Oxidative Desulfurization Of Dibenzothiophene Research Articles

Oxidative desulfurization of dibenzothiophene over V-Mo co-doped akaganeite

In this paper, V-Mo co-doped akaganeite (β-FeOOH) was prepared by one-pot hydrothermal method and the oxidative desulfurization (ODS) of dibenzothiophene over the catalyst was carefully investigated. 0.07g (ca. 0.35wt.% of model oil) of catalyst induced 100% of DBT removal in 60min with a O/S of 20:1 under 60 °C for the model oils with any of the sulfur contents, 100 ppm, 500ppm, or 1000 ppm. Moreover, the DBT removal after recycling 4 times is still 100% and it only declines to 98.04% in the fifth cycle, which indicates that the catalyst has a good stability and recycling performance. Doping V species in Mo doped β-FeOOH not only initiates a micro-variation in catalyst structure and the resultant more active •OH species but also forms a more stable structure of the catalyst, enabling the catalyst to exhibit a higher ODS reaction rate and a better reusability. The GC-MS analyses demonstrated that the DBT was converted to DBTO2 by two steps: (1) DBT→ DBTO; (2) DBTO→ DBTO2, and the former is the rate-limiting step.

A novel MOF-808 derived material for oxidative desulfurization: the synergistic effect of hydrophobicity and electron transfer.

A functionalized modified metal-organic framework material, T-MOF-808, was synthesized through hydrophobic modification with tetraethyl orthosilicate (TEOS) and chlorotrimethylsilane (TMCS). Then a supported oxidative desulfurization catalyst, [C12Py]3(NH4)3Mo7O24/T-MOF-808(s), was prepared by using a heteropoly acid ionic liquid as the active component. The prepared samples were characterized using FT-IR, XRD, SEM, TEM, XPS, etc. [C12Py]3(NH4)3Mo7O24/T-MOF-808(s) was used in the oxidative desulfurization of dibenzothiophene (DBT). At the same time, the effects of different loadings of the active component, oxygen sulfur ratios, reaction temperatures, and reaction time were also investigated. [C12Py]3(NH4)3Mo7O24/T-MOF-808-15%(s) could oxidize 100% of DBT in 40 min at 60 °C. Significantly, the catalyst exhibited no discernible decline in catalytic activity after 14 runs. In addition, the efficiency of sulfur removal was 85.76% in actual diesel oil. It was found that the cooperative impact of hydrophobic modification and electron transfer makes an important contribution to the high activity. The hydrophobic modification provides a novel approach for using MOF materials in the oxidative desulfurization process.

Controllable Synthesis of Titanium Silicon Molecular Zeolite Nanosheet with Short b-Axis Thickness and Application in Oxidative Desulfurization.

Titanium silicon molecular zeolite (TS-1) plays an important role in catalytic reactions due to its unique nanostructure. The straight channel on TS-1 was parallel to the orientation of the short b-axis and directly exposed to the aperture of the 10-member ring with a diameter of 0.54 nm × 0.56 nm. This structure could effectively reduce the diffuse restriction of bulk organic compounds during the oxidative desulfurization process. As a kind of cationic polymer electrolyte, polydimethyldiallyl ammonium chloride (PDDA) contains continuous [C8H16N+Cl-] chain segments, in which the Cl- could function as an effective structure-directing agent in the synthesis of nanomaterials. The chain of PDDA could adequately interact with the [0 1 0] plane in the preparation process of zeolite, and then the TS-1 nanosheet with short b-axis thickness (6 nm) could be obtained. The pore structure of the TS-1 nanosheet is controlled by regulating the content of PDDA. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 physical adsorption analysis, infrared absorption spectrum and ultraviolet-visible spectrum were used to determine the TS-1. The thinner nanosheets exhibit excellent catalytic performance in oxidative desulfurization of dibenzothiophene (DBT), in which the removal rate could remain at 100% after three recycles. Here, the TS-1 nanosheet with short b-axis thickness has a promising future in catalytic reactions.

