Thiophene Sulfide Research Articles

Atomically Permeated MoP‐WOx Core‐Shell Catalysts for Efficient and Selective Oxidation of Thiophenic Sulfides in Fuels via Direct Electron Transfer Mechanism

AbstractHeterogeneous interfaces designed rationally in catalysts can induce geometrical, compositional, and electronic effects that can be applied to modulate catalytically active sites and consequently accelerate reaction kinetics. Here, a core‐shell heterostructure catalyst consisting of crystalline molybdenum phosphide (MoP) cores and amorphous tungsten oxide (WOx) shells on porous carbon nanosheets (PCN) is developed for oxidative desulfurization (ODS) of fuels. The strongly coupled core‐shell heterogeneous interface triggers a distinctive atomic permeation effect that induces substantial electron transfer from MoP to WOx and subsequent generation of electron‐rich W sites, consequently optimizing the adsorption of intermediates and substrates. The resulting catalyst (WOx@MoP/PCN) demonstrates a turnover frequency as high as 768.1 h−1 for ODS at 60 °C, exceeding that of almost all the state‐of‐the‐art ODS catalysts by 1–2 orders of magnitude. Moreover, a novel surface oxidation pathway based on direct electron transfer is identified in the WOx@MoP/PCN‐H2O2 system, which bypasses the formation of reactive oxygen species, consequently endowing the system with a moderate redox potential. Thus, WOx@MoP/PCN exhibits unprecedented selectivity, achieving 100% removal of thiophenic sulfides from real diesel with minimal consumption of oxidant.

Constructing light-insensitive Ag(I) sites by in situ integration of nanoheaters for efficient adsorptive desulfurization

The π-complexation between Ag(I) and thiophene sulfides is considered as one of the key factors to selectively remove thiophenic compounds, but its application is very limited due to the instability of Ag(I) under light as well as the energy-intensive regeneration. In this study, stable and photothermal Ag(I)/Ag(0) composite sites are constructed in metal-organic frameworks (MOFs) and act as target-specific adsorption sites for the uptake of thiophenic compounds. Partial Ag(0) nanoparticles that were in situ introduced in MOF pores are oxidized to Ag(I). As a result, Ag(I) becomes light-insensitive because the light-induced electron of Ag(I) can be transferred to the integrated Ag(0) nanoparticles, protecting Ag(I) from reduction. Furthermore, Ag(0) nanoparticles are photothermal due to the localized surface plasmon resonance, thus can precisely heat Ag(I) for desorption by converting visible light to energy. This work provides a new avenue to stabilize Ag(I) and efficiently regenerate adsorbents.

Intramolecular Donor–Acceptor Design in Porous Organic Framework for Liquid Fuels Adsorption Desulfurization

AbstractA porous organic framework containing well‐defined donor–acceptor units, named donor–acceptor porous organic framework (D–A‐POF), is successfully synthesized. The localized electric field gradient at the pore surface induced by the intramolecular donor–acceptor (D–A) interactions endows D–A‐POF with excellent desulfurization capabilities. D–A‐POF exhibits high adsorption capacity of 3‐methylthiophene (12.26 mmol g−1, 392.32 mg S g−1) and 1‐benzothiophene (793.65 mg g−1, 189.25 mg S g−1) with impressive adsorption selectivity. Density functional theory calculations provide compelling evidence of the preferential selective adsorption of aromatic thiophene sulfides in D–A‐POF. In fixed‐bed breakthrough experiments, D–A‐POF demonstrates its ability to selectively capture thiophene sulfides from model gasoline, resulting in fuel with sulfide content below 10 ppb. The high stability and high desulfurization efficiency of D–A‐POF make it promising as a new porous adsorbent for ultra‐depth adsorption desulfurization.

Atomically Dispersed Aluminum Sites in Hexagonal Boron Nitride Nanofibers for Boosting Adsorptive Desulfurization Performance.

