Desulfurization Of Oil Research Articles

Recycle Performance of Heterogeneous Catalyst Metal Oxides-Based Layered Double Hydroxide for Oxidative Desulfurization Process of 4-methyldibenzothiophene

The desulfurization of oil must be resolved as soon as possible due to a variety of issues, including environmental contamination and protection regulations. It was believed that oxidative desulfurization (ODS) was the most promising method. In this research, metal oxide-based layered double hydroxides (TiO2@Ni-Al and ZnO@Ni-Al) were effectively synthesized for the ODS of 4-methyldibenzothiophene (4-MDBT). TiO2@Ni-Al and ZnO@Ni-Al exhibited superior catalytic performance and high recycling capacity, achieving a 99% removal rate after five reactions in 30 min. The heterogeneous catalyst TiO2@Ni-Al/ZnO@Ni-Al is easy to separate and recover from a reaction system. Increased temperature facilitates the transformation of 4-MDBT into 4-MDBTO2. The influence of H2O2's rapid decomposition rate, which can inhibit oxidation reactions, reduces the catalytic activity as the temperature increases. 4-MDBT Sulphur removal on TiO2@Ni-Al and ZnO@Ni-Al is 99.48 and 99.51%, respectively. TiO2@Ni-Al and ZnO@Ni-Al have great potential for use in the industry based on these results. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

A deep-insight into the relation between structure of graphene oxide-based interfacial catalyst and fuel oil desulfurization performance in Pickering emulsion

Based on the high stability, easy demulsification and formed large interphase contact area of the Pickering emulsion, its corresponding catalytic oxidative desulfurization (CODS) system has exhibited satisfactory desulfurization results and recycling performance. However, the relation between the interfacial catalyst structure and desulfurization performance in Pickering emulsion systems has rarely been reported. Herein, a stable Pickering emulsion CODS system was established using H3PW12O40 (HPW)-supported graphene oxide (GO) as an interfacial catalyst. Some important structural parameters, including catalyst size, surface porosities and wettability, were adjusted, and their effect on desulfurization performance was analysed in detail. Additionally, the reaction conditions, selectivity and recyclability of the studied system were systematically evaluated. The small catalyst size and high surface porosities could facilitate mass reaction transfer to improve desulfurization performance, but the effect of wettability was most prominent. The Pickering emulsion formed by the amphiphilic catalyst exhibited the optimum distribution state of emulsion droplets with an enlarged interphase contact area. After the optimized design of the catalyst structure, ultradeep fuel oil desulfurization was achieved under mild conditions without stirring. This work provides a useful reference to further mine the mechanism behind the improvement of desulfurization performance in Pickering emulsion systems.

Designing flower-like La-Bi2WO6/Ni@N-rGO composite for the photocatalytic oxidation coupled in-suit hydrogenation desulfurization of diesel oil

The ultra-deep removal of 4,6-DMDB and decrease in loss of C/ H atoms is one of the bottlenecks in achieving ultra-low sulfur fuel oil, which is resolved with photocatalytic oxidation coupled with in-situ hydrodesulfurization. Herein, a flower cluster microsphere composite La-Bi2WO6/Ni@N-rGO as photocatalytic oxidation coupling with in-situ hydrodesulfurization catalysts was prepared by a one-step hydrothermal method. The characterization results of STEM, SEM, Raman, and XPS showed that La-Bi2WO6 combined with Ni@N-rGO formed flower-like microspheres with large specific surface areas. The experimental results showed that the catalysts had excellent photocatalytic oxidation coupling with in-situ hydrodesulfurization performance and good stability. A desulfurization ratio of 4,6-DMDBT reached 99.9% under mild conditions. A plausible mechanism for the photocatalytic desulfurization of 4,6-DMDBT was presumed by combining experiments with density functional theory. The designed La-Bi2WO6/Ni@N-rGO could be utilized for a large-scale process of diesel and other transpiration fuel oil.

Ultrasound oxidative desulfurization of petroleum gas oil using phosphotungstic acid/ZnAl calcined LDH as efficient and recoverable nanocomposite

The combination of unique characteristics of phosphotungstic acid (PTA) and calcined ZnAl layered double hydroxides (CLDHs) are predicted to make use of innovative catalysts with enhanced catalytic activity. The structure of the fabricated PTA/ ZnAl CLDH composite was determined by a series of characterizations using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman, nitrogen adsorption–desorption isotherm, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analysis. PTA/ZnAl CLDH composite was employed as an efficient catalyst in ultrasound- oxidative desulfurization (UODS) of gas oil (sulfur content 22,174 ppm). UODS was evaluated at different parameters like times, temperatures of ultrasonic bath, amount of oxidant, catalyst dose and different extracting agent. All desulfurization reactions were carried out with environmentally friendly H2O2 as oxidizing agent. The prepared composite achieved high desulfurization effectiveness (91.2 %) within 1 h at optimum conditions. The UODS mechanism was clarified. PTA/ ZnAl-CLDH catalyst revealed remarkable stability and regeneration capabilities after six consecutive recycles with negligible activity loss.

