Microbial desulfurization of modeland straight‐run diesel oils

The desulfurization kinetics of Nocardia globerula R‐9 was investigated initially in a model system consisting of dibenzothiophene (DBT) dissolved in dodecane. The ability to desulfurize straight‐run diesel oil by resting cells of this strain was also evaluated. The course of desulfurization of DBT in dodecane could be represented by the Michaelis–Menten equation. The desulfurization of DBT and 4,6‐dimethyl dibenzothiophene (4,6‐DMDBT) in a mixture of the two proceeded simultaneously without preference for either of them. The sulfur content of the straight‐run diesel oil could be reduced from 1807 to 741 mg dm^?3 by treatment with resting cells of this strain, at a mean rate of 5.1 mmol sulfur kg^?1 h^?1. This showed that Nocardia globerula R‐9 could be a potential bacterium for reducing the sulfur content of petroleum products. Copyright © 2003 Society of Chemical Industry     

Deep desulfurization of hydrodesulfurized diesel oil by Pseudomonas delafieldii R‐8

Biodesulfurization is a promising technology for deep desulfurization. The remaining alkylated DBTs (dibenzothiophenes) in the HDS‐treated (hydrodesulfurized‐treated) diesel oil could be selectively and efficiently desulfurized by resting cells of Pseudomonas delafieldii R‐8, a Gram‐negative bacterium. The desulfurization activities of resting cells were greatly affected by W/O ratio (the volume ratio of aqueous phase to oil phase) and cell concentration. The desulfurization activity increased with the increase in the W/O ratio. When the W/O ratio and cell concentration were 2 and 25 mg cm^?3, the desulfurization activity was as high as 0.41 mg(total sulfur) g^?1(dry cell weight, DCW) h^?1, ie higher than that reported previously. GC‐AED (gas chromatography with an atomic emission detector) analysis showed that the total reductions for all the C1DBTs and C2DBTs were approximately 100%, 94.63% for C3DBT, and 97.09% for C4DBT (designated CxDBT, where x is the number of alkyl groups attached). The rates of biodesulfurization relate to the number and position of alkyl groups attached to the DBT. Copyright © 2005 Society of Chemical Industry     

A physiological study on growth and dibenzothiophene (DBT) desulfurization characteristics of Gordonia sp. CYKS1

Physiological characteristics of DBT desulfurization and cell growth ofGordonia sp. CYKS1 were investigated. It exhibited a preference to ethanol in a medium containing two carbon sources, ethanol and one of the carbohydrates used, glucose, sucrose, maltose, and galactose although it consumed both carbon sources simultaneously. Cell growth on ethanol or glucose followed the Monod kinetics. The optimal range of pH for the desulfurization of DBT and the cell growth was 7 to 8. The desulfurization rate decreased about 30% at pH 6, and no significant desulfurization or cell growth was observed at pH 5. As the initial DBT concentration increased up to 1.5 mM, the desulfurization rate also increased while no significant changes in the growth rate were observed. The maximum desulfurization rate was 12.50 μmol L^-1 h^-1 at an initial DBT concentration of 1.5 mM. Cell growth and desulfurization activity were severely inhibited by the presence of 2-hydroxybiphenyl (2-HBP). When 0.05 mM of 2-HBP was added at the beginning, both of the desulfurization rate and cell growth rate decreased about 20%. It was found that cell growth and desulfurization were completely inhibited in the presence of 2-HBP at 0.15 mM or a higher concentration. The inhibition by 2,2′-dihydroxybiphenyl (DHBP) was less severe than 2-HBP. About 80% of desulfurization activity was retained in the presence of 2,2′-DHBP at 0.4 mM.     

Deep oxidative desulfurization of model fuel using ozone generated by dielectric barrier discharge plasma combined with ionic liquid extraction

The dielectric barrier discharge (DBD) is often used to prepare ozone. In this study, a novel room temperature oxidative desulfurization method involving ozone oxidation produced in the DBD reactor combined with ionic liquid (IL) [BMIM]CH₃COO ([BMIM]Ac) extraction was developed. The method was suitable for the deep removal of sulfur (S)-containing compounds from model fuel. By this desulfurization technology, 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzothiophene (DBT), benzothiophene (BT) and thiophene (TS) were efficiently removed. Normally, the removal of TS and BT from fuel is highly difficult. However, using the proposed method of this study without any catalyst, the removal rate of TS and BT reached 99.9%. When TiO₂/MCM-41 was used as a catalyst, the S-removal of DBT and 4,6-DMDBT increased to 98.6 and 95.2%, respectively. The sulfur removal activity of the four sulfur compounds decreased in the order of TS > BT >> DBT > 4,6-DMDBT.     

