Desulfurization Of Thiophene Research Articles

Photocatalytic Desulfurization of Thiophene with Chevrel Phase Ni2Mo6S8 Synthesized by SHS.

The Chevrel phase compounds Cu4Mo6S8, Ni2Mo6S8, and Fe2Mo6S8, synthesized by self-propagating high temperature synthesis, were evaluated as photocatalysts for visible light photocatalytic desulfurization. Investigations began with reflectance measurements from which absorbance spectra were calculated using the Kubelka-Munk transformation. The absorbance data was then used to create Tauc plots to find the direct and indirect bandgaps of the Chevrel phase compounds. Bandgaps were found to be no more than the 1.74 eV for Ni2Mo6S8, so it was selected for further study because this bandgap suggests it will use the sun's emission spectrum better than the other materials studied here. Photocatalytic desulfurization experiments studied the concentration of thiophene mixed into n-octane with and without exposure to Ni2Mo6S8 with and without light exposure because of the relative difficulty of removing thiophenes from liquid fossil fuels by the industry standard hydrodesulfurization process. Ultraviolet-visible spectroscopy was used to analyze chemical changes in the thiophene-octane solution. Spectroscopic results demonstrate that the thiophene was effectively removed by exposure to Ni2Mo6S8 and visible light together but not by exposure to Ni2Mo6S8 or visible light alone. Multiple tests with the same Ni2Mo6S8 sample demonstrate that the material is reusable as a catalyst for photocatalytic desulfurization. The proposed mechanism results in the release of SO x species, which may be controlled and captured if separated from fossil fuels in bulk during industrial processing in contrast to their uncontrolled release as vehicle fuel exhaust. Controlled generation and collection of these species can allow for further processing into elemental sulfur in the same way that H2S released by standard hydrodesulfurization is processed into elemental S.

Novel MnCo2O4/YVO4 heterostructure for promoting photocatalytic oxidative desulfurization of thiophene under visible light

In this work, for the first time, the photocatalytic oxidative desulfurizing of thiophene through exposure to visible light was performed on mesoporous MnCo2O4/YVO4 heterojunctions. Mesoporous YVO4 nanocrystals were combined with MnCo2O4 nanoparticles (NPs) to construct MnCo2O4/YVO4 heterostructure candidates using an easy sol-gel approach. The constructed mesoporous YVO4 with a tetragonal structure has a large surface area of approximately 200.0 m2 g−1. Within 90-min visible light exposure, the 9.0 wt% MnCo2O4/YVO4 nanocomposite photocatalyst exhibited 100.0 % desulfurization efficacy, which was ∼25.0 folds greater than occurred using the unmodified YVO4 (only 4.0 %). Notably, the 9.0 wt% MnCo2O4/YVO4 photocatalyst displayed a desulfurization rate of ca. 269.19 μmol L−1 min−1, which was ∼55.00 folds higher than that occurred on the unmodified YVO4 material (4.90 μmol L−1 min−1). The constructed MnCo2O4/YVO4 heterostructure exhibited preeminently superb photocatalytic thiophene oxidation with superior recyclability than nonmodified YVO4. The n-n heterojunction construction between MnCo2O4 and YVO4 played a major role in synergistic promoting the photocatalytic efficacy of the MnCo2O4/YVO4 nanocomposite through enlarging the photoabsorbance capability and promoting photoexcited carriers’ separation. Moreover, the abundant surface reactive sites originating from the mesoporous nature of the constructed heterostructure candidates significantly contributed to enhancing the photocatalytic thiophene oxidation. The 9.0 wt% MnCo2O4/YVO4 candidate exhibited high stability within 600.0 min. Overall, this contribution not only presents a new MnCo2O4/YVO4 heterojunction, fabricated by an easy approach for highly efficient desulfurizing of thiophene but also provides good ideas for establishing other heterostructure materials.

