Desulfurization Mechanism Research Articles

Preparation of polymeric ionic liquid-coated magnetic nanoball catalyst and coupling peroxymonosulfate for catalytic oxidation desulfurization at room temperature

A heterogeneous catalyst was prepared by wrapping a poly 3-butyl vinylimidazole cobalt chloride ionic liquid (P[BVIM]CoCl3) around the surface of Fe3O4@SiO2 magnetic nanoballs. This catalyst was coupled with the oxidant peroxymonosulfate (PMS) for extraction catalytic oxidation desulfurization (ECODS). The prepared desulfurization catalyst had superparamagnetic properties, with a saturation magnetization of 32.5 emu/g. Moreover, this caalyst was multi-porous material, ans it had a specific surface area and pore volume of 8.14 m2/g and 0.018 cc/g, respectively. The average pore diameter of catalyst was 3.9 nm. The optimal experimental conditions were as follows: the initial sulfur content of the oil was 500 ppm, the catalyst dosage was 30 mg, PMS (20 wt%) dosage was 0.6 g, the ACN dosage was 2 g, and the oil sample size was 6 g. After 20 min, a sulfur removal rate of over 98 % was achieved at 20 °C. Furthermore, the unpurified catalyst still maintained high desulfurization activity after being used for 5 times, demonstrating good stability. The desulfurization mechanism was divided into two steps: first, DBT was oxidized to DBTO by SO4− free radicals, and second, the DBTO was further oxidized to DBTO2 by OH free radicals in a tandem reaction. The reaction rates for the two steps at 20 °C were 0.0144 sec−1 and 0.00115 sec−1, respectively. The activation energies associated with these steps were 65.65 kJ/mol and 105.22 kJ/mol, respectively. The quencher t-butanol had no effect on the first step but significantly inhibited the second step, meaning that DBTO became the main oxidation product. One potential application of this study is the utilization of t-butanol to regulate the oxygen content in organic sulfide oxidation products.

Towards highly exposed active sites via Edge-N-rich carbon nanosheet @ porous biochar for efficient H2S catalytic oxidation

In this study, Edge-N-rich carbon nanosheet @ porous biochar (NCN@PB) was synthesized successfully from waste biomass self-assembly in a simple and green approach. The accessible and efficient utilization of edge-N enriched on the surface, together with the hybrid structure of NCN@PB improved the H2S oxidation capacity up to 390.1 mg/g at room temperature, reflecting an 8-fold enhancement compared with the blank biochar. The Density functional theory calculation, in-situ DRIFTS, and the characterization results further uncovered the desulfurization mechanism of active sites. Edge-N species decreased the barriers in critical steps governing H2S catalytic oxidation, i.e., H2S dissociation and O2 activation, especially the pyrrolic N. This strategy is beneficial for the development of surface engineering on metal-free catalysts and provides a new idea for improving the catalytic combustion activity of N-doped biochar.

High-performance MgO-CaO/C for H2S oxidation prepared by a facile co-pyrolysis of magnesium gluconate and CaCO3

A low-cost and facile approach to fabricate high-capacity desulfurizers has drawn much interest in the field of H2S removal. In this study, porous carbon materials with dual active components of MgO and CaO were synthesized by a facile co-pyrolysis of magnesium gluconate and CaCO3, and their performance on room temperature H2S oxidation was investigated. The H2S capacity of optimal CaO-MgO/C is 666.5 mg/gcat., more than 50 times that of MgO/C derived from pure magnesium gluconate. The characterization results indicate that compared to MgO/C, the CaO-MgO/C prepared by this co-pyrolysis strategy has a more developed pore structure and abundant basic sites. Consequently, the H2S adsorption and activation over as-prepared materials are promoted by the co-pyrolysis with CaCO3, and the storage space of oxidation products is also increased, resulting in an extraordinary enhancement in the H2S capacity. In addition, the desulfurization and deactivation mechanisms over the as-prepared CaO-MgO/C are illustrated. This work provides a novel and facile route of developing efficient materials for room temperature desulfurization.

