AWO (A = Ag, Bi, Na) nanocrystals on the surface of siligraphene (g-SiC) nanosheets. The g-SiC/AWO composites was synthesized by magnesiothermic synthesis of g-SiC and sonochemical immobilization of tungstates. These new heterojunctions of g-SiC/tungstates show superior photocatalytic activities in the degradation of high concentrations of tetracycline and 97, 98, and 94% of tetracycline were removed by using low amounts of g-SiC/Ag2WO4, g-SiC/Bi2WO6, and g-SiC/Na2WO4 catalysts, respectively. Based on band structures, the band gaps reduce and the photocatalytic activities were extremely enhanced due to the shortening of electron transfer distance through the Z-scheme mechanism. Also, the graphenic structure of g-SiC is another parameter that was effective in improving photocatalytic performance by increasing the electron transfer and decreasing the rate of electron–hole recombination. Furthermore, the π back-bonding of g-SiC with metal atoms increases the electron–hole separation to enhance the photocatalytic activity. Interestingly, g-SiC composites (g-SiC/AWO) showed much higher photocatalytic properties compared to graphene composites (gr/AWO) and can remove the tetracycline even at dark by producing the oxygenated radicals via adsorption of oxygen on the positive charge of Si atoms in siligraphene structure.
... A wide variety of efficient catalysts were introduced for the oxidative desulfurization of fuels [13][14][15][16][17][18][19][20]. Catalysts designed based on metal oxides such as molybdenum, tungsten, titanium, and so forth are active and effective species in sulfur removal [21][22][23][24][25][26][27][28][29][30][31][32]. In these catalysts, porous supports are generally exploited to increase the surface area and stability of the catalyst. ...
... In these catalysts, porous supports are generally exploited to increase the surface area and stability of the catalyst. Silica, alumina, and carbon-based materials are the common supports to immobilize the active metal oxide catalysts [20][21][22][23][24][25][26][27][28][29][30][31][32]. Designing properly supported catalysts can increase the accessible active sites and enhance the catalytic performance. ...
W-doped graphene has been successfully synthesized here using Arabic gum as a natural precursor,
which leads to the in-situ embedding of tungsten species into the graphene matrix. In W defects, tungsten bonds with adjacent carbons and forms carbide. The catalytic efficiency of this catalyst was tested in
the oxidative desulfurization of model fuel using H2O2 as a green oxidant. This W-doping enhances sulfur
removal due to the active WC species and increases the surface area and structural defects which are
effective on the adsorption of substrate on the surface of catalyst. Catalyst was also modified with molybdenum oxide to increase the rate of reaction. The result shows that the modified MoO3 catalyst show
higher catalytic activity (99.6%) at a lower time (80 min) compared to W-doped graphene (98.6% after
120 min). This catalyst can be introduced as an attractive ODS catalyst due to the ability to remove high
sulfur concenteration (2000 ppm) with a low amount of catalyst (5 mg) compared to similar reports. The
magnetic form of this catalyst was also synthesized by adding Fe3O4 nanoparticles into the graphene
structure in order to separate the catalyst more easily. Comparable catalytic activity and higher durability
are the advantages that make this magnetic composite a suitable desulfurization catalyst as an effective
alternative for the desulfurization of model fuel.
... The antioxidant solutions were prepared by dissolving each antioxidant in a certain volume of ethanol based on the results of the electrochemical experiments. A paper sample containing iron gall was immersed in the antioxidant solutions for 10 s and then air dried [31] ( Fig. 1 d). To study the effect of a ternary mixture of antioxidants, antioxidants with equal proportions were used. ...
... Nevertheless, in this process they are less explored. [16,[23][24][25][26][27][28][29] A series of oxidants have been studied in ODS, like H 2 O 2 and tert-butyl hydroperoxide (TBHP). TBHP is attracting a lot of interest, since it is thermodynamically stable till 353 K and the described works were performed at 323-353 K to maintain the oxidant in an active form, and to circumvent the problems described before for H 2 O 2 . ...
... Most of the described works use supported catalysts and showed that without the presence of the metals the supports did not exhibit any catalytic activity. [29][30][31] It is described that Mo-containing systems showed around 95 % selectivity for diphenyl sulfone and nearly 90 % conversion of the diphenyl sulfide substrate. [29] It is very important to have acidic species to undergo this type of reaction. ...
... [29][30][31] It is described that Mo-containing systems showed around 95 % selectivity for diphenyl sulfone and nearly 90 % conversion of the diphenyl sulfide substrate. [29] It is very important to have acidic species to undergo this type of reaction. These species can be from Brønsted-Lowry or others corresponding to Lewis species. ...
Gathering clean energy from fuel feedstocks is of paramount significance in environmental science. In this area, desulfurization provides a valuable contribution by eliminating sulfur compounds from fuel feedstocks to ensure they can be used without emission of toxic sulfur oxides. MoO3 nanoparticles have been hydrothermally synthesized and used as efficient catalyst in the oxidative desulfurization (ODS) of methylphenyl and diphenyl sulfide using TBHP or H2O2 as oxidant. The catalyst showed an enhancement in the ODS process of the two substrates revealing influence on the reaction rate and product selectivity. Temperature and solvent influenced the conversion for the desired product as well. The activity of the catalyst was stable for at least 3 continuous catalytic cycles. Catalytic performance of MoO3 nanomaterial was comparable or better than other catalysts reported in the literature in terms of the sulfoxide or sulfone yield.