基于阻滞扩散模型估算柴油脱硫吸附剂的适宜孔径分布

通过GC-PFPD色谱分析国Ⅱ、国Ⅲ、国Ⅳ标准0^#柴油中的主要含硫组分,发现苯并噻吩(BT)、二苯并噻吩(DBT)及其烷基取代衍生物是0^#柴油中的主要含硫化合物,C₂-DBT、C₃-DBT是国Ⅳ柴油中的主要含硫化合物。以BT、DBT、4,6-DMDBT为模型化合物,计算含硫化合物在不同大小孔道内的扩散阻滞因子,结合氧化铝堆积孔模型,估算氧化铝基柴油脱硫吸附剂的适宜孔径分布。结果表明,当氧化铝的平均孔径为4～10 nm时,含硫化合物的扩散阻滞因子为0.24～0.65,氧化铝的比表面积为100～250 m²·g^-1,可同时满足较低的扩散阻力和足够大的比表面积。对比分析不同氧化铝的孔分布及其吸附脱硫性能,结果表明氧化铝中4～10 nm范围内的孔面积占总孔面积的百分比与其吸附脱硫性能存在显著的正相关关系,初步推测氧化铝基脱硫吸附剂的适宜孔径分布范围为4～10 nm。     

V-Mo based catalysts for oxidative desulfurization of diesel fuel

Catalytic oxidative desulfurization (ODS) of a Mexican diesel fuel on a spent HDS catalyst, deactivated by metal deposits, was carried out during several reactive-batch cycles in order to study the catalytic performance to obtain low sulfur diesel. To explain catalytic activity results, Mo and/or V oxides supported on alumina pellets were prepared and evaluated in the ODS of a model diesel using tert-butyl hydroperoxide (TBHP) or H₂O₂ as oxidant. The catalytic results show that V-Mo based catalysts are more active during several ODS cycles using TBHP. The performance of the catalysts was discussed in terms of reduced species of vanadium oxide, prevailing on the catalysts, which increase the sulfone yield of refractory HDS compounds (DBT, 4-MDBT and 4,6-DMDBT).     

Study of a newly isolated thermophilic bacterium capable of Kuhemond heavy crude oil and dibenzothiophene biodesulfurization following 4S pathway at 60 °C

BACKGROUND: To meet stringent emission standards stipulated by regulatory agencies, the oil industry is required to bring down the sulfur content in fuels. As some compounds cannot be desulfurized by existing desulfurizing processes (such as hydrodesulfurization, HDS) biodesulfurization has become an interesting topic for researchers. Most of the isolated biodesulfurizing microorganisms are capable of desulfurization of refined products whose predominant sulfur species are dibenzothiophenes so biocatalyst development is still needed to desulfurize the spectrum of sulfur‐bearing compounds present in whole crude. RESULTS: The first desulfurizing bacterium active at 60 °C has been isolated, which reduces DBT concentration from 2 mmol L^?1 to 0.1 mmol L^?1 after 95 h, following the 4S pathway. Its DBT desulfurization pattern was represented by the Michaelis‐Menten equation. Various parameters such as V_max, K_m, µ_m, K_s and maximum specific DBT desulfurization rate were calculated which are 0.092 mmol L^?1 h^?1, 3.554 mmol L^?1, 0.157 h^?1, 3.722 mmol L^?1 and 0.192 mmol L^?1 DBT g^?1 DCW (dry cell weight) h^?1, respectively. It can desulfurize 50% of the sulfur content of Kuhemond heavy crude oil (KHC oil) with an initial sulfur content of 7.6%wt in 6 days. Its maximum specific desulfurization rate for KHC oil is equivalent to 0.005 g sulfur g^?1 DCW h^?1. The bacterium was isolated during a heavy crude oil biodesulfurization project initiated by PEDEC, a subsidiary of National Iranian Oil Company. CONCLUSION: The KHC oil sulfur removal efficiency of the bacterium is approximately five times that of BBRC‐9016 bacterium. It removes sulfur selectively without using sulfur‐containing compounds as its carbon source. By applying various media during its isolation, the probability of screening the correct microorganism is increased. Copyright © 2008 Society of Chemical Industry     