Deep oxidative desulfurization of gas oil by iron(III)-substituted polyoxometalate immobilized on nickel(II) oxide, ((n-C4H9)4N)4H[PW11FeO39]@NiO, as an efficient nanocatalyst

Sulfur compounds are among the most unfavorable constituents of petroleum derivatives, so stringent regulations have been established to curb their atmospheric emissions. In this regard, a new nanocomposite ((n-C4H9)4N)4H[PW11FeO39]@NiO) was synthesized composed of quaternary ammonium bromide salt of ironIII-substituted Keggin-type polyoxometalate immobilized on nickel(II) oxide nanoceramics via sol–gel method. The assembled (n-C4H9)4N)4H[PW11FeO39]@NiO nanocomposite was identified by FT-IR, UV–Vis, XRD, SEM, EDX, and TGA-DTG methods. The characterization results exhibited that ((n-C4H9)4N)4H[PW11FeO39] dispersed uniformly over the surface of the NiO nanoceramics. The ((n-C4H9)4N)4H[PW11FeO39]@NiO nanocomposite was employed as a heterogeneous nanocatalyst in the extractive coupled oxidation desulfurization (ECOD) of real gas oil and dibenzothiophene (DBT) as a model compound. Under relatively moderate conditions, the catalytic performance of the ((n-C4H9)4N)4H[PW11FeO39]@NiO in the ECOD procedure was studied by incorporating acetic acid/hydrogen peroxide as an oxidant system at a volume ratio of 1:2. According to the ECOD results, the ((n-C4H9)4N)4H[PW11FeO39]@NiO demonstrated the effectiveness of up to 95% with 0.1 g at 60 °C under optimal operating conditions. Moreover, the ((n-C4H9)4N)4H[PW11FeO39]@NiO nanocatalyst could be separated and reused for five runs without a noticeable decrease in the ECOD process. This study provides a promising way to meet the target of ultra-low sulfur as an essential process in oil refineries.

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.

Thermochemical Upgrading of Heavy Crude Oil in Reservoir Conditions

The purpose of this study is to enhance the quality of heavy oil through refinement using aquathermolysis with the simultaneous injection of steam and thermally stable nonionic surfactants (NS). To achieve this, the NS R-PPG of the nonionic type was synthesized, and the optimal product structures were characterized using infrared (IR) methods. Furthermore, the thermal stability of the synthesized NS R-PPG was investigated in line with the requirements for surfactants used in heavy oil applications. Subsequently, the study delved into investigating the hydrothermal upgrading of heavy oil with a catalyst, involving the joint participation of steam and surfactants at a temperature of 250 °C. Additionally, we assessed the improved oil characteristics resulting from the experimental process through SARA analysis, elemental analysis, GC, and viscosity reduction evaluations. The experimental results demonstrated distinct effects concerning the presence and absence of surfactants on heavy oil. Based on these findings, we conclude that surfactants play a crucial role in dispersing asphaltene clusters, thereby facilitating the decomposition process under mild thermobaric conditions, leading to a noticeable increase in the content of light fractions. Furthermore, as per the results of the elemental analysis, surfactants contribute significantly to the desulfurization of heavy oil. Overall, the incorporation of surfactants during hydrothermal upgrading resulted in an irreversible reduction in the viscosity of heavy oil, thereby enhancing its overall quality.

Green Copper Carbonate Nanoparticles Produced by the Ureolytic Fungus Alternaria sp. Strain ccf7 and Their Antibacterial Activity