The Green Preparation of Mesoporous WO3/SiO2 and Its Application in Oxidative Desulfurization

Recently, supported WO3-based catalysts have been widely used in oxidative desulfurization (ODS) due to their advantages of easy separation, high activity, and being environment-friendly. In this work, supported mesoporous WO3/SiO2 catalysts have been prepared using an incipient-wetness impregnation method with agricultural waste rice husks as both a silicon source and mesoporous template, and phosphotungstic acid as a tungsten source. The effects of different calcination temperatures and WO3 loadings on the ODS performance of samples are studied, and the appropriate calcination temperature and WO3 loading are 923 K and 15.0 wt.%, respectively. The relevant characterization results show that, compared with pure WO3, the specific surface area and mesopore volume of WO3/SiO2 samples are greatly increased. Due to (a) high WO3 loading, (b) high specific surface area, and (c) nanoscale WO3 grains uniformly dispersed on the surface of the mesoporous SiO2 carrier, active sites of WO3/SiO2 catalysts are greatly increased, and their catalytic activities are improved. After the sixth and eighth runs in the ODS of dibenzothiophene and 4,6-dimethyldibenzothiophene, respectively, the WO3/SiO2 catalyst still maintains high catalytic activity (>99.0%) despite the presence of a partial loss of WO3. In addition, with the aid of the UV-Vis technique, the tungsten-peroxo species, the active intermediates in the ODS reaction catalyzed by the WO3/SiO2 catalyst, are captured. Finally, a possible mechanism for the ODS of bulky organic sulfides using the WO3/SiO2 catalyst is proposed.

Development and optimization of a sustainable polyoxometalate-kaolinite-based catalyst for efficient desulfurization of model and real fuel using Box-Behnken design.

The oxidative desulfurization of dibenzothiophene in model and real fuel has been investigated by developing an environmentally sustainable catalyst H4SiW12O40@f-kaolinite. The catalyst was synthesized by modifying kaolinite clay with (3-aminopropyl)triethoxysilane (f-kaolinite) followed by immobilizing silicotungstic acid hydrate (H4SiW12O40) onto its surface. The successful synthesis of the catalyst was characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, UV-visible spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The influence of variables i.e., catalyst dosage, temperature, and oxidant concentration on the conversion of dibenzothiophene was optimized by Box-Behnken design. The highest sulfur reduction (from 1000 to 78.3 ppm, with a conversion rate of 92.17%) was achieved at 70 °C, using a catalyst dosage of 70 mg and 8 mL of H2O2 in a model fuel. ANOVA analysis indicated that the quadratic model (R 2 = 0.99) was well-fitted for dibenzothiophene conversion, with a p-value of 0.2302 suggesting no statistically significant lack of fit compared to pure error. Furthermore, the H4SiW12O40@f-kaolinite demonstrated a reduction of dibenzothiophene concentration from 354 ppm to 224 ppm in a real fuel oil sample. The heterogeneous nanocatalyst showed remarkable stability, maintaining its elemental structure after five cycles without significant efficiency loss, promoting environmental sustainability.

Oxidative desulfurization of model fuel using a NiO-MoO3 catalyst supported by activated carbon: Optimization study

In this study, oxidative desulfurization of dibenzothiophene (DBT) with an H2O2-acetic acid system whereas the catalyst used is molybdenum oxide supported on activated carbon (AC). The effect of loading nickel oxide as a promoter as well as the impact of catalyst dosage and the initial sulfur concentration were investigated. The ranges for these parameters are catalyst dosage (0.5–1.5) g, nickel loading (2–6) wt.% and initial sulfur concentration (400–800) ppm. A Response Surface Methodology (RSM) combined with Box-Behnken design (BBD) was utilized to evaluate the impacts of studied variables; the evaluation consists of the level of order significance of each factor, the interaction effects of parameters was analyzed with Analysis of variance (ANOVA) and determine the optimum conditions for oxidative desulfurization (ODS). Results showed that sulfur removal efficiency from model fuel ranged between 23 and 71%, and these results were fitted with a second-order polynomial model with a high correlation coefficient R2 (0.9719). The optimal condition for DBT oxidation is 0.5 g. Ni wt. 6% and 700 ppm for catalyst dosage, nickel loading, and initial sulfur concentration respectively.