Bio‐Regeneration of Desulfurization Adsorbents by Selected P. delafieldii R‐8 Strains

Abstract

Adsorption properties of different adsorbents such as reduced NiY, AgY, alumina, 13X, and activated carbon were studied with dibenzothiophene (DBT) and naphthalene as model compounds. The desorption of DBT was carried on thermo gravimetric–differential thermal analysis (TG‐DTA). The interaction of DBT with different adsorbents follows the sequence: activated carbon > reduced NiY > AgY > activated alumina > 13X. The bio‐regeneration of these adsorbents was studied with P. delafieldii R‐8 as desulfurization strains. Adding P. delafieldii R‐8 cells can improve DBT desorption from adsorbent AgY. The desorption of DBT from adsorbents by bio‐regeneration of adsorbents follows the sequence: 13X > alumina > AgY > reduced NiY>activated carbon. The presence of naphthalene can decrease the desorption of sulfur compounds. The adsorption capacity of AgY decreases for the first time recycling and then changes little. The decrease of the adsorption capacity is due to the loss of Ag⁺ ions.     

Sensory Thresholds of Selected Phenolic Constituents from Thyme and their Antioxidant Potential in Sunflower Oil

The odor detection thresholds of carvacrol (5-isopropyl-2-methyl-phenol), thymol (2-isopropyl-5-methyl-phenol) and p-cymene 2,3-diol (2,3-dihydroxy-4-isopropyl-1-methyl-benzene) in sunflower oil, determined by the three-alternative, forced-choice procedure, were 30.97, 124 and 794.33 mg kg⁻¹, respectively. Sunflower oil containing 13, 70, or 335 mg kg⁻¹ of carvacrol, thymol or p-cymene 2,3-diol, respectively, was judged to be similar (P < 0.01) in taste and odor to its antioxidant-free counterpart. The rate constant of sunflower oil oxidation, measured from the increase in peroxide value during storage at 25 °C, was 9.2 × 10⁻⁹ mol kg⁻¹ s⁻¹ while the rate constants were 9.3 × 10⁻⁹, 9.8 × 10⁻⁹, and 4.3 × 10⁻⁹ mol kg⁻¹ s⁻¹ in the presence of 13 mg kg⁻¹ carvacrol, 70 mg kg⁻¹ thymol, and 335 mg kg⁻¹ p-cymene 2,3-diol, respectively. At a level of 335 mg kg⁻¹, p-cymene 2,3-diol did not impart flavor taints and effected a 46.7% reduction in the rate of oxidation of sunflower oil. These findings indicate that the diphenolic p-cymene 2,3-diol could potentially replace synthetic antioxidants and is a valuable addition to the antioxidants used by the food industry in its quest to meet consumer demands for synthetic-additives-free and ‘natural’ foods.     

Sulfided Mo and CoMo supported on zeolite as hydrodesulfurization catalysts: transformation of dibenzothiophene and 4,6-dimethyldibenzothiophene

The hydrodesulfurization (HDS) of dibenzothiophene (DBT) and of 4,6-dimethyldibenzothiophene (4,6-DMDBT) was carried out on sulfided Mo and CoMo on HY catalysts, and also on sulfided Mo and CoMo on alumina catalysts (fixed bed reactor, 330°C, 3 MPa hydrogen pressure). On all the catalysts, the two reactants transformed through the same parallel pathways: direct desulfurization (DDS) leading to biphenyl-type compounds, and desulfurization after hydrogenation (HYD) leading first to tetrahydrogenated intermediates, then to cyclohexylbenzene-type products. However, additional reactions were observed with the zeolite-supported catalysts, namely methylation of the reactants, cracking of the desulfurized products, and, in the case of 4,6-DMDBT, displacement of the methyl groups and transalkylation. The global activity of Mo/zeolite in DBT or 4,6-DMDBT transformation as well as its activity for the production of desulfurized products (HDS) were much higher than those of Mo/alumina. On the other hand, cobalt exerted a promoting effect on the activity in the transformation of DBT or 4,6-DMDBT of all the molybdenum catalysts. However, this effect was much less significant with the zeolite support than with the alumina support, which indicated that the promoter was not well associated to molybdenum on the zeolite support. Therefore, the activity of CoMo/zeolite in the HDS of DBT was much lower than that of CoMo/alumina. On the contrary, in the case of 4,6-DMDBT CoMo/zeolite was more active in HDS than CoMo/alumina. This increase in HDS activity was attributed to the transformation of 4,6-DMDBT into more reactive isomers through an acid-catalyzed methyl migration. The consequence was that on the zeolite-supported catalyst 4,6-DMDBT was more reactive than DBT.     