The exploitation of highly efficient and cost-effective selective adsorbents for adsorptive desulfurization (ADS) remains a challenge. Fortunately, single-atom adsorbents (SAAs) characterized by maximized atom utilization and atomically dispersed adsorption sites have great potential to solve this problem as an emerging class of adsorption materials. Herein, aiming at improving the efficiency of ADS performance via the economical and feasible strategy, the desirable SAAs have been fabricated by uniformly anchoring aluminum (Al) atoms on hexagonal boron nitride nanofibers (BNNF) via an in situ pyrolysis method. Remarkably, Al-BN-1.0 exhibited a superior adsorption capacity of 46.1 mg S/g adsorbent for dibenzothiophene, with a 45% increase in adsorption capacity compared to the pristine BNNF. Additionally, it demonstrated excellent adsorption of other thiophene sulfides. Moreover, the ADS mechanisms have been investigated through special adsorption experiments combined with density functional theory (DFT) calculations. It was demonstrated that the superior ADS performance and selectivity of Al-BN-1.0 originate from the sulfur-aluminum (S-Al) and π-π interactions cooperating synergistically. This work would cast light on a novel fabrication strategy for the SAAs based on the two-dimensional material with a tunable metal site configurations and densities for varied selective adsorption and separation.

Synthesis of Flower-Like Cobalt–Molybdenum Mixed-Oxide Microspheres for Deep Aerobic Oxidative Desulfurization of Fuel

Flower-like cobalt–molybdenum mixed-oxide microspheres (CoMo-FMs) with hierarchical architecture were successfully synthesized via a hydrothermal process and subsequent calcination step. The characterization results show that CoMo-FMs were assembled from ultrathin mesoporous nanosheets with thicknesses of around 4.0 nm, providing the composite with a large pore volume and a massive surface area. The synthesized CoMo-FMs were employed as catalysts for the aerobic oxidative desulfurization (AODS) of fuel, and the reaction results show that the optimal catalyst (CoMo-FM-2) demonstrated an outstanding catalytic performance. Over CoMo-FM-2, various thiophenic sulfides could be effective removed at 80–110 °C under an atmospheric pressure, and a complete conversion of sulfides could be achieved in at least six consecutive cycles without a detectable change in chemical compositions. Further, the catalytic mechanism was explored by conducting systemic radical trapping and transformation experiments, and the excellent catalytic performance for CoMo-FMs should be mainly due to the synergistic effect of Mo and Co elements.

A comprehensive method of ionic liquid screening and experimental verification for simultaneous separation of multiple sulfides from oil

Ionic liquid (IL) as the extractant has shown an excellent performance in oil desulfurization. However, it is still a great challenge to select an appropriate IL that can simultaneously remove multiple sulfides from oils due to enormous ILs' quantities. In this work, an ILs' screening method based on the fuzzy comprehensive evaluation function and COSMO-RS method was developed for oil extraction desulfurization. Four typical aromatic thiophene sulfides – thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) were considered as the removal targets, and n-heptane was chosen as the model oil. By this method, a single IL – 1-butyl-3-methylpyridinium dicyanamide ([BMPy][DCA]) was selected from 702 ILs for removing the four sulfides from n-heptane. Liquid-liquid equilibrium (LLE) data of n-heptane + TS/BT/DBT/4,6-DMDBT + [BMPy][DCA] systems at 298.15 K were measured and then correlated by the NRTL equation. A data processing method for LLE experimental indices, distribution coefficient and selectivity, was proposed for their crossed curves and different measuring ranges to facilitate the comparison of ILs' extraction performance. The comprehensive experimental indices based on this processing method were compared with the comprehensive predicted indices obtained by screening. The results showed a consistent trend between the two, and the excellent desulfurization performance of [BMPy][DCA] was confirmed. The separation mechanism was then analyzed through the quantum chemistry method. The results showed that the interactions of four sulfides with either n-heptane or [BMPy][DCA] both were the van der Waals interaction and steric effect. The [BMPy][DCA] could attract the sulfides more potently than the n-heptane, demonstrating the extraction's mechanism and characteristics. The stronger itself interactions of BT, DBT and 4,6-DMDBT as solid sulfides limited their solubility in liquid–liquid two phases. In addition, the decomposition of interaction energy showed that the attraction between the sulfides and the [BMPy][DCA] was dominated by dispersion, assisted by electrostatics, and equipped with a small amount of induction. The essence of repulsion between them was the exchange-repulsion.