Study on desulfurization performance of Cu modified red mud-fly ash sorbent

In this paper, fly ash, red mud and Cu(NO3)2·3H2O were used to prepare Cu modified red mud-fly ash sorbent (CuRMFA) by hydration impregnation method, and the sorbent was used to remove SO2 from coal-fired flue gas. The effects of Cu loading and removal conditions (temperature, O2 concentration and NO concentration) on the desulfurization ability of sorbent were studied. The desulfurization performance and mechanism of CuRMFA were analyzed by experimental results and characterizations. The experimental results show that the sorbent CuRMFA can meet the ultra-low emission standard of SO2, and the optimal load of Cu is 20 mg/g. The optimal removal conditions were 500 ℃, 5% O2, 50 mg/m3 NO and 500 mg/m3 SO2, and when the desulfurization efficiency was greater than 93%, the breakthrough time and sulfur capacity were 65.5 min and 230.88 mg/g, respectively. The CuRMFA mainly removes SO2 by chemical reaction, and the desulfurized product exists in the form of SO42-. The conversion of Cu+ to Cu2+ can enhance the electron transfer, enhance the adsorption oxygen conversion and catalytic oxidation performance, which plays an important role in improving the desulfurization performance of the CuRMFA. That Cu modified RMFA is beneficial to form active component 2MgO·SiO2 and decompose of (CaO)12·(Al2O3)7, and can promote the uniform dispersion of active component, which is conducive to reducing the activation energy of desulfurization reaction and speeding up the reaction process.

Evaluation and mechanism of ultrasound-assisted electrochemical desulfurization using citric acid as the electrolyte solution

ABSTRACT Achieving the clean utilization of coal is the priority of the coal industries. This paper proposed an efficient electrochemical technology for coal desulfurization before combustion. It was explored that citric acid can chemically provide enough acidic conditions for desulfurization reactions, and the ultrasonic-enhanced treatment physically helps to remove sulfur from coal due to its cavitation effect and mechanical effect. So the experiments of ultrasound-assisted electrochemical desulfurization using citric acid as the electrolyte solution were conducted. They combined physical and chemical methods to effectively remove sulfur from coal. The optimal operating parameters of the desulfurization effect were achieved by qualitative and quantitative analysis of coal samples(coal slurry concentration of 66 g/L, electrolysis time of 8 h, electrolyte concentration of 1.5 mol/L, electrolysis voltage of 4 V, electrolysis temperature of 30°C, ultrasonic strengthening time of 1 h and ultrasonic intensity of 320 W.). The total sulfur removal efficiency reached 45.09%. The electrolytic desulfurization experiments removed samples’ sulfur contents, ash contents, and water. The crystal structures of gypsum, white iron ore, zinc sulfide, and the molybdenite mineral composition were also destroyed for purification. Gaussian simulations showed that C-S bonds and S-S bonds contained in non-thiophene organic sulfur are easier to remove, and S-S bonds are more likely to break than C-S bonds. This study realized the promotion of desulfurization with the ultrasonic wave and citric acid solution. It provides a new idea of synergistic desulfurization and is beneficial to reduce atmospheric sulfur pollution.

Study on the in situ desulfurization and viscosity reduction of heavy oil over MoO3–ZrO2/HZSM-5 catalyst