A simple unstructured model-based control for efficient expression of recombinant porcine insulin precursor by Pichia pastoris

Based on the fact that Pichia cell growth follows a Monod equation under the condition of methanol concentration limitation, a kinetics model of recombinant methylotrophic yeast Pichia pastoris expressing porcine insulin precursor (PIP) was developed in the quasi-steady state in the induction phase. The model revealed that the relationship between specific growth rate (μ) and substrate methanol concentration was in accord with the Monod equation. The fermentation kinetic parameters maximum specific growth rate (μ _max ), saturation constant (K _s ) and maintenance coefficient (M) were estimated to be 0.101 h⁻¹, 0.252 g l ⁻¹, and 0.011 g MeOH g⁻¹ DCW h⁻¹, respectively. The unstructured model was validated in methanol induction phase with different initial cell densities. Results showed that the maximum specific protein production rate (q _p.max ) of 0.098 mg g⁻¹ DCW h⁻¹ was achieved when μ was kept at 0.016 h⁻¹, and the maximum yield of PIP reached 0.97 g l ⁻¹, which was 1.5-fold as that of the control. Therefore, the simple Monod model proposed has proven to be a robust control system for recombinant porcine insulin precursor production by P. pastoris on pilot scale, which would be further applied on production scale. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

Activities of unsupported second transition series metal sulfides for hydrodesulfurization of sterically hindered 4,6‐dimethyldibenzothiophene and of unsubstituted dibenzothiophene

The applicability of transition metal sulfides (TMS) from the second transition series in deep hydrodesulfurization (HDS) was examined and compared to that of a traditional, supported CoMo/Al₂O₃ catalyst. Sulfides of Nb, Mo, Ru, Rh and Pd were studied for HDS of dibenzothiophene (DBT) and 4,6‐dimethyldibenzothiophene (4,6‐Me₂DBT). Measurements were carried out with unsupported TMS samples at different temperatures and H₂S partial pressures. The trend in DBT HDS activities agreed quite well with those found by previous authors. It was furthermore found that the activities of the metal sulfides towards the sterically hindered molecule 4,6‐Me₂DBT closely followed those for DBT. This is somewhat surprising since the direct sulfur abstraction route was of major importance for DBT while the prehydrogenation route, in which ring‐hydrogenation in the DBT skeleton precedes desulfurization, was prevalent for 4,6‐Me₂DBT. This suggests that common steps are involved in the two routes. For the unsupported metal sulfides, ring‐hydrogenated but not desulfurized DBT and 4,6‐Me₂DBT products were found in much larger amounts than for supported and promoted MoS₂‐based catalysts. This can be rationalized as being due to a relatively higher hydrogenation/desulfurization selectivity ratio for the different transition metal sulfides. Inhibition by H₂S was found to be most pronounced near the center of the transition series. This revised version was published online in July 2006 with corrections to the Cover Date.     

柴油深度加氢脱硫技术进展

随着世界各国对环保法规的日益关注,运输燃料深度脱硫技术在世界范围内受到广泛的研究。近年来,柴油深度脱硫化技术已受到西方国家的普遍重视。在工业上,加氢工艺是应对产品低硫化最有效的途径。柴油深度脱硫的关键是对反应活性最低的4,6-二甲基苯并噻吩类化合物中硫原子的脱除。本文综述了近年来柴油深度加氢脱硫技术的基本原理、超低硫柴油的催化及工艺的研究进展。     

Deep desulfurization by selective adsorption on a heteroatoms zeolite prepared by secondary synthesis

Gallium atoms have been introduced into the framework of Y zeolite by treating the zeolite with an aqueous solution of ammonium hexafluoro gallate. Desulfurization of various model fuels containing about 500 μg/g sulfur were studied over the synthesized Y zeolite ([Ga]AlY) with a liquid hourly space velocity of 7.2 h^− 1 at ambient conditions. The sulfur adsorption capacity was 7.0, 14.5, and 17.4 mg(S)/g adsorbent for thiophene, 4,6-dimethyldibenzothiophene (4,6-DMDBT), and tetrahydrothiophene (THT), respectively. The charges on S atom in thiophene, 4,6-DMDBT and THT, calculated by using density functional theory (DFT), are − 0.159, − 0.214 and − 0.298, respectively, implying that the S–M bond between the adsorption sites and thiophene is much weaker than that between the adsorption sites and THT or 4,6-DMDBT.     