1,8‐diazabicyclo [5.4.0] undecano‐7‐ene functionalized ionic liquids for extractive desulfurization of fuels

AbstractBACKGROUNDWith strict regulations on environmental protection, the removal of sulfur compounds from fuels has become increasingly urgent by extraction desulfurization technology.RESULTSA series of ionic liquid (IL) extractants for the removal of sulfides [benzothiophene (BT), thiophene (TH) and dibenzothiophene (DBT) in model oil] was developed. The ILs with functionalized 1,8‐diazabicyclo [5.4.0] undecano‐7‐ene (DBU) cations and large volume difluoromethane sulfonimide (NTf2) anion as raw materials were synthesized. The performance of the ILs was characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis and nuclear magnetic hydrogen spectroscopy (1H‐NMR) and other methods. Maximum removal efficiencies of 65.08% TH, 83.02% BT and 89.72% DBT were achieved in the presence of [CoDBU][NTf2] with functionalized carboxylation groups. In addition extractive desulfurization (EDS) was studied by tailoring the acid–base functional groups and viscosity of ILs. FTIR and the analysis of interaction energies were adopted to explore the interaction of ILs and sulfides. This indicated that the cooperative effects of hydrogen bonding, electrostatic interaction and π‐π interaction between sulfides and ILs were closely related to the high removal efficiencies of sulfides.CONCLUSIONSThe experimental results show that [CoDBU][NTf2] with functional carboxyl group is a clean and efficient extractant suitable for removing thiophene sulfides from model fuel oil. This work provides a reference process for the desulfurization of fuel oil in industry. © 2022 Society of Chemical Industry (SCI).

MoOx nanoclusters decorated on spinel-type transition metal oxide porous nanosheets for aerobic oxidative desulfurization of fuels

Aerobic oxidative desulfurization (AODS) represents an economical and sustainable way for desulfurization of petroleum fractions, which calls for high-performance catalysts to convert thiophene sulfides into sulfones under mild temperatures. In this work, we report that MoOx nanoclusters decorated on spinel-type porous metal oxide nanosheets can be utilized as an efficient and durable catalyst for the AODS reactions. We show that the electronic structure of the MoOx nanoclusters can be effectively modulated by the metal oxide carriers, and thereby identify the Mo(V) species to be the active center in this reaction. The optimal process with MoOx/CuCo2O4 as the catalyst, air under atmospheric pressure as an oxidant source could drive the aerobic transformation of dibenzothiophene at 90 °C with a turnover frequency of 16.2 h−1. Moreover, no catalytic performance attenuation and chemical structure deformation are observed in the six successive reuses. This work provides both fundamental and practical insights into the development of highly active and stable nanocluster catalysts.

Construction of rational defective CPO-27-Ni using N, N-dimethyloctadecylamine as template towards enhanced adsorptive desulfurization from fuel

Deep desulfurization from fuel has gradually become a research hotspot with enhancing requirements of environmental protection. CPO-27-Ni was considered as one of promising adsorbents towards adsorption desulfurization by virtue of its prodigious high pore volume and high specific surface area. However, the dominant microporous channels in traditional CPO-27-Ni hinder the diffusion of thiophene sulfide and its derivatives with relatively large molecular size, which limits its desulfurization efficiency. Herein, we proposed a strategy to reasonably construct defective CPO-27-Ni with micro-mesoporous structure using N, N-dimethyloctadecylamine (DMA18) as a template, aim at improving the diffusion efficiency by introducing meso-pores. Different amounts of DMA18 were introduced to synthesize defective CPO-27-Ni (DMA18-C-X) by solvothermal method, and DMA18-C-0.5 (the mole ratio of added DMA18 to Ni2+ was 0.5) exhibited a satisfactory desulfurization performance. The dynamic breakthrough adsorption capacities of dibenzothiophene, benzothiophene and thiophene over the DMA18-C-0.5 were remarkably promoted, which were as high 3.79, 6.45 and 9.29 times as the traditional CPO-27-Ni, respectively. The crystal structure of CPO-27-Ni was not altered after adding template agent DMA18, while a uniform distribution of mesopores appeared. The largest mesopore attained a size of 2.8 nm, which effectively promoted the full exposure of more unsaturated Ni2+ active sites and enhanced the interaction between Ni2+ active sites and sulfides, resulting in strengthened adsorption desulfurization performance. This method of introducing proper defects to construct mesopores in MOFs provides some useful references for preparing high-efficiency desulfurization adsorbents.