Heavy oil is characterized by high viscosity. High viscosity makes it challenging to recover and transport. HZSM-5, MoO3/HZSM-5, ZrO2/HZSM-5 and MoO3–ZrO2/HZSM-5 catalysts were developed to promote in situ desulfurization and viscosity reduction of heavy oil. The physical and chemical properties of catalysts were characterized by XPS, XRD, TEM, NH3-TPD, etc. The effects of temperature, catalyst type and addition amount on viscosity and composition of heavy oil were evaluated. The results showed that the presence of MoO3–ZrO2/HZSM-5 nanoparticles during aquathermolysis could improve the oil quality by reducing the heavy fractions. It reduced viscosity by 82.56% after the reaction at 280 °C and catalyst addition of 1 wt%. The contents of resins and asphaltic in the oil samples were 5.69% lower than that in the crude oil. Sulfur content decreased from 1.45% to 1.03%. The concentration of H2S produced by the reaction was 2225 ppm. The contents of sulfur-containing functional groups sulfoxide and sulfone sulfur in the oil samples decreased by 19.92% after the catalytic reaction. The content of stable thiophene sulfur increased by 5.71%. This study provided a basis for understanding the mechanism of heavy oil desulfurization and viscosity reduction.

Desulfurization mechanism of thiophene compounds in supercritical water

Thiophene and its derivatives, the major sulfur-containing compounds widely exist in crude oil, which will cause air pollution by releasing SOx during direct combustion. Hence, the desulfurization of thiophene compounds was essential. Supercritical water (SCW) treatment is a potential technique for sulfur removal and energy conversion. In this work, density functional theory (DFT) calculations and experiments are employed to study the decomposition of thiophene compounds in SCW. DFT shows that H2O plays the role of reactant as well as catalyst in the delocalization destruction of thiophene. Additionally, H2, the main gaseous product in SCW process, also promotes the decomposition of thiophene. What’s more, a larger substituent in thiophene lead to a higher reaction energy barrier for decomposition. Experimental results show that the maximum desulfurization rate of thiophene reaches 91.54% in SCW, which is almost 1.5 times as that in pyrolysis (61.06%) at 700 °C and 30 min. And dibenzothiophene with the largest substituent make the poorest performance in desulfurization compared with methyl-thiophene and benzothiophene, which proved the results of DFT calculations. Based on the above research, the detailed reaction pathways of dibenzothiophene are proposed, which may be critical in understanding the desulfurization of thiophene compounds and the resource utilization of crude oil in SCW.

C-S cleavage of dibenzothiophenes with or without steric hindrance by the interface between PtSx and ZnO

Desulfurization plays a critical role in refining crude oil to produce fuel and the manufacture of fine chemicals. However, its low efficiency becomes a great challenge for the present desulfurization if only the C-S cleavage is considered a promising approach to reducing hydrogen consumption under atmospheric pressure. Accordingly, we investigate the critical factors necessary to achieve high C-S cleavage of dibenzothiophenes under mild conditions of 0.1 MPa and H2/oil = 100. The mechanism of reactive adsorption desulfurization of dibenzothiophenes with or without steric hindrance at atmospheric pressure on Pt/ZnO is proposed by studying the adsorption model of active metal sites, the Pt efficiency in C-S cleavage influenced by the steric hindrance and the structural evolution of Pt active centers in the presence of sulfur adsorption/deposition. Based on both experimental and DFT results, we report C-S cleavage of dibenzothiophenes with (TOF = 15 h−1) or without steric hindrance (TOF = 128 h−1) that can be highly efficiently fractured (99.9%) by the interface between PtSx and ZnO. This work has great practical significance for developing atmospheric industrial adsorbents for ultra-deep reactive adsorption desulfurization.

Application of Ca-based adsorbents in fixed-bed dry flue gas desulfurization (FGD): a critical review.

Sulfur dioxide, which comes from the flue gas emitted by the steel and coal power industries, is extremely harmful to humans and the natural environment. Due to its high efficiency and economy, dry fixed-bed desulfurization technology and Ca-based adsorbents have attracted wide attention. In this paper, a detailed outline of the process of the fixed-bed reactor, performance indexes, economic value, recent research, and industrial applications of the dry fixed-bed desulfurization process was summarized. The classification and properties, preparation method, desulfurization mechanism, and influencing factors of Ca-based adsorbents were discussed. This review indicated the challenges in the commercialization of dry Ca-based fixed-bed desulfurization and demonstrated the possible solutions. It is beneficial to promote industrial application by improving the utilization efficiency of Ca-based adsorbent, reducing the amount of adsorbent and operation cost, and developing ideal regeneration methods.