Effect of the nitrogen heterocyclic compounds on hydrodesulfurization using in situ hydrogen and a dispersed Mo catalyst

The hydrodesulfurization (HDS) of the highly refractory sulfur-containing compounds, dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), and the effect of the basic and non-basic nitrogen heterocyclic compounds, such as quinoline and carbazole, on HDS using a dispersed unsupported Mo catalyst and in situ generated hydrogen were studied. Experimental results indicated that the dispersed unsupported Mo catalyst was effective for the HDS of 4,6-DMDBT in a mixture containing DBT. The direct desulfurization pathway (DDS) was the preferred pathway for the HDS of DBT while the hydrogenation pathway (HYD) was the preferred pathway for the HDS of 4,6-DMDBT under our experimental conditions. A strong inhibitive effect of the basic quinoline or the non-basic carbazole on the HDS of each of the sulfur-containing compounds was observed. The DDS and HYD pathways in the HDS of the refractory sulfur-containing compounds were affected to a different extent by the nitrogen-containing compounds, suggesting that different active sites were involved in these two reaction pathways.     

High performance sorbents for diesel oil desulfurization

Sorbents with different Ni loading supported on silica–alumina (SiAl) and activated carbon (AC) were synthesized and tested for removal of sulfur compounds from a model diesel oil, containing nearly 250 ppmw S as benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). A state-of-art Commercial Ni-based sorbent and two Norit activated carbons were also tested for comparison. Moreover, the influence on sorbents uptake capacity of the presence of aromatics in amounts representative of real diesel oils was studied. Both commercial and home-made materials performed worse in presence of aromatic compounds. Probably, the latter competed with the refractory sulfur compounds (DBT and 4,6-DMDBT) in the adsorption on active sites. As a first important result of the investigation the sorbents carrying 45% and 30% of Ni on SiAl showed a breakthrough uptake capacity of nearly, respectively, 2 and 2.6 times higher than Commercial sorbent as a consequence of their higher Ni dispersion and surface area. Moreover, activated carbons and the sample with 28%Ni on AC showed an even higher breakthrough uptake capacities. In particular, the deposition of nickel on activated carbon is an innovative approach which takes advantage of the selectivity of Ni towards S-species and the high adsorptive capacity of AC support.     

Chemical Composition and Oxidative Stability of Kernel Oils from Two Current Subspecies of Pistacia atlantica in Iran

Pistacia atlantica subsp. mutica (PAM) and kurdica (PAK) kernel oils showed significantly lower unsaturated to saturated fatty acid ratios (6.39, 6.33, respectively) and calculated oxidizability (Cox) values (3.99, 4.13, respectively) than those of the P. vera L. cv. Ohadi (PVO) kernel oil (8.91, 4.41) samples. The highest peroxide value was observed for the PAK oil (4.07 mequiv kg⁻¹) (PAM, 1.94; PVO, 0.37) samples. Iodine values for the PAM, PAK, and PVO oils were 104.26, 104.77, and 110.66, respectively. The saponification number of the PVO oil was significantly greater than the PAM and PAK oils, which were statistically not different. The unsaponifiable contents, which were composed mainly of sterols, ranged from 5.63 to 6.14%. Statistically the total tocopherols contents of the PAM (818.58 mg α-tocopherol kg⁻¹) and PVO (815.90 mg α-tocopherol kg⁻¹) oils were significantly higher than that of the PAK oil (499.91 mg α-tocopherol kg⁻¹). Total phenolics contents differed significantly, the greatest concentration was for the PAM oil (81.12 mg gallic acid kg⁻¹), followed by the PVO (62.84 mg gallic acid kg⁻¹) and PAK (56.51 mg gallic acid kg⁻¹) oil samples. The wax contents of the oil samples were statistically in the same range, namely 5.67–6.48%. Oxidative stability data indicated that the PAM oil is the most resistant to the formation of lipid oxidation products, followed by the PAK and PVO oil samples.     