Cobalt-based metal–organic framework for desulfurization of thiophene as a model fuel

Increased energy consumption from continued economic expansion generates environmental challenges and health hazards from burning fuel containing sulfur compounds. We explore the effectiveness of a cobalt-based MOF, BITSH-1, as an adsorbent to remove thiophene from model fuel.

The powerful combination of 2D/2D Ni-MOF/carbon nitride for deep desulfurization of thiophene in fuel: Conversion route, DFT calculation, mechanism

2D/2D Ni-MOF/g-C3N4 nanocomposite was utilized for desulfurization. The multilayer pore structure and high specific surface area of Ni-MOF/g-C3N4 promote the adsorption and conversion of thiophene. In addition, the two-dimensional structure exposes more active centers and shortens photogenerated carrier migration to the material surface distance, it enhances photogenerated charge transfer. The Ni-MOF and g-C3N4 construct a Z-scheme heterojunction structure with tight contact, it effectively enhances the material's photocatalytic redox ability. In the light, the material generates more photocarriers for the production of free radicals including hydroxyl radicals, holes, and superoxide radicals. The higher carrier concentration of Ni-MOF/g-C3N4 promotes the activation and oxidation of thiophene, consequently enhancing the photocatalytic desulfurization capability. The results showed that the conversion of thiophene was 98.82 % in 3 h under visible light irradiation. Radical capture experiments and analysis using electron paramagnetic resonance spectroscopy demonstrated that superoxide radicals, holes, and hydroxyl radicals played crucial roles in PODS (photocatalytic oxidative desulfurization). In addition, DFT (density functional theory) calculations were conducted to determine the paths of electron migration and TH (thiophene) adsorption energy. Finally, a mechanism for photocatalytic desulfurization was proposed based on the comprehensive analysis of theoretical calculations and experimental studies.

Adsorptive desulfurization of thiophenic sulfur compounds using nitrogen modified graphene

In this study, nitrogen modified graphene was investigated for adsorptive desulfurization of thiophene, benzothiophene and dibenzothiophene. For these compounds, graphene (257 m2/g and 0.48 cm3/g) showed adsorptive removal of 70.1, 65.4 and 61.2%, respectively. Nitrogen modification enhanced separation of graphene layers, resulting in increase of surface area and pore volume. With increase in nitrogen content, both properties were further enhanced. The highest surface area (301 m2/g) and pore volume (1.12 cm3/g) were obtained for 14-N-GR with highest nitrogen content of 13.8 wt%. Adsorptive removal was thereby, highest for 14-N-GR, with 97.3, 92.8 and 88.4%, respectively for thiophene, benzothiophene and dibenzothiophene. The pyrrolic-N and pyridinic-N within carbon matrix contributed significantly to π-π interactions between carbon matrix and sulfur compounds. The order of adsorptive removal efficiency for sulfur compounds was also associated with their molecular size. The adsorptive desulfurization was best described by pseudo-second-order kinetics and best represented by Langmuir adsorption model. The monolayer model agreed with major contribution of π-π interactions between adsorbate and adsorbent surface. The spent adsorbents regenerated using thermal process showed cyclic and thermal stability. After five adsorption-regeneration cycles, percentage removal decreased only up to 14%, without any major morphological change of adsorbent.

Adsorptive desulfurization of thiophene using Cu-CNF slurry in a coiled flow inverter with recycling

This study presents an alternative to adsorptive desulphurization (ADS) process in packed beds by making use of enhanced radial mixing prevalent in coiled flow inverter (CFI). We describe the synthesis of Cu-tartrate as the precursor for Cu-carbon nanofiber (Cu-CNF) and the application thereof in ADS of liquid fuels in a CFI. Thiophene was removed from n-hexane using a slurry of Cu-CNF in the liquid. The data show the sulfur (S) - loading of 103 mg/g in Cu-CNF at 2000 ppmw-S concentration of thiophene in the liquid at 120 cc/min flowrate using five CFI units connected in series. Recycling was introduced for the first time in CFI, and three CFI units connected in series with the recycle ratio of 2 were sufficient to achieve the same removal efficiency as with five CFI without recycling. The results indicate that CFI is an efficient technology and has potential to replace packed bed adsorbers.