Process Optimization for Catalytic Oxidation of Dibenzothiophene over UiO-66-NH2 by Using a Response Surface Methodology.

This research investigates the catalytic performance of a metal–organic framework (MOF) with a functionalized ligand—UiO-66-NH2—in the oxidative desulfurization of dibenzothiophene (DBT) in n-dodecane as a model fuel mixture (MFM). The solvothermally prepared catalyst was characterized by XRD, FTIR, 1H NMR, SEM, TGA, and MP-AES analyses. A response surface methodology was employed for the experiment design and variable optimization using central composite design (CCD). The effects of reaction conditions on DBT removal efficiency, including temperature (X1), oxidant agent over sulfur (O/S) mass ratio (X2), and catalyst over sulfur (C/S) mass ratio (X3), were assessed. Optimal process conditions for sulfur removal were obtained when the temperature, O/S mass ratio, and C/S mass ratio were 72.6 °C, 1.62 mg/mg, and 12.1 mg/mg, respectively. Under these conditions, 89.7% of DBT was removed from the reaction mixture with a composite desirability score of 0.938. From the results, the temperature has the most significant effect on the oxidative desulfurization reaction. The model F values gave evidence that the quadratic model was well-fitted. The reusability of the MOF catalyst in the ODS reaction was tested and demonstrated a gradual loss of activity over four runs.

Simple and Green Preparation of ZnO Blended with Highly Magnetic Silica Sand from Parangtritis Beach as Catalyst for Oxidative Desulfurization of Dibenzothiophene

Simple and green preparation of ZnO blended with Parangtritis beach sand (BS) catalysts for oxidative desulfurization of dibenzothiophene (ODS-DBT) has been conducted. The ZnO-BS catalysts were prepared by blending ZnO with beach sand under a weight ratio of 1:1, 1:2, and 1:4, and then heated by microwave (MW) at 540 watts for 30 min, resulting in BS-MW, ZnO-MW, ZnO-BS-1-MW, ZnO-BS-2-MW, and ZnO-BS-4-MW, respectively. As a comparison, the ZnO-BS-1 was also heated by oven at 100 °C for 30 min produced ZnO-BS-1-OV. Each product was characterized by XRF, XRD, FTIR, acidity test by NH3 vapor adsorption, SAA, SEM-EDX, TEM, and magneticity test by an external magnetic field. Furthermore, each material was applied for ODS-DBT, and its product was analyzed by UV-Vis spectrophotometer and FTIR. The results showed that ZnO-BS-1-OV had the highest acidity of 2.3486 mmol/g and produced the highest DBT removal efficiency through the ODS reaction of 81.59%. The use of catalysts in ODS-DBT does not affect the main structure of the treated fuel. Therefore, the combination of ZnO with BS can provide good performance in ODS activity and facilitate the separation of catalysts after the reaction due to its magnetic iron oxide content.

Oxidative desulfurization of dibenzothiophene over highly dispersed Mo-doped graphitic carbon nitride

Oxidative desulfurization of dibenzothiophene over highly dispersed Mo-doped graphitic carbon nitride

ZnO-Activated Carbon Blended as a Catalyst for Oxidative Desulfurization of Dibenzothiophene