Textural and chemical factors affecting adsorption capacity of activated carbon in highly efficient desulfurization of diesel fuel

Two synthetic, polymer-derived carbons, and two commercial carbons were investigated as adsorbents of dibenzothiophene and 4,6-dimethyldibenzothiophene from simulated diesel fuel in dynamic conditions. The total concentration of sulfur was 20 ppm. The surface features of the carbons were evaluated using adsorption of nitrogen, potentiometric titration, Boehm titration, thermal analysis and FTIR. The polymer-derived carbons outperformed the commercial micro- and micro/mesoporous carbons from the point of view of adsorption capacity and selectivity. The latter was evaluated based on the adsorption of naphthalene, which was also present in the fuel used. It was found that the presence of arenes did not affect significantly the capacity measured. The results suggest that the amount adsorbed is mainly governed by the volume of micropores, where dispersive interactions are predominant. Acidic groups located in larger pores are also important to attract additional molecules DBT and 4,6-DMDBT via specific interactions with the progress of adsorption. These groups may also contribute to the reactive adsorption leading to oxidation of DBT and 4,6-DMDBT.     

Physico-Chemical Characterization of <Emphasis Type="Italic">Moringa concanensis</Emphasis> Seeds and Seed Oil

The present work reports the characterization and comparison of Moringa concanensis seed oil from Tharparkar (a drought hit area), Pakistan. The hexane-extracted oil content of M. concanensis seeds ranged from 37.56 to 40.06% (average 38.82%). Protein, fiber, moisture and ash contents were found to be 30.07, 6.00, 5.88 and 9.00%, respectively. The extracted oil exhibited an iodine value of 67.00; a refractive index (40 °C) of 1.4648; its density (24 °C) was 0.8660 mg mL⁻¹; the saponification value (mg of KOH g⁻¹ of oil) was 179.00; unsaponifiable matter 0.78%; color (1 in. cell) 1.90R + 19.00Y; and acidity (% as oleic acid) 0.34%. Tocopherols (α, γ, and δ) in the oil accounted for 72.11, 9.26 and 33.87 mg kg⁻¹, respectively. Specific extinctions at 232 and 270 nm were 3.17 and 0.65, respectively. The peroxide and p-anisidine values of the oil were found to be 1.75 and 1.84 meq kg⁻¹, respectively. The induction periods (Rancimat, 20 L h⁻¹, 120 °C) of the crude oil was 10.81 h and reduced to 8.90 h after degumming. The M. concanensis oil was found to contain high levels of oleic acid (up to 68.00%) followed by palmitic, stearic, behenic, and arachidic acids up to levels of 11.04, 3.58, 3.44 and 7.09%, respectively. The results of the present analytical study, compared with those for other Moringa species and different vegetable oils, showed M. concanensis to be a potentially valuable non-conventional seed crop for high quality oil.     

Deep oxidative–extractive desulfurization of fuels using benzyl‐based ionic liquid

Four benzyl‐based ionic liquids (ILs) were synthetized and used for deep desulfurization of model oil and real diesel fuel. The removal efficiencies of benzothiophene (BT) and dibenzothiophene (DBT) with [Bzmim][NTf₂] and [Bzmim][SCN] as extractants are higher than that with [Bzmp][NTf₂] and [Bzmp][SCN] as extractants. The desulfurization capability follows the Nernst's Law. A reactive extraction mathematical model for desulfurization was established. An oxidative‐extractive two‐step deep desulfurization method was developed. DBT was first oxidized by H₂O₂ with CH₃COOH as catalyst and then the unoxidized DBT and uncrystallized dibenzothiophene sulfoxide (DBTO₂) in model oil were extracted by [Bzmim][NTf₂], and finally the removal efficiency was 98.4% after one‐stage extraction. Besides, the removal efficiency of 4,6‐DMDBT was 96.4% after oxidation and one‐stage extraction processes. Moreover, the oxidative‐extractive two‐step deep desulfurization method was also effective for desulfurization of diesel fuel. The removal efficiency of sulfur reached up to 96% after oxidation and three‐stage cross‐current extraction processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4023–4034, 2016