Experimental and molecular dynamics study of fuel desulfurization process using deep eutectic solvent

The sulfur-containing compounds in China's crude oil mainly exist in the form of thiophene (TPs). More than 80% of TPs are composed of dibenzothiophene (DBT). The combustion of sulfur-containing fuel oil pollutes the air. Studies have shown that DES, as a new solvent similar to ionic liquids, has the advantages of simple preparation, easy availability of raw materials and high extraction rate. In this paper, experiments on DES synthesis were carried out to screen DES with the best extraction efficiency, and the effects of extraction operation temperature and initial sulfur concentration of raw oil on DES extraction and desulfurization were explored. The DES separation mechanism for DBT extraction from n-heptane-DBT was used as the simulated oil. Quantum chemistry was calculated for 9 commonly used DES, and the hydrogen bonding between DES-DET-n-heptane was analyzed by using the obtained σ-Profiles map information, and the selected DES was compared with the auxiliary experiment from the perspective of quantum chemistry. Then, the molecular dynamics (MD) simulation between different DES and raw oil was carried out, that is, the non-bond interaction energy, radial distribution function, spatial distribution function and mean square shift results of DBT-Heptane-DES calculated by molecular dynamics were used to deeply analyze the microscopic separation mechanism of DES extraction desulfurization. The results show that the DES composed of choline chloride/diethylene glycol can theoretically perform more efficient desulfurization operations, and this theoretical analysis method can provide a strong basis for the desulfurization of other types of DES and the separation of other systems.

ANALYSIS OF THE STRUCTURAL-CHEMICAL MILL DUPLEX-SYSTEMS OF SILICATE-SILICIDE OF LUNG-EARTH METALS. Message 3. The mechanism of desulfurization in the smelting of blast-furnace pig iron

The mechanism of cast iron desulfurization through structural and chemical reactions in smelting slags corresponding to the composition of the main mineral phases is presented: monticellite (MT, SiO2MgOCaO) → mervinite (MP, 2SiO2MgO3CaO) → ockermannite (OK, 2SiO2MgO2CaO) →diopside (DP, 2SiO2MgOCaO) → rankinite (pH, 2SiO23CaO) and eutectic slags (E, 3SiO2MgO4CaO). A sequential series of adsorption capacity of slag phases with respect to sulfur (АС, mas. %) and the depth of metal desulfurization – Δ(S), ppm was determined: Е (3.54/36) → MR (4.8/49) → OK (5, 7/59) → DP (7.14/74) → MT (9.8/103) → RN (20/222). In factory conditions, the efficiency of smelting slags of eutectic composition and diopside for ladle processing of cast iron was tested. The expediency of using such blast furnace slags for ladle processing of cast iron has been established, which at a consumption of 5-10 kg/t provide a desulfurization depth of 200-400 ppm. The consumption of slag is significantly reduced with the additional deoxidation of smelting slags with carbon during the release of melt in the ditch of the foundry and in the pig iron ladle.

CaCO3-ZnO loaded scrap rice-derived biochar for H2S removal at room-temperature: Characterization, performance and mechanism

Metal oxide loaded carbon-based materials have attracted extensive attention as promising desulfurizers to solve the problem of H2S emission at room temperature. However, low desulfurization capacity, difficult regeneration and high economic cost are the main problems of metal oxide loaded carbon-based desulfurizers, which limit their industrial application. Herein, a novel and low-cost CaCO3-ZnO loaded biochar (RCZ) was synthesized by one-step pyrolysis of scrap rice and metal salts for highly efficient H2S removal at room-temperature. The optimized RCZ-1-1-1-800 sample showed an excellent H2S removal ability of 834.48 mg/g at the reaction temperature of 25 °C, oxygen content of 10%, and relative humidity of 70% as compared to 29.31 mg/g achieved by the inactivated biochar (prepared without activator). Such an RCZ-1-1-1-800 desulfurizer also delivered a high H2S removal ability under different desulfurization conditions. The associated desulfurization mechanism of RCZ was the coupling of reactive adsorption and catalytic oxidation with sulfur being the main desulfurization product. Moreover, the as-fabricated RCZ also exhibited a high reusability, retaining about 95% of the initial H2S removal capacity after five adsorption/regeneration cycles. This work provides a promising idea for the preparation of low-cost and high-capacity metal oxide- and carbonate-loaded carbon-based desulfurizers.