The problem of sulfur content in heavy oil is a challenge for researchers to meet the needs of environmentally friendly fuels. The catalyst preparation plays an important role in the desulfurization process. The synthesis of ZnO-activated carbon as a catalyst and its activity in oxidative desulfurization (ODS) reaction has been successfully carried out. In this work, the ZnO and activated carbon (AC) were blended by a solid-solid reaction. The ZnO, AC, and ZnO-AC were then characterized using acidity test with pyridine vapor adsorption, Fourier Transform Infra-Red (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), and Surface Area Analyzer (SAA). ODS of dibenzothiophene (DBT) reaction was performed by using H2O2 under variation of the reaction time (30, 60, 120, and 150 min) for the ZnO-AC catalyst. The efficiency of ODS-DBT was analyzed by a UV-Visible spectrophotometer. The XRD analysis result showed that ZnO-AC blended displays new crystal peaks of Zn in the AC diffractogram. The surface area (734.351 m2/g) and acidity (4.8780 mmol/g) of ZnO-AC were higher than ZnO and AC themselves. ZnO-AC produced the highest efficiency of ODS-DBT which was 93.83% in the reaction time of 120 min. Therefore, the simple procedure of this physical blending was proved effective to homogenize between ZnO and AC into ZnO-AC so that it has good physicochemical properties as an ODS-DBT 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).

Oxidative desulfurization of dibenzothiophene and simultaneous adsorption of products on BiOBr-C3N4/MCM-41 visible-light-driven core–shell nano photocatalyst

In this study, different amounts of BiOBr (x = 0, 5, 10, 15 wt%) and 5% wt. of g-C3N4 were loaded on MCM-41 as core for photo oxidation of DBT and simultaneous adsorption of oxidation products. Among studied photocatalysts, the BiOBr-C3N4/MCM-41 photocatalyst with 10% wt. of BiOBr indicated the highest activity so that this sample reduced DBT concentration to the lowest value of C/C0 = 0.08 after 150 min irradiation of visible light. The characterization of the as prepared photocatalysts by XRD, FESEM, TEM, FTIR, BET-BJH, UV–Vis DRS, and PL analyses revealed that this achievement was due to the highest amount of structural defects and the strongest interaction between BiOBr-C3N4 shell and MCM-41 core in this sample. Moreover, this sample indicated the lowest recombination rate of charge carriers, the narrowest band gap, and high porosity that enhanced the photocatalytic efficiency. However, this sample lost 18% of initial activity after four successive cycles of photo oxidation-adsorption that based on FTIR and BET-BJH was because of plugging of pores by DBT sulfones.

Oxidative desulfurization of dibenzothiophene by magnetically recoverable polyoxometalate-based nanocatalyst: Optimization by response surface methodology

Abstract This research investigates the catalytic activity of a new core-shell structured nanocatalyst, which was prepared by surface modification of magnetic silica nanoparticles with Keplerate nano-porous molybdenum oxide-based polyoxometalate ({Mo132}), in oxidative desulfurization (ODS) of dibenzothiophene (DBT) in n-octane as simulated fuel (SF). The characterization of the as-prepared catalyst was performed by several methods including XRD, FTIR, VSM, TEM, HRTEM, SEM/EDS, HAADF-STEM EDX line scan, ICP-OES, and CHNS analysis. The optimization process and design of experiments were performed by response surface method with the principles of central composite design (CCD). The effects of reaction conditions including temperature (X1), O/S molar ratio (X2), and concentration of the catalyst (X3) were assessed on DBT removal efficiency. The statistical results showed that temperature was the most effective parameter in the process. Meanwhile, optimal conditions for DBT removal were attained when the dosage of the catalyst, O/S molar ratio, and temperature were 0.0074 g cat. g-1 SF, 20.7, and 58 oC, respectively. Moreover, a sulfur removal of 99.94% was obtained for SF using the prepared catalyst within 30 min under the optimal reaction conditions. The recovery of catalysts from the reaction medium was done with a magnet and the performance of the recovered catalyst showed no loss in activity after four test runs.