Background: Copper carbonate nanoparticles have several applications in the fields of pigments, insecticides, and fungicides. They are also used as catalysts in chemical processes and crude oil desulfurization. Fungi can biosynthesize metal nanoparticles due to their high tolerance, extracellular synthesis, simplicity of extraction, and large-scale exploitation. Objectives: This study aimed to investigate the potential of fungal isolates (which are resistant to copper chloride with urease activity) as biocatalysts for the synthesis of copper carbonate nanoparticles. This approach was considered due to the advantages of using fungal isolates in nanoparticle biosynthesis. Methods: In a PDA culture medium with 25 mM copper chloride, an enrichment culture was used to isolate copper-resistant fungal isolates. Fungal isolates’ urease enzyme was qualitatively assessed using 2% urea agar-based culture media. Studies on the synthesis of copper carbonate nanoparticles and the effect of different parameters on the synthesis of these nanoparticles were conducted using a mycelium-free supernatant strategy. Field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) studies were used to determine the properties of calcium carbonate nanoparticles. The selected fungal isolate was identified using macroscopic and microscopic characteristics, as well as molecular analysis using amplification of the ITS1-5.8S-ITS2 gene sequences. Results: Alternaria sp. strain ccf7 (GenBank accession number OP242500) was chosen as the superior strain for copper carbonate nanoparticle synthesis tests based on the pattern of resistance to copper chloride salt and the qualitative assessment of urease activity. Based on the findings of the electron microscope studies, spherical copper carbonate nanoparticles with an average size of 66.7 nm were synthesized after 24 hours of incubation at the optimal concentration of 45 mM copper chloride, temperature of 25°C, and shaker speed of 100 rpm. The distribution of the produced nanoparticles was appropriate, as indicated by a polydispersity index (PDI) of 0.25. The strongest inhibitory impact of these copper carbonate nanoparticles was against Pseudomonas aeruginosa, with an average inhibition of 31 mm at a concentration of 50 mg/L, according to the results of their antibacterial activities. Conclusions: For the first time, the synthesis and development of a green approach for the fabrication of copper carbonate nanoparticles using the genus Alternaria have been proposed in this study.

Synergetic ultrasound assisted catalytic oxidative extractive desulfurization of tire pyrolysis oil employing sustainable protic deep eutectic solvents

One-pot ultrasound-assisted selective oxidative extractive desulfurization (UA-SOEDS) of tire pyrolysis oil (TPO) was carried out with sustainable protic deep eutectic solvent (pDES) synthesized with quaternary ammonium salts as HBA and organic acids as HBD. The Tetrabutyl ammonium chloride and malic acid-based pDES with moderate viscosity resulted in a maximum Sulphur removal of (92.6 % (w/v)). A central composite design-based optimization of essential variables (US time (12 min), US temperature (333.15 K), US power (1.2 kW) and pDES/TPO ratio (22.5 % v/v)) was carried out resulting in an effective sulfur removal rate of (93.6% w/w). The pDES post extraction was recovered with the addition of isooctane and reused for consecutive cycles of UA-SOEDS process, loosing its characteristic oxidative extraction property after 3rd cycle (68.53%). The chromatographic analysis confirmed the presence of long-chain hydrocarbons in the oxidized TPO which confirms its property as a good fuel. The physicochemical properties and the calorific value of the resulting base oil were determined making it a suitable candidate as an alternative green fuel meeting the international standards of soluble Sulphur.

Desulfurization of Crude Oils, Diesels, and Oil Fractions by Treatment with Ozone and Metal Chlorides

West Siberian crude oils from the Samotlorskoye oil field, diesel fractions, and I-20A industrial oil were desulfurized with metal chlorides (ZnCl2, FeCl3, and AlCl3) and with a reagent complex (formulation) consisting of 70 wt % AlCl3, 25 wt % oxygenated diesel fuel, and 5 wt % NaOH. Purification of a mixed diesel fraction with an AlCl3 + NaOH (at a weight ratio of 10 : 1) formulation reduced the sulfur content in the diesel mixture from 0.82 to 0.146%. When purifying I-20A with a formulation at a weight ratio of 1 : 1, the sulfur content in the oil decreased from 0.2 to 0.03%. When the West Siberian crude oil (in which organosulfur compounds had been pre-oxygenated by an ozone–oxygen mixture into sulfoxides and sulfones) was purified with a formulation at a weight ratio of 20 : 1, the sulfur content was reduced from 1.8 to 0.5 wt %. The spent formulation was disposed of by introduction into bitumen.