New insights into the mechanism of reactive adsorption desulfurization on Ni/ZnO catalysts: Theoretical evidence showing the existence of interfacial sulfur transfer pathway and the essential role of hydrogen

As well known in the petroleum industry and academia, Ni/ZnO catalysts have excellent desulfurization performance. However, the sulfur transfer mechanism of reactive adsorption desulfurization (RADS) that occurs on Ni/ZnO catalysts remains controversial. Herein, a periodic Ni nanorod supported on ZnO slab was built to represent the Ni/ZnO system, and density functional theory calculations were performed to study the sulfur transfer process and the role of H2 within the process. The results elucidate that the direct solid-state diffusion of S from Ni to interfacial oxygen vacancies (Ov) is more favorable than the hydrogenation of S to SH/H2S on Ni and the subsequent H2S desorption, and accordingly, H2O is produced on Ni rather than on ZnO. Ab initio thermodynamics analysis shows that the hydrogen atmosphere applied in preparing Ni/ZnO catalysts greatly promotes the Ov formation on ZnO surface, which accounts for the presence of interfacial Ov in freshly prepared catalysts. Under RADS condition, hydrogenation of interfacial O atoms to form O−H groups facilitates the reverse spillover of these lattice O atoms from ZnO to Ni, accompanied with the interfacial Ov generation. In contrast to the classic S transfer mechanism via H2S, the present work clearly demonstrates that the interfacial S transfer is a feasible reaction pathway in the RADS mechanism. More importantly, the existence of interfacial Ov is an essential prerequisite for this interfacial S diffusion, and H2 plays a key role in facilitating the Ov formation.

Efficient purification of biogas using ionic liquid as absorbent: Molecular thermodynamics, dynamics and experiment

Biogas, as a cheap and easily available clean biomass energy, has attracted extensive attention. In this work, the simultaneous decarburization, desulfurization and dehydration of biogas with ionic liquids (ILs) was proposed. Based on the COSMO-RS model, the separation performance of 400 ILs composed of 20 cations and 20 anions was screened by using Henry's law constant (HLC) and selectivity coefficient as separation performance indexes. Among them, 1,3-dimethylimidazolium methylsulfate [C1MIM][MeSO4] was considered to be the most promising candidate absorbent. Furthermore, the HLC and selectivity of CH4, CO2 and H2S in [C1MIM][MeSO4] were predicted by COSMO-RS at different temperatures and pressures. The results show that the selected [C1MIM][MeSO4] has excellent selective absorption performance for CO2 and H2S. The regeneration experiment of [C1MIM][MeSO4] showed that the absorption effect of CH4, CO2 and H2S was almost unchanged (i.e., HLC was almost unchanged) after 6 absorption-desorption cycles. Molecular surface electrostatic potential (ESP) analysis was performed to obtain the binding sites of intermolecular interactions to reveal the separation mechanism of simultaneous decarbonization, desulfurization and dehydration of ILs. Interaction region indicator (IRI) analysis showed that IL [C1MIM][MeSO4] mainly interacted with the components to be separated in the form of hydrogen bonds. The spatial distribution function (SDF) reveals the spatial distribution of different gases around [C1MIM][MeSO4] from the perspective of cluster macromolecules. This provides theoretical insights into molecular thermodynamics and dynamics for the development of new ILs for biogas purification.