Perovskite CuO@BaSnO3 nanorods photocatalysts with promoted visible light ability for desulfurization of thiophene

BackgroundThe desulfurization of fuels is critical to upgrade their performance and to match the demands of sulfur standards MethodMesoporous p-n heterojunctions CuO/BaSnO3 nanorods were fabricated by the hydrothermal process in the presence of polyvinylpyrrolidone. The photocatalytic performance of the synthesized CuO/BaSnO3 nanorods at various CuO percentages compared with the pristine BaSnO3 was evaluated by desulfurising thiophene under visible light illumination Significant findingsXRD and HRTEM results verified the fabrication of perovskite BaSnO3 in cubic structure and CuO in the monoclinic phase, and TEM images of CuO/BaSnO3 exhibited nanorod-like morphology with a length of 100 nm and width of 10 nm decorated with CuO NPs (5 nm). After optimization, the experimental results showed that with a photocatalyst dosage of 2 g/L and CuO percentage of 15%, the maximal desulfurization rate of thiophene was around 100% within 60 min. The rate constant of 15% CuO/BaSnO3 photocatalyst was the maximum, and it was enhanced larger 3.36 times than that of the pristine BaSnO3 nanorods. The photocurrent intensity of 15% CuO/BaSnO3 photocatalyst was enhanced 9.2 times greater than that of pristine BaSnO3. The enhancement of the desulfurization rate illustrated that the creation of an internal electric field through the p-n heterojunction CuO/BaSnO3 system could facilitate the separation of photoinduced holes and electrons, improving the charge transport ability and hence promoting the photocatalytic performance. PL, transient photocurrent responses and electrochemical impedance results were determined to confirm our photocatalytic results. Cycling runs displayed that the obtained CuO/BaSnO3 photocatalyst still exhibited high photocatalytic ability and stability after five cycles. This work is anticipated to strengthen the design of effective and novel p-n heterojunctions photocatalysts for practical photocatalysis applications in terms of H2 production and detoxification of toxic organic compounds.

Mesoporous zirconia- supported PdO nanoparticles with promoted their photocatalytic ability for desulfurization of thiophene

Mesoporous zirconia- supported PdO nanoparticles with promoted their photocatalytic ability for desulfurization of thiophene

Extractive desulfurization of thiophene by tetraethylene glycol at T = 298.15 to 313.15 K and liquid–liquid phase equilibrium study

ABSTRACT This study provides the complete liquid–liquid equilibrium (LLE) data including the solubility curves and tie-lines for heptane + thiophene + tetraethylene glycol and cyclohexane + thiophene + tetraethylene glycol ternary mixtures at 298.15–313.15 K under a pressure of 83.4 ± 1 kPa. The experimental data were obtained by the cloud point method. Type 1 phase behavior is observed for the systems. The observed behavior was interpreted based on the type and nature of the interactions between the components. The capability of tetraethylene glycol in extractive desulfurization of thiophene from liquid fuel is evaluated by determining the solute distribution coefficient and selectivity. The high values of the selectivity show that tetraethylene glycol is a good candidate for this purpose. The investigation of the effect of temperature on the area of the biphasic region and distribution ratios shows that the extraction process can be performed at room temperature. The experimental data were successfully correlated with the NRTL model. The reliability of the correlation results was checked by using a Graphical User Interface (GUI) for the representation of Gibbs energy of mixing (GM). The root mean square deviation (RMSD), a measure of the precision of the correlations, ranges from 0.0022 to 0.0040.