MoS2 nanocrystals embedded in hierarchical hollow carbon microspheres for efficient aerobic oxidative desulfurization

Aerobic oxidative desulfurization (AODS) is an emerging sustainable technology for deep desulfurization of petroleum fuels, which requires robust catalysts to boost the efficient aerobic oxidation of thiophenes. Here we report a self-assembly approach to anchor homogeneously dispersed MoS2 nanocrystals into hierarchical hollow carbon microspheres for the efficient AODS of thiophenic sulfides. We show that MoS2 nanocrystals are vertically embedded in carbon nanosheets with highly active edge sites exposed to the surface, which could activate the aerobic oxidation of dibenzothiophene at 100 °C, and achieves a turnover frequency of 7.53 h–1, higher than that of the reported metallic oxide catalysts. Through a combination of experimental research and theoretical calculations, we demonstrate that the Mo edge of MoS2 can effectively activate oxygen and strongly adsorb sulfides, which endows our catalyst with extraordinary performance. Moreover, the close coupling of MoS2 nanocrystals in carbon ensures their chemical stability, so that the catalyst maintains unattenuated activity and unchanged chemical structure over seven repeated uses. This work provides both fundamental and practical insights in the design of efficient and stable nanocrystal-based catalysts.

Low-temperature hydrothermal modification of waste paper fiber adsorbent to enhance removal benzothiophene sulfide efficiency from oil: kinetics and equilibrium study

Thiophene sulfide is difficult to be removed by hydrodesulfurization. In this study, ZnCl2-waste paper fiber activated carbon was used as adsorbent to remove thiophene sulfide from simulated oil by hydrothermal modification. Under the optimum condition of ammonia modification, the adsorption capacity of modified adsorbent to BT is 14.8 mg S/g, 2.98 times that of unmodified. BET, FTIR and Boehm analysis showed that the mesopore volume of ammonia modified adsorbent increased by 96.62% and the mesopore ratio increased from 12.58% to 43.40%, which was conducive to improving the adsorption rate. After modification, the basic groups on the surface of the adsorbent increased by 44.3 times, and –NH3+, –OH and –NH2 enhanced the electron attraction and hydrogen bonding force between the adsorbent and BT molecule. Adsorption isotherms, adsorption kinetics and adsorption thermodynamics show that the adsorption process is spontaneous, entropic and exothermic. The pseudo-second-order kinetic rate constant increases with the increase of adsorption temperature, indicating that the increase of temperature is beneficial to accelerate the adsorption rate. The adsorption desulfurization process follows the mechanism of single and multilayer adsorption mixing. The results of this study can help to reveal more clearly that biobased activated carbon can be modified to adsorb thiophene sulfide.

Efficient removal of thiophenic sulfides from fuel by micro-mesoporous 2-hydroxypropyl-β-cyclodextrin polymers through synergistic effect

Efficient removal of thiophenic sulfides is important for the purification of fuel. Herein, 2-hydroxypropyl-β-cyclodextrin polymers (2-HP-β-CDPs) with micro-mesopores are synthesized using 2-HP-β-CD and tetrafluoroterephthalonitrile (TFTPN) for removing thiophenic sulfides. The cross-linking of 2-HP-β-CD and TFTPN units forms the mesopores, and the cyclodextrin cavity acts as the micropores. The 2-HP-β-CDP1:4 (1:4 is the molar ratio of 2-HP-β-CD and TFTPN in preparation) possesses a surface area of 197.49 m2 g–1, and most of pores are at 1.09 nm of micropores and 6.06 nm of mesopores. The synergistic effect of the micro-mesopores promotes 2-HP-β-CDP1:4 to remove the thiophenic sulfides in the order of benzo[b]thiophene > 4,6-dimethyldibenzothiophene ≈ dibenzothiophene > thiophene. The removal efficiency and rate using 2-HP-β-CDP1:4 are better than those of CD-based and most traditional adsorbents that have been reported. Most of sulfides adsorbed by mesopores diffuse rapidly to micropores from the wide end of cyclodextrin and then are selectively captured by the cyclodextrin units in 2-HP-β-CDP1:4. These findings can guide the synthesis of CD-based polymers and the application of fuel purification.

Low-temperature aerobic oxidation of thiophenic sulfides over atomic Mo hosted by cobalt hydroxide sub-nanometer sheets

<h2>Summary</h2> Aerobic oxidation desulfurization (AODS) represents a carbon-neutral way to desulfurize petroleum distillates, yet it currently suffers from low efficiency and high temperature for the activation of triplet oxygen. Here, we report a sub-nanometer-thick cobalt hydroxide nanosheet that hosts an atomic molybdenum (Mo/Co(OH)₂) catalyst for the efficient aerobic oxidation of thiophenic sulfides. The catalyst achieves a turnover frequency of two orders of magnitude over that of state-of-the-art multi-metallic oxide catalysts and activates the reaction at 60°C. Coupling detailed characterizations with theoretical calculations, we formulate a descriptor—the work function of hosting materials for this reaction, which well explains the host identity dependence of the corresponding catalytic performance. We achieve the complete AODS of real diesel at 80°C under ambient pressure with negligible decay in consecutive reuses, highlighting the appealing industrial potential of our catalyst. Our findings provide fundamental and technological insights into implementing high-efficiency catalysts for the carbon-neutral AODS process.