Biomethane purification with quaternary ammonium salts-based deep eutectic solvents: Experiment and computational thermodynamics

Biogas, as a clean renewable energy, has been paid more and more attention. In this work, the simultaneous decarburization, desulfurization and dehydration of biogas with quaternary ammonium salt-based deep eutectic solvent (DES) was proposed for the first time. Based on COSMO-RS model, the separation performance of 100 DESs composed of 10 hydrogen bond acceptors and 10 hydrogen bond donors was screened by using Henry's law constant and selectivity coefficient as separation performance indexes. DESs composed of TEAC, TEAB, TEG and BDO were considered as the most promising candidate absorbents. Furthermore, the solubility of CH4 and CO2 in four DESs was measured at different temperatures and pressures. The results show that the selected DESs have excellent selective absorption performance for CO2. The regeneration experiment of the DESs showed that its CO2 absorption effect was almost unchanged after 5 absorption–desorption cycles. Molecular surface electrostatic potential (ESP) analysis was performed to obtain the binding sites of intermolecular interactions to reveal the separation mechanism of simultaneous decarbonization, desulfurization and dehydration of DESs. The interaction energy analyzed the hydrogen bond formation potential between different molecules. Independent gradient model based on Hirshfeld partition (IGMH) analysis showed that DESs mainly interacted with the components to be separated in the form of hydrogen bonds. The spatial distribution function (SDF) reveals the spatial distribution of different gases around DES from the perspective of cluster macromolecules. This provides theoretical insights of molecular thermodynamics and dynamics for the development of new DES for biomethane purification process.

Preparation of Two-Dimensional Layered CeO2/Bi2O3 Composites for Efficient Photocatalytic Desulfurization

A two-dimensional layered CeO2/Bi2O3 composite was synthesized by microwave solvothermal method. X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), UV-Vis diffuse reflection spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS) were used to studied crystal structure, morphology, optical performance, elemental composition and the surface electronic state of the samples. The photocatalytic properties of the prepared samples were evaluated by photocatalytic desulfurization under visible light. When the molar ratio of Ce and Bi was 1:2, CeO2/Bi2O3 composite presented the highest photocatalytic desulfurization rate. Transient Photocurrent measurement, electrochemical impedance spectroscopy (EIS) and photoluminescence spectroscopy (PL) showed that CeO2 and Bi2O3 formed a heterojunction, which could promote the separation of photogenerated electrons and holes, improving the photocatalytic activity. Furthermore, it was found that the active species of hydroxyl radical (·OH) played an important role in the photocatalytic degradation of dibenzothiophene (DBT) based on the active species capture experiment. Finally, a plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite was proposed.

Deep Eutectic Solvents with Excellent Catalytic Ability for Extractive and Oxidative Desulfurization under Room Temperature

Deep eutectic solvents (DESs) have been intensively investigated as promising green solvents for extraction combined with oxidative desulfurization (EODS) of fuel oil. However, it is still a challenge to explore the effect of hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) structure on the formation of DESs and the performance of desulfurization. In this study, exploratory density functional theory (DFT) calculation was first carried out to reveal the influence of the electron density of HBA on the preparation of DES. Then, the structures of DESs were optimized, and their interaction energy was calculated. The structure of HBA and HBD has an important effect on the formation of DES and the capacity of EODS. Under optimal conditions (30 °C, O/S = 2), the desulfurization efficiency of phenol/formic acid (Ph/FA) DES can reach as high as 99.8%. Further, the desulfurization mechanism was also investigated by experiments, characterizations, and verified DFT calculations. This study not only provides a new aspect for designing and understanding DESs but also provides a novel catalyst for efficient EODS.