Promoted visible-light-driven oxidative desulfurization of thiophene over mesoporous PdO-incorporated BaSnO3 nanocomposites

An emerging method for removing sulfur-containing materials like thiophene, known as photocatalytic oxidative desulfurization, utilizes moderate temperatures and pressures without the use of H2 gas, unlike hydrodesulfurization. Here, we used a hydrothermal technique to produce Barium stannate nanoparticles (BaSnO3 NPs). A PdO/BaSnO3 photocatalyst was then fabricated by adding small amounts (0.5–2.0% wt) of PdO to mesoporous BaSnO3. After 150 min under illumination, the developed PdO/BaSnO3 photocatalyst showed complete thiophene photooxidative desulfurization and had excellent recyclability. The designed nanocomposite containing 2.0 wt% of PdO, displayed improved absorption of visible light with a bandgap reduction from 2.98 to 2.21 eV. Photoluminescence and photocurrent data of the developed photocatalysts demonstrated that the recombination of the photogenerated charge carriers was also whittled down. According to kinetic studies, the PdO content and the photocatalyst dose had a significant impact on the reaction rate which follows the pseudo-first-order model. Additionally, the mechanism of photooxidation of thiophene was discussed. This research will pave the way for the wide use of perovskite oxide photocatalysts to oxidize sulfur-containing materials under visible illumination.

Hierarchical mesoporous CuO/ZrO2 nanocomposite photocatalyst for highly stable photoinduced desulfurization of thiophene

The production of ultra-low sulfur or sulfur-free fuel has become a remarkable challenge in fuel generation. Herein, an efficient and straightforward strategy to develop mesoporous CuO/ZrO2 nanocomposite photocatalyst was achieved for thiophene desulfurization under visible exposure. TEM image presented the co-existence of CuO and ZrO2 in the as-constructed heterojunctions with close contact and an average particle size of 45 nm. The obtained mesoporous CuO/ZrO2 photocatalyst exhibited a much larger photocatalytic ability toward the thiophene oxidation compared with pristine ZrO2. The photocatalytic efficiency for thiophene oxidation over 7%CuO/ZrO2 nanocomposite was 100% within 120 min. The optimized 7%CuO/ZrO2 nanocomposite showed 2.62 folds superior photocatalytic ability for thiophene oxidation compared to pristine ZrO2. The rate constant of 7%CuO/ZrO2 nanocomposite was determined 0.0172 min−1, which boosted 3.5 folds greater than ZrO2 NPs. The superior photocatalytic performance of the CuO/ZrO2 photocatalysts is explained by the constructed heterojunctions to build the S-scheme mechanism, large surface area, intense absorption in the wide visible region, ease separation of electron-hole, and design mesopore of the CuO/ZrO2 photocatalysts. The recyclability exhibited the stability of photocatalytic oxidation of thiophene for five consecutive recycle runs. The plausible photocatalytic oxidation of the thiophene mechanism over CuO/ZrO2 photocatalyst was addressed. Thus, the current research opens a green and efficient avenue for the desulfurization of thiophene under moderate conditions, and it provides a novel insight for utilizing ZrO2-based photocatalyst to treat pollutants under visible light.

Fabrication of BiVO4 nanosheets decorating by V2O5 nanoparticles for the enhanced photocatalytic desulfurization of thiophene

BiVO4 nanosheets were synthesized using the hydrothermal approach with the support of sodium dodecyl benzene sulfonate. V2O5 nanoparticles (NPs) at different percentages were uniformly distributed on BiVO4 nanosheets through the impregnation process to construct n-n heterojunction V2O5/BiVO4 nanocomposites. The synthesized V2O5/BiVO4 nanocomposite photocatalyst was assessed for photocatalytic oxidation of thiophene under visible illumination. TEM images and XRD exhibited that the synthesized nanocomposites are constituted from orthorhombic and V2O5 monoclinic BiVO4 and V2O5 NPs well-distributed onto the sheet-like structure with the particle diameters of 10–20 nm. The combination of V2O5 over BiVO4 nanosheets led to a remarkable boost in thiophene conversion ability from 45 % to 100 %. The 10 % V2O5/BiVO4 photocatalyst exhibited the highest photocatalytic desulfurization ability (100 %) within 90 min. The rate constant value over 10 %V2O5/BiVO4 photocatalyst was determined at about 0.0311 min−1, which was 2.9 folds larger than that of bare BiVO4 nanosheets (0.0107 min−1). The enhanced photocatalytic ability over V2O5/BiVO4 nanocomposites was implied in the design of heterojunction with the synergistic effect. The n-n heterojunction significantly enhanced the lifetime and separation efficiency of the photoinduced carriers in the V2O5/BiVO4 nanocomposites.