Waste rubber-modified sulfur-fly ash-sand composites as low CO2-emission cements

The by-product of oil desulfurization, sulfur, can be used as an eco-friendly material to replace cement. In this study, waste rubber-modified sulfur-fly ash-sand composites (WRMSFSC) were prepared by waste rubber, modified sulfur, fly ash, and sand. The effect of percentage of modified sulfur and waste rubber on the mechanical properties of WRMSFSC were investigated. The pore size distribution, mineralogy phases, microstructure, and thermal properties of WRMSFSC were characterized by NMR, XRD, FTIR, SEM, and DSC. Results indicated that the compressive and flexural bonding strength of WRMSFSC were enhanced with the increase of modified sulfur content. The flexural bonding strength of WRMSFSC containing only 2% of waste rubber increased by approximately 48.34%. Microscopic results showed that the number of macropores (>1 μm) and capillary pores (0.1–1 μm) in WRMSFSC were significantly reduced with the increase of modified sulfur content. The pore structure characteristic parameters were used to explain the mechanical properties of WRMSFSC. Analysis of the mechanical properties of WRMSFSC by response surface methodology (RSM) showed that the optimum modified sulfur and waste rubber content was 30% and 2%.

Aquathermolysis of Heavy Crude Oil: Comparison Study of the Performance of Ni(CH3COO)2 and Zn(CH3COO)2 Water-Soluble Catalysts

Aquathermolysis is one of the crucial processes being considered to successfully upgrade and irreversibly reduce the high viscosity of heavy crude oil during steam enhanced oil recovery technologies. The aquathermolysis of heavy oil can be promoted by transition metal-based catalysts. In this study, the catalytic performance of two water-soluble catalysts Ni(CH3COO)2 and Zn(CH3COO)2 on the aquathermolytic upgrading of heavy oil at 300 °C for 24 h was investigated in a high pressure–high temperature (HP-HT) batch reactor. The comparison study showed that nickel acetate is more effective than zinc acetate in terms of viscosity reduction at 20 °C (58% versus 48%). The viscosity alteration can be mainly explained by the changes in the group composition, where the content of resins and asphaltenes in the upgraded heavy crude oil sample in the presence of nickel catalyst was reduced by 44% and 13%, respectively. Moreover, the nickel acetate-assisted aquathermolysis of heavy oil contributed to the increase in the yield of gasoline and diesel oil fractions by 33% and 29%, respectively. The activity of the compared metal acetates in hydrogenation of the crude oil was judged by the results of the atomic H/C ratio. The atomic H/C ratio of crude oil upgraded in the presence of Ni(CH3COO)2 was significantly increased from 1.52 to 2.02. In addition, the catalyst contributed to the desulfurization of crude oil, reducing the content of sulfur in crude oil from 5.55 wt% to 4.51 wt% The destructive hydrogenation of resins and asphaltenes was supported by the results of gas chromatography-mass spectroscopy (GC-MS) and Fourier-transform infrared (FT-IR) spectroscopy analysis methods. The obtained experimental results showed that using water-soluble catalysts is effective in promoting the aquathermolytic reactions of heavy oil and has a great potential for industrial-scale applications.

Synthesis of nanofluids composed of deep eutectic solvents and metal-modified MCM-41 particles as multifunctional promoters for fuel oil desulfurization

Synthesis of nanofluids composed of deep eutectic solvents and metal-modified MCM-41 particles as multifunctional promoters for fuel oil desulfurization

Two-Stage Sequential Adsorption System for Denitrogenation and Desulfurization of Model Diesel Oil over Ion-Exchanged Y Zeolites

This work focused on adsorptive desulfurization (ADS) and denitrogenation (ADN) in single- and two-stage systems. Na-Y zeolite possessed the best 4,6-DMDBT and DBT adsorption performances. La-Y zeolite exhibited the best ADN efficiency. The impact of nitrogen compounds and aromatics on ADS capacity and the impact of sulfur compounds and aromatics on ADN ability over ion-exchanged Y zeolite were evaluated in the single-stage system. The nitrogen compounds not only have the ability to compete, but they also have a higher absorbability than sulfur compounds. The sequential adsorption in a two-stage system was proposed to enhance ADS ability. The first stage contained La-Y for ADN, and the second stage contained Na-Y for ADS. It was found to successfully increase the breakthrough capacity of all compounds by 40% compared with the single-stage system. This two-stage sequential system is a suitable route for the elimination of sulfur and nitrogen content in diesel oil.