CsPbBr3 and CsPbBr3/SiO2 Nanocrystals as a Fluorescence Sensing Platform for High-Throughput Identification of Multiple Thiophene Sulfides

Air pollution is a serious problem. Refractory thiophene sulfides, which cause air pollution, bring great challenges to their rapid and accurate identification. In this work, we propose a fluorescent sensor array based on two perovskite nanocrystals (CsPbBr3 NCs and CsPbBr3/SiO2 NCs) to distinguish different thiophene sulfides. The hydrogen bonding force between the thiophenics of thiophene sulfides and the amino groups of the perovskite NCs results in the weakening of the fluorescence signals of the perovskite NCs. The diverse interactions between thiophene sulfides and two perovskite NCs provide rich information, which can be obtained on the sensor array and identified by linear discriminant analysis. Five thiophene sulfides (i.e., benzothiophene, dibenzothiophene, 2-methylbenzothiophene, 3-methylthiophene, and thiophene) were discriminated by the sensor array at concentrations of 10-50 ppm. The effectiveness of the sensor array was further verified in the discrimination of blinded samples, in which all 10 samples were correctly identified. In addition, it is gratifying that even binary mixtures of thiophene sulfides could be distinguished by the proposed sensor array.

Interface engineering of quaternary ammonium phosphotungstate for efficient oxidative desulfurization of high-sulfur petroleum coke

Reducing the sulfur content in high-sulfur petroleum coke (HSPC) has become an urgent issue, however, remains a great challenge with the development of petroleum refining industry. Herein, a highly-efficient catalyst quaternary ammonium phosphotungstate ionic liquid [(C4H9)4N]3PW12O40 (C4@HPA) was initiated to activate H2O2, and the sulfur content of HSPC was remarkably decreased from 4.46 wt.% to 2.76 wt.% at a relatively mild temperature (70 oC), which is discernible below than 1400 oC in industry. The characterization results showed that only sulfate can be removed, while sulfoxide and sulfone were retained in petroleum coke. Moreover, the desulfurization activity of C4@HPA/H2O2 to thiophene sulfides decreases as follows: Thiophene > 2-Methylthiophene > 2,5-Dimethylthiophene > Dibenzothiophene > 4-Methyldibenzothiophene. It reveals that the sulfur of 4-MDBT is the most difficult to be removed. Therefore, this founding here may shine light on the understanding and construction of efficient catalyst for desulfurization of high-sulfur petroleum coke in industry.

Coordination unsaturation of vanadium nitride quantum dots boosts low-temperature aerobic oxidation of thiophenic sulfides.

Aerobic oxidative desulfurization (AODS) promises a sustainable alternative technology for diesel desulfurization, which necessitates the efficient aerobic oxidation of thiophenic sulfides under mild conditions to minimize energy input, yet being longstandingly plagued by the grand challenge in low-temperature activation of triplet oxygen. Here we synthesize vanadium nitride quantum dots on graphene to controllably create coordination-unsaturated edge/corner V sites for boosting the AODS reaction. The catalyst activates the reaction at 70 °C, and is two orders of magnitude more active than the best V-based catalysts. We demonstrate through computational studies that the low-coordinated edge/corner V sites can effectively activate oxygen and adsorb sulfides to lower the activation barrier, dramatically enhancing the activity. The catalyst achieves deep AODS of real diesel at 80 °C with negligible attenuation in successive reuses, which highlights its attractive industrial potential. These findings provide scientific and practical insights to develop high-performance catalysts for a sustainable AODS process.

Co-Fe-Mo mixed metal oxides derived from layered double hydroxides for deep aerobic oxidative desulfurization

Aerobic oxidative desulfurization (AODS) is a vital development aspect for the deep desulfurization of fuel, which requires catalysts with high performance to efficiently convert thiophenic sulfides to sulfones. Here CoFeMo mixed metal oxides (MMOs) were synthesized through the calcination of molybdate (MoO42-) intercalated CoFe layered double hydroxides (LDHs), which can serve as a robust and durable catalyst for AODS. The catalysts were synthetically characterized by using a range of techniques to identify its chemical and morphological properties, which showed that the content and electronic structure of Mo sites can be regulated by altering the intercalation content of MoO42-, and ultimately affect their catalytic performance. The optimal catalyst was capable of efficiently catalyzing the aerobic oxidative conversion of various thiophenic compounds into sulfones at 100 °C, and exhibited an excellent reusability by keeping the unchanged activity and chemical structure in repeated uses. This study would develop a feasible method to synthesize the highly efficient MMO catalysts for AODS of fuels.