Ultrasound-Assisted Synthesis of a N-TiO2/Fe3O4@ZnO Complex and Its Catalytic Application for Desulfurization

Ultrasound (US)-assisted synthesis of a N-doped TiO2 catalyst supported on magnetically separable Fe3O4@ZnO particles and its subsequent application for catalytic desulfurization were performed in the present work. The catalyst was also synthesized conventionally to compare the role of acoustic cavitation (US horn working at 20 kHz frequency) in improving the catalyst characteristics. The effects of different ultrasonic (US) power (80 W to 120 W) and duration (15 min to 75 min) were studied to elucidate the best operating conditions for obtaining the minimum particle size of the catalyst. Under optimal conditions of 80 W power and 30 min of time, a minimum particle size of 31.22 μm was obtained. The particle size for the conventionally synthesized catalyst was 806.4 µm, confirming that the particles were agglomerated in the absence of ultrasound. The synthesized catalyst was used for the desulfurization of thiophene to assess the performance of the catalyst, along with a comparative study between the conventionally synthesized catalyst and that obtained using the US-assisted approach. It was evident that the performance of the catalyst synthesized sonochemically was superior, as US enhanced the activity of the catalyst by reducing the particle size and achieving homogeneity. The desulfurization achieved using the sonochemically synthesized catalyst was 47% in 100 min at a 2 g/L catalyst dose and a 3 mL/L H2O2 dose. The desulfurization was only 25% using the conventionally synthesized catalysts under the same operating conditions. Overall, the present work demonstrates the advantages of US in improving the catalyst characteristics, as well as the successful application of catalyst in desulfurization.

Oxidative Desulfurization Activity of NIT Nitroxide Radical Modified Metallophthalocyanine.

In the present study, metallophthalocyanines were modified with NIT nitroxide radicals through chemical bonds to prepare a series of metallophthalocyanines–NIT catalysts (MPcTcCl8-NIT, M=Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) applied for oxidative desulfurization of thiophene (T) in model fuel. The MPcTcCl8-NIT catalysts were characterized by FTIR, UV-Vis, ESR, and XPS spectra. The oxidative desulfurization activity of MPcTcCl8-NIT catalysts was studied in a biomimetic catalytic system using molecular O2 as the oxidant. The MPcTcCl8-NIT catalysts exhibited high catalytic activities for the oxidation of thiophene in model fuel. The desulfurization rate of ZnPcTcCl8-NIT for thiophene reached to 99.61%, which was 20.53% higher than that of pure ZnPcTcCl8 (79.08%) under room temperature and natural light. The results demonstrated that MPcTcCl8-NIT catalysts could achieve more effective desulfurization rate under milder conditions than that of the metallophthalocyanines. The NIT nitroxide radicals also could improve the catalytic activity of metallophthalocyanine based on the synergistic oxidation effect. The stability experiments for ZnPcTcCl8-NIT showed that the catalyst still had a high desulfurization rate of 92.37% after five times recycling. All these findings indicate that the application of MPcTcCl8-NIT catalysts provides a potential new way for the desulfurization performance of thiophene in fuel.