Desulfurization of Crude Oils, Diesels, and Oil Fractions by Treatment with Ozone and Metal Chlorides

Desulfurization of Crude Oils, Diesels, and Oil Fractions by Treatment with Ozone and Metal Chlorides

Facile synthesis of efficient pentaethylenehexamine-phosphotungstic acid heterogeneous catalysts for oxidative desulfurization

The ultra-deep desulfurization of oil needs to be solved urgently due to various problems, including environmental pollution and environmental protection requirements. Oxidative desulfurization (ODS) was considered to be the most promising technology. The facile synthesis of highly efficient and stable HPW-based heterogeneous catalysts for oxidative desulfurization is still a challenging task. In this paper, pentamethylene hexamine (PEHA) and phosphotungstic acid (HPW) were combined by a simple one-step method to prepare a heterogeneous catalyst of PEHA-HPW for the production of ultra-deep desulfurization fuel oil. The composite material exhibited excellent catalytic activity and high recyclability, which could reach a 100% dibenzothiophene (DBT) removal rate in 30 min and be recycled at least 5 times. Experiments and DFT simulations were used to better examine the ODS mechanism of PEHA-HPW. It was proved that the rich amino groups on the surface of PEHA-HPW play a crucial role. This work provides a simple and feasible way for the manufacture of efficient HPW-based catalysts.

A comprehensive process optimization study of the mixing assisted oxidative desulfurization of diesel oil

In the aspect of oils derived from fossil fuel, it is vital to remove high sulfur concentrations via the desulfurization technique before its combustion. In this study, a comprehensive process optimization analysis for the mixing assisted oxidative desulfurization (MAOD) that undertakes a process intensification method by a high shear mixer and the simultaneous application of the sodium phosphotungstate/hydrogen peroxide (NaPW/H2O2) system were examined for the treatment of a raw diesel sample. The response surface methodology via Box–Behnken design for the method of MAOD was employed to examine the parametric influences of sulfur conversion by the independent variables of mixing time (6 min to 30 min), NaPW dose (10 mg to 500 mg), H2O2 concentration (30 %v/v to 50 %v/v), and reaction temperature (30 °C to 70 °C). The investigation of the level of significance in the individual process variable and its respective interactive effects were investigated through an analysis of variance. The results indicated that the process variables of mixing time, NaPW dosage, and reaction temperature has high statistical significance (p-value < 0.0001). The mean optimum sulfur conversion of 96.6 % for the raw diesel samples has been attained after three confirmatory runs at 29.6 min, 471.4 mg NaPW, 44.4 %v/v H2O2, and 62.8 °C. Therefore, the results obtained in this research demonstrated the novel application of MAOD as the desulfurization technique to treat raw diesel. This validates a promising result for the application of MAOD as a prospective methodology for future applications.

Novel Gemini ionic liquid for oxidative desulfurization of gas oil

The N1,N1,N3,N3-tetramethyl –N1,N3-diphenylpropane-1,3-diaminium dichloride ionic liquid (ILc) is an environmentally friendly catalyst for oxidative–extractive desulfurization of gas oil (sulfur content = 2400 ppm) in the presence of H2O2 as an oxidizing agent. The precise structure of the prepared IL was confirmed using FT-IR spectroscopy, and1H-NMR. The reaction temperature, IL ratios, H2O2 dosage, and reaction time were studied to assess their effects on the desulfurization efficiency. The thermodynamic parameters of the oxidation reaction were determined. A desulfurization efficiency of 84.7% was obtained after the extractive desulfurization process using acetonitrile as an organic solvent at a solvent to feed ratio of 1:1 (v/v). Furthermore, the prepared IL may be reused for at least six cycles without any significant change in its desulfurization performance or chemical structure, which confirms its high reusability.

Bio-catalytic degradation of dibenzothiophene (DBT) in petroleum distillate (diesel) by Pseudomonas spp.

Biodesulfurization (BDS) was employed in this study to degrade dibenzothiophene (DBT) which accounts for 70% of the sulfur compounds in diesel using a synthetic and typical South African diesel in the aqueous and biphasic medium. Two Pseudomonas sp. bacteria namely Pseudomonas aeruginosa and Pseudomonas putida were used as biocatalysts. The desulfurization pathways of DBT by the two bacteria were determined by gas chromatography (GC)/mass spectrometry (MS) and High-Performance Liquid Chromatography (HPLC). Both organisms were found to produce 2-hydroxy biphenyl, the desulfurized product of DBT. Results showed BDS performance of 67.53% and 50.02%, by Pseudomonas aeruginosa and Pseudomonas putida, respectively for 500 ppm initial DBT concentration. In order to study the desulfurization of diesel oils obtained from an oil refinery, resting cells studies by Pseudomonas aeruginosa were carried out which showed a decrease of about 30% and 70.54% DBT removal for 5200 ppm in hydrodesulfurization (HDS) feed diesel and 120 ppm in HDS outlet diesel, respectively. Pseudomonas aeruginosa and Pseudomonas putida selectively degraded DBT to form 2-HBP. Application of these bacteria for the desulfurization of diesel showed promising potential for decreasing the sulfur content of South African diesel oil.

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.