Pizo- catalytic desulfurization of model and real fuel samples over NiO/MnxOy nano-composite at room temperature: Mechanism and kinetic behind it

To desulfurize fuel with today's methods, extreme temperatures or oxidants such as H2O2 are required. NiO/MnxOy Nanocomposites were used as piezocatalysts in this study to remove sulfur compounds without adding any oxidants. As a result of our research, we have demonstrated that a piezo catalyst is more efficient and faster than a conventional catalyst. In addition, it provides high stability and high sulfur removal activity. It was demonstrated here that NiO/MnxOy Nanocomposites could remove 97 % of sulfur compounds in model fuel. They could also remove 61.1 % of sulfur compounds from fuel containing high sulfur content within 30 min. NiO/MnxOy Nanocomposites showed promising reusability. When the model fuel was subjected to 13 cycles for TP and DBTP removal, and 19 cycles for sulfur removal, it appeared that the removal efficiency had decreased slightly. Furthermore, a potential desulfurization mechanism has been proposed.

Group IIIA Single-Metal Atoms Anchored on Hexagonal Boron Nitride for Selective Adsorption Desulfurization via S-M Bonds.

Single-atom adsorbents (SAAs) featuring maximized atom utilization and uniform isolated adsorption sites have aroused extensive research interest in recent years as a novel class of adsorption materials research. Nevertheless, it is still challenging to gain a fundamental understanding of the complicated behaviors of SAAs for adsorbing thiophenic compounds (THs). Herein, this work systematically investigated the mechanisms of adsorption desulfurization (ADS) over a single group IIIA metal atom (Ga, In, and Tl) anchored on hexagonal boron nitride nanosheets (BNNSs) via density functional theory (DFT) calculations. First, all the possible doping sites have been considered and their stabilities have been evaluated by the doped energy. DFT calculations reveal that metal atoms prefer to substitute B atoms on BNNSs rather than N atoms. Additionally, SAAs all exhibit considerably enhanced adsorption capacity for THs primarily by the sulfur-metal (S-M) bond with π-π interactions maintained. Among them, In-atom-based SAAs would be adequate to provide the highest adsorption energy (In_cen_B, -40.1 kcal mol-1). Furthermore, from the perspective of adsorption energy, the SAAs show superior selectivity to THs than aromatic compounds due to the newly formed S-M bond. We hope that our work will manifest the design and application of SAAs in the field of ADS and shed light on a new strategy for fabricating SAAs based on BNNSs.

Efficient Diesel Desulfurization by Novel Amphiphilic Polyoxometalate-Based Hybrid Catalyst at Room Temperature.

Amphiphilic hybrid catalysts were prepared by modifying [SMo12O40]2- with tetrabutylammonium bromide (TBAB), 1-butyl-3-methylimidazole bromide (BMIMBr) and octadecyl trimethyl ammonium bromide (ODAB), respectively. The prepared catalysts were characterized by IR, XRD, SEM, TG and XPS. The desulfurization performance of the catalysts was investigated in model oil and actual diesel using hydrogen peroxide (H2O2) as an oxidant and acetonitrile as an extractant. All catalysts exhibited favorable activity for removing sulfur compounds at room temperature. Dibenzothiophene (DBT) can be nearly completely removed using SMo12O402--organic catalysts within a short reaction time. For different sulfur compounds, the [TBA]2SMo12O40 catalyst showed a better removal effect than the [BMIM]2SMo12O40 and [ODA]2SMo12O40 catalyst. The [TBA]2SMo12O40 dissolved in extraction solvent could be reused up to five times in an oxidative desulfurization (ODS) cycle with no significant loss of activity. The [BMIM]2SMo12O40 performed as a heterogeneous catalyst able to be recycled from the ODS system and maintained excellent catalytic activity. The catalysts showed a positive desulfurization effect in real diesel treatment. Finally, we described the ODS desulfurization mechanism of DBT using SMo12O402--organic hybrid catalysts. The amphiphilic hybrid catalyst cation captures DBT, while SMo12O402- reacts with the oxidant H2O2 to produce peroxy-active species. DBT can be oxidized to its sulfone by the action of peroxy-active species to achieve ODS desulfurization.