Mesoporous MoS2 incorporated zirconia nanocomposites: Simple synthesis, characterization and photocatalytic desulfurization of thiophene under visible light

The petroleum sector has focused its efforts on developing low-sulfur fuels because of rigorous regulatory requirements enforced by various countries. In this context, mesoporous MoS2/ZrO2 nanostructures were simply manufactured and subsequently adopted under visible light for photocatalytic desulfurization of thiophene (PDT). Actually, PDT was extensively upgraded upon the application of MoS2/ZrO2 nanostructures especially when the results compared to pure ZrO2. The pseudo-first-order model was the best model that was found to properly fit such a reaction. Amongst all manufactured specimens, the photocatalytic efficiency of the 1.5 wt% MoS2/ZrO2 nanostructured material was the maximum. The reaction rate of PDT upon utilizing optimized material was 0.01577 min−1 whiles that upon the application of pure ZrO2 was 0.000513 min−1. And so, PDT rate was 30.5 times greater over 1.5 wt% MoS2/ZrO2 nanostructured material than over pure ZrO2. The photocatalytic oxidation of thiophene over the manufactured materials yielded SO3 and CO2. The distinct photocatalytic effectiveness of MoS2/ZrO2 might be associated with the competent absorption of visible light, fast movement of thiophene molecules to active centres, expanded hydroxyl radical content and diminished light scattering. The recyclability test acknowledged that MoS2/ZrO2 nanostructured material was remarkably stable against PDT under visible light. The mechanism of the PDT reaction utilizing the photo-created charges was discussed.

Photocatalytic Oxidative Desulfurization of Thiophene by Exploiting a Mesoporous V2O5-ZnO Nanocomposite as an Effective Photocatalyst

Due to increasingly stringent environmental regulations imposed by governments throughout the world, the manufacture of low-sulfur fuels has received considerable assiduity in the petroleum industry. In this investigation, mesoporous V2O5-decorated two-dimensional ZnO nanocrystals were manufactured using a simple surfactant-assisted sol–gel method for thiophene photocatalytic oxidative desulfurization (TPOD) at ambient temperature applying visible illumination. When correlated to pure ZnO NCs, V2O5-added ZnO nanocomposites dramatically improved the photocatalytic desulfurization of thiophene, and the reaction was shown to follow the pseudo-first-order model. The photocatalytic effectiveness of the 3.0 wt.% V2O5-ZnO photocatalyst was the greatest among all the other samples, with a rate constant of 0.0166 min−1, which was 30.7 significantly greater than that of pure ZnO NCs (0.00054 min−1). Compared with ZnO NCs, and owing to their synergetic effects, substantial creation of hydroxyl radical levels, lesser light scattering action, quick transport of thiophene species to the active recenters, and efficient visible-light gathering, V2O5-ZnO nanocomposites were found to have enhanced photocatalytic efficiency. V2O5-ZnO nanocomposites demonstrated outstanding stability during TPOD. Using mesoporous V2O5-ZnO nanocomposites, the mechanism of the charge separation process was postulated.

Changes in the sulfur forms of subbituminous coals during oxidation with hydrogen peroxide and peracetic acid

We have investigated chemical desulfurization of subbituminous coals to prepare ultra-low sulfur coal for the converter process in the steel industry. Herein, we report the oxidative desulfurization of thiophene contained in two subbituminous coals using two peroxides, hydrogen peroxide and peracetic acid. Sulfur K-edge X-ray absorption near edge structure analysis was carried out to follow the change in sulfur form during oxidation. Sulfur form distribution was determined quantitatively by deconvolution of the pyrite, thiophene, sulfoxide, sulfone, and sulfate peaks in the Sulfur K-edge XANES spectra of the raw and oxidized samples using the least-squares method. In the presence of hydrogen peroxide, oxidation was promoted only at 60 °C. Furthermore, an oxidation treatment was carried out at 20 °C using peracetic acid generated by mixing hydrogen peroxide and acetic anhydride, which selectively reacted with the sulfur atoms. Treatment with peracetic acid promoted the oxidation of thiophene and improved the desulfurization extent with low carbon loss. Sulfone-type sulfur formed by the oxidation of thiophene could be completely volatilized by heat treatment at 400 °C under a N2 gas stream. By combining pre-oxidation with peracetic acid treatment and pyrolysis, 74 % of total sulfur and 72 % of thiophene could be removed while recovering approximately 90 % of total carbon as char.