... However, the application of these metal oxides is limited due to their low surface areas. To overcome this disadvantage, metal oxides are usually used in the form of immobilized catalysts on porous supports such as silica, alumina, carbon, and silicon carbide [17][18][19][20][21][22]. Immobilization of catalysts is an effective way to increase the accessible active sites by increasing the surface area and homogenous distribution of metal oxide. ...
We developed here a green procedure for the synthesis of novel N–doped bio-graphenes from Arabic gum as a natural source by using different N-dopants (urea, hexamethyleneteramine, and ethylenediamine) and Gelatin as a carbon source containing N species. The effect of these dopants on the type of nitrogen species, nitrogen contents, and surface structure of graphene catalysts was investigated on their catalytic properties for oxidative removal of sulfur compounds in fuel oil. All of doped graphenes show the pyridinic and pyrrolic nitrogen species, while the graphene doped with hexamethylenetetramine shows the highest amount of nitrogen with some content of amine group as well as pyridinc-N and pyrrolic-N. This N-doped graphene indicates the highest catalytic activity due to the type of nitrogen species, higher nitrogen content, and higher surface area. The resulting immobilized catalysts with MoO3 also show the similar trend in catalytic activities. Nitrogen doping increase the electron density of peroxo groups by donating electrons to Mo-centers which enhance the catalytic activity by decreasing the oxidation barrier.
... However, the application of these metal oxides is limited due to their low surface areas. To overcome this disadvantage, metal oxides are usually used in the form of immobilized catalysts on porous supports such as silica, alumina, carbon, and silicon carbide [17][18][19][20][21][22]. Immobilization of catalysts is an effective way to increase the accessible active sites by increasing the surface area and homogenous distribution of metal oxide. ...
In this research, the novel nano-filled fluoroelastomer (FKM) composites with excellent thermal and mechanical properties were prepared using the Siligraphene (graphene-like SiC), g-C3N4, and Siligraphene/g-C3N4 composites to improve the thermal and mechanical stability of FKM. The nanocomposites were exposed to heat aging test and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), dynamic mechanical analysis (DMA), and tensile test. Results show that Siligraphene, g-C3N4, and Siligraphene/g-C3N4 improved the tensile properties of FKM before and after exposure to the aging test. Si and N dopants in the graphenic structure of Siligraphene and g-C3N4 nanofillers are the effective parameter to reinforce the properties of nanocomposites. In general, these nanofillers provided better adhesion with FKM matrix. It can be justified by a better distribution of filler and higher interaction between filler and FKM which form the cellulation structure that can improve the mechanical properties and prevent the rubber decomposition at high temperatures by resisting molecular mobility.
... Among these materials, silicon carbide (SiC), due to its unique properties such as high surface area, high chemical, mechanical and thermal stability is an appropriate candidate for various catalytic process [20][21][22][23][24][25][26][27][28]. Silicon carbide is built up by a covalently bonded tetrahedral unit in such a way that each carbon atoms is surrounded by four silicon atoms or inversely one carbon atom is surrounded by four silicon atoms, in the form of CSi 4 or SiC 4. The four bonds have covalent character with a difference in electronegativity between the Si and C atoms which causes a small positive charge on the Si atom. ...
... In a typical run, various model fuels such as DBT, BT, and TH with different sulfur concentration (100, 300, 500, 700, and 1000 ppm) were prepared by dissolving them in n-octane. The ODS reaction was done in a 25 mL flask equipped with a magnetic stirrer and a water bath at various temperature (25,40,50, and 65 C). First, a certain amount of catalyst (10À30 mg), 2 mL of model fuel, 1 mL of acetonitrile as an extractive solvent, and ndodecane as an internal standard were mixed together by stirring in a given temperature. ...
... Effect of temperature In the desulfurization system, the temperature is an important parameter. Fig. 8 exhibits the effect of different temperature (25,40,55, and 65 C) on the oxidative desulfurization of model fuel (500 ppm(S) of DBT). The result indicates that by increasing of the temperature clearly enhances the catalytic activity of N-WO 3 -NH 2 -SiO 2 @SiC. ...
s
A novel N-doped SiO2@SiC core shell has been synthesized and functionalized with amino groups. Then, amino hybrid of tungsten oxide was supported on the surface of functionalized SiO2@SiC core shell by immobilization of tungsten complex and coordination of ethylenediamine to tungsten centers. Then, the catalytic activities of prepared hybrids were investigated in oxidative desulfurization of model fuels. To evaluate the role of silicon carbide support, silica nanospheres also were functionalized and its catalytic performance was compared. The results indicate that the SiC catalyst shows higher catalytic activity (99.9%, 160 min) compared to the SiO2 analogue (61%, 160 min).