Ultra-deep desulfurization of model diesel fuel over Pr/Ce–N–TiO2 assisted by visible light

The removal of thiophene sulfides was considered as one of the major steps for producing clean diesel fuel. We prepared a defect-rich Pr/Ce–N–TiO2 for breaking carbon-sulfur bonds of thiophene sulfides aided by visible light. Prepared photocatalysts of Pr/Ce–N–TiO2-2 had a large specific surface area of 114 m2/g and a pore diameter of 20–30 nm. The experimental results displayed the Turnover Frequency of thiophene, benzothiophene, dibenzothiophene, and 4, 6-dimethyl-dibenzothiophene was 50, 48, 45, and 49, respectively. Interestingly, the proper content of defects on the surface distinctly improved the activity of the oxidation and in situ hydrogenation of dibenzothiophenes. And desulfurization ratios were 100% when the composition of Pr3+, Ce3+, Ti3+, and Oads on the surface of the catalyst was 10.6, 6.6, 18.9, and 12.3%. The consequences of Photoluminescence emission spectra, Ultraviolet and visible spectrophotometry, and Electron paramagnetic resonance spectroscopy showed the co-doping of N, Pr, and Ce extended the photo-absorption range and increased the hole-electron separation of TiO2, which might be because the synergy of N, Pr, and Ce increased oxygen vacancies and defects on the catalytic surface, and formed lower gap energy leading to transfer and reserve electrons quickly under visible light. Also, we speculated the mechanism of photocatalytic desulfurization over Pr/Ce–N–TiO2 depending on the experimental results.

Research Progress of Phase Transfer Catalysts Used in Oxidative Desulfurization of Fuel Oil

The removal of sulfur compounds from fuel oil has been a major concern of the fuel industry. Hydrodesulfurization (HDS) is the most common desulfurization method currently used in oil refineries. However, HDS requires high temperature and high pressure conditions, consumption of hydrogen, and the removal effect of thiophene sulfides is not ideal. In view of defects of HDS, nonhydrodesulfurization technologies have been developed. Oxidative desulfurization (ODS) is regarded as the most potential desulfurization technology to replace HDS in industry because of mild operating conditions and high desulfurization efficiency. However, most ODS reactions are performed in heterogeneous systems. The common problem is that the oxidant and sulfur-containing compounds cannot contact effectively. Phase Transfer Catalysts (PTCs) are a class of catalysts that can assist in the transfer of reactants, thereby increasing mass transfer and accelerating the reaction rate of the heterogeneous ODS system. In this review, we divide PTCs applied to ODS into quaternary ammonium salts PTCs, ILs PTCs, polymers PTCs, supported PTCs and reaction-controlled PTCs, and will systematically introduce and summarize the research progress of PTCs used in ODS system. It is pointed out that reaction-controlled PTCs have a broad prospect in ODS system. In addition, the synthesis and recovery of PTCs will be briefly described.

Ultrasonic desulfurization of amphiphilic magnetic-Janus nanosheets in oil-water mixture system

Fe3O4 was obtained by reacting FeCl2 and FeCl3 with polyethylene glycol, and labeled onto a amphiphilic Janus nanosheet. It was confirmed by infrared spectroscopy, SEM, AFM and EDS that the Fe3O4 nanoparticles changed from hydrophilic to amphiphilic. The oxidative desulfurization performance of amphiphilic iron oxide was studied. Results showed that the Janus nanosheets labeled with Fe3O4 could significantly improve the removal rate of thiophene sulfide in simulated oil synergistically with ultrasonic waves, and the desulfurization rate could reach 100%. Further, the effect of ultrasound on the sensing ability of the oil–water interface was studied and the ultrasonic attenuation coefficient was calculated. In addition to the desulfurization mechanism of Fe3O4, it was found that although the ultrasonic attenuation coefficient of the amphiphilic nanosheets was high, the number of hydroxyl radicals determined the desulfurization efficiency. The amphiphilic Fe ions were more favorable for the formation of hydroxyl radicals than the single hydrophilic ones.