Effects of different zinc oxide morphologies on photocatalytic desulfurization of thiophene

Zinc oxide (ZnO) nanoparticles are superior photocatalysts for pollutant degradation due to their stability, low hazard, and high photosensitivity. The morphology of this material is one of the key factors influencing the performance of pollutant degradation. In fact, studies on the effects of different ZnO morphologies on thiophene desulfurization via photocatalysis process are limited. Thus, this study focuses on the performance of different ZnO morphologies for thiophene desulfurization. Nine ZnO nanoparticles were synthesized and categorized into two groups, namely flower-like and non-flower-like ZnO. Flower-like ZnO included flakes, clusters, rods, and needles, while the non-flower-like ZnO comprised nanoballs, short-nanorods, nanocubes, and nanoporous. The physical properties of all ZnO morphologies were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier-transform infrared (FTIR), and compared with commercial ZnO. From the findings, flower-like ZnO flakes showed the highest performance in thiophene desulfurization (30%). High pH and turbidity reduction in the permeate confirmed that the thiophene compound in the solution was highly degraded after treatment. Moreover, all ZnO morphologies applied to pseudo-second-order models due to higher linear regression (R2) values. Greater thiophene desulfurization was indicated by the highest Ce value of ZnO flakes (909.09 mg/g). The optimum conditions for thiophene desulfurization were at pH 7 and 0.05 g/L ZnO flakes loading for 90 min contact time.

Highly dispersive Cu species constructed in mesoporous silica derived from ZSM-5 for batch and continuous adsorptive desulfurization of thiophene

ZSM-5 zeolite with long narrow pore structure could restrict the adsorption of sulfur compounds from commercial fuels due to their larger molecular dimensions. Herein, ZSM-5 as silica precursor and CTAB as template was successfully employed using dissolution and self-assembly method to synthesize micro-mesoporous silica (MMZ). Compared with ZSM-5, MMZ materials could effectively overcome the diffusion pathway, enhance mesopores and enlarged the BET surface area (830 m2/g). After MMZ crystals were fabricated with 5-20 wt% Cu content by ultrasound facilitated impregnation strategy, the active sites were improved, which promoted thiophene adsorption capacity from 0.9 to 0.44 and 0.48 mmol/g via π-complexation conducted under dynamic (flow) conditions in a fixed bed adsorber and batch stirring tang reactor, respectively. And the desulfurization performances decline in the order 10Cu/MMZ >20Cu/MMZ > 5Cu/MMZ >10Cu/ZSM-5 > MMZ > ZSM-5. The higher adsorption capacity was tentatively linked with well dispersive Cu nanoparticles (NPs) and textural properties of MMZ. Furthermore, the ADS activity of Cu/MMZ towards thiophene can be recovered well without nominal loss.

Highly efficient Ag2O/Na-g-C3N4 heterojunction for photocatalytic desulfurization of thiophene in fuel under ambient air conditions

A composite photocatalyst of Ag2O and Na doped g-C3N4 (Ag2O/Na-CN) with high efficiency was investigated for photocatalytic oxidative desulfurization (PODS). The concentration and lifetime of carriers are increased with Na-CN. Under light conditions, it produces more charge carriers for the generation of radical species, such as superoxide radicals and holes. In addition, Na-CN and Ag2O form a p-n heterojunction, facilitating the transfer and separation of photogenerated electrons and holes, and increasing the concentration of holes on the valence band of Ag2O. The significantly improved charge separation alone with the higher carrier concentration of Ag2O/Na-CN makes the activation and oxidation of thiophene easier. Free radical capture experiments, electron paramagnetic resonance, and gas chromatography-mass spectrometry tests showed that holes, electrons, and superoxide radicals are the most critical active species in the PODS process, supporting the proposed PODS mechanism.