Sequential Post-Synthetic Modification and Evaluation of Catalytic Activity of Hierarchically Porous Sulfated Geopolymer in the Oxidative Desulfurization of Dibenzothiophene

A novel sulfated hierarchically porous geopolymer catalyst for the oxidation of dibenzothiophene was prepared through sequential treatment with desilication, ion-exchange and sulfation techniques. Desilication and ion-exchange treatments were aimed at the creation of hierarchical porosity and controlling the surface area of the geopolymer, while sulfation treatment was primarily done to enhance the acidity of the hierarchically porous geopolymer. The properties of the catalyst obtained after the modifications was studied by BET, NH3-TPD, SEM, TEM, XRD, FTIR and XRF analyses. As a result of the proposed sequential treatment, the activity of the geopolymer towards the oxidation of dibenzothiophene was profoundly increased and reflected in the enhanced conversion from 14 to 85%. A plausible electronic mechanism proposed for the reaction accentuated that the reaction might take place in two stages: the formation of sulfated geopolymer peroxo complex as the active catalyst and nucleophilic attack by dibenzothiophene over the peroxo complex to form the product, both were elaborated with suitable kinetic model. The interaction between dibenzothiophene and peroxo complex was considered to be of primary concern, based on which, Langmuir–Hinshelwood kinetic model was developed. Effective regeneration upto three cycles emphasized its potential to be exploited as an efficient catalyst for oxidative desulfurization.

Oxidative desulfurization of dibenzothiophene via layered graphitic carbon nitride-coordinated transition metal as a catalyst

In this study, graphitic carbon nitride (g-C3N4) has been synthesized. The cobalt-doped (CoO/g-C3N4) samples prepared by the impregnation method and their catalytic property were investigated on the ODS process.

Oxidative Desulfurization of Dibenzothiophene Using Cobalt (II) Complexes with Substituted Salen-Type Ligands as Catalysts in Model Fuel Oil

Three cobalt(II)-salen complexes (CoL1, CoL2 and CoL3) were synthesized via the reaction of the three tetradentate ligands as N,N′-ethylenebis(salicylimine) L1, N,N′-ethylenebis(3-tert-butylsalicylimine) L2 and N,N′-ethylenebis(3,5-di-tert-butylsalicylimine) L3, with a stoichiometric amount of cobalt(II) acetate tetrahydrate, respectively. All the three complexes were studied as oxidative desulfurization catalyst on dibenzothiophene taken in model fuel oil n-dodecane. The acetonitrile used as an extracting solvent and H2O2 as an oxidant. Comparatively CoL3 proved to be the best catalyst which showed the 76% DBT removal at the optimized conditions. The nth-order kinetic model is the best way to represent oxidation kinetics of complexes. This cobalt(II) Schiffs base complexes were studied as catalyst for oxidative desulfurization of dibenzothiphene (DBT) taken as model sulphur compounds in fuel model oil (n-dodecane) using H2O2 as oxidant and acetonitrile as extracting solvent for DBT sulfone in a batch experiment.

Oxidative Desulfurization of DBT with H2O2 over 3DOM H3PW12O40/Al2O3 Catalyst

A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method. Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst. Moreover, Keggin-type HPW was highly dispersed in the Al2O3 framework, which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results. The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide. It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h, which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst. The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure. Furthermore, the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs, which could be easily recovered from the model fuel.

Ionothermal Synthesis of Metal Oxide-Based Nanocatalysts and Their Application towards the Oxidative Desulfurization of Dibenzothiophene

Herein, different types of metal-containing ionic liquid (IL) complexes and various metal oxide-based nanocatalysts have been successfully prepared (from ionic liquids) and applied for the oxidative desulfurization (ODS) of dibenzothiophene (DBT). The ILs complexes are comprised of N,N′-dialkylimidazolium salts of the type [RMIM-Cl]2[MCln], where [RMIM+] = 1 alkyl-3-methylimidazolium and M = Mn(II)/Fe(II)/Ni(II)/Co(II). These complexes were prepared using an easy synthetic route by refluxing the methanolic solutions of imidazolium chloride and metal chlorides under facile conditions. The as-prepared complexes were further used as precursors during the ionothermal and chemical synthesis of various metal oxide-based nanocatalysts. The resulting ILs salts and metal oxides NPs have been characterized by FT-IR, TGA, XRD, SEM, and TEM analysis. The results indicate that thermal and chemical treatment of ILs based precursor has produced different phases of metal oxide NPs. The calcination produced α-Fe2O3, Mn3O4, and Co3O4, NPs, whereas the chemical treatment of the ILs salts have led to the production of Fe3O4, Mn2O3, and α-Co(OH)2. All the as-prepared salts and metal oxide-based nanocatalysts were used as catalysts towards ODS of dibenzothiophene. The oxidation of dibenzothiophene was performed at atmospheric conditions using hydrogen peroxide as the oxygen donor. Among various catalysts, the thermally obtained metal oxide NPs such as α-Fe2O3, Mn3O4, and Co3O4, have demonstrated relatively superior catalytic activities compared to the other materials. For example, among these nanocatalysts, α-Fe2O3 has exhibited a maximum conversion (∼99%) of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2).

Reverse microemulsion synthesis of polyoxometalate-based heterogeneous hybrid catalysts for oxidative desulfurization

Keggin-type heteropoly acids are known as active catalysts for oxidative desulfurization of refractory sulfur compounds from fuels. In this work, cesium salts of phosphotungstic acid (HPW) were synthesized based on three different methods: co-precipitation, reversed emulsion, and reversed microemulsion. For reversed microemulsion procedure, the effect of adding order of cesium ion or phosphotungstic acid in the micelle aggregation of sodium dodecyl sulfate (SDS) surfactant was investigated to synthesize different particle sizes of heterogeneous HPW. Obtained products were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and N2 physical adsorption–desorption techniques. It was observed that all materials obtained via reversed microemulsion method are in organic–inorganic hybrid form which origin from the attachment of SDS to cesium salts of HPW. Oxidative desulfurization of dibenzothiophene from hexane was performed to investigate the activity of the prepared catalysts. The best catalytic activity was achieved by the new organic–inorganic hybrid materials obtained via the reversed microemulsion method.

Keggin polyoxometalates encapsulated in molybdenum-iron-type Keplerate nanoball as efficient and cost-effective catalysts in the oxidative desulfurization of sulfides

In this work, the catalytic activity of core-shell-type polyoxometalate (POM) composites, comprised from Keggin POMs encapsulated in Mo72Fe30 Keplerate, in the oxidation of various sulfides into corresponding sulfoxides or sulfones and oxidative desulfurization of dibenzothiophene with hydrogen peroxide are investigated. From the results, the catalytic activity of these Keggins encapsulated in Keplerate are better than parent ones and among them BW12 ⊂ Mo72Fe30 showed the best results. The operationally simple oxidation reactions at room temperature, high to excellent yields and chemoselectivity, short reaction times, and the use of H2O2 as oxidant are some of the other advantages in this catalytic system. Also, the synergistic effect of Keggin POMs and Mo72Fe30 Keplarate has been confirmed.

Molybdenum (VI)‐functionalized UiO‐66 provides an efficient heterogeneous nanocatalyst in oxidation reactions

A novel heterogeneous nanocatalyst was established by supporting molybdenum (VI) on Zr6 nodes in the structure of the well‐known UiO‐66 metal–organic framework (MOF). The structure of the UiO‐66 before and after Mo (VI) immobilization was confirmed with XRD, DR‐FTIR and UV–vis spectroscopy, and the presence and amount of Mo (VI) was identified by X‐ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy. TEM imaging confirmed the absence of Mo clusters on the MOF surface, while SEM confirmed that the appearance of the MOF has not changed upon immobilizing the Mo (VI) catalyst. BET adsorption measurements were used to confirm the porosity of the catalyst. The catalytic activity of this heterogeneous catalyst was investigated in oxidation of sulfides with H2O2 in acetonitrile and oxidative desulfurization of dibenzothiophene. Easy work up, convenient and steady reuse and high activity and selectivity are prominent properties of this new hybrid material.