Desulfurization Of Model Oil Research Articles

Denitrogenation and desulfurization of model oil through adsorption process using one-pot-synthesized reusable CYCU-3@Al2O3 composites

The as-synthesized CYCU-3@Al2O3 composites were used for the removal of SCCs and NCCs from model oil and showed excellent adsorption performances and recyclability.

Adsorptive Desulfurization of Model Oil by Ag nanoparticles-modified Eichhornia crassipes: Equilibrium, Kinetics, and Thermodynamic Studies

Adsorptive Desulfurization of Model Oil by Ag nanoparticles-modified Eichhornia crassipes: Equilibrium, Kinetics, and Thermodynamic Studies

Deep desulfurization of model oil using green amino acid ionic liquids combined with H2O2

The sulfur compounds in diesel can cause environmental pollution. As the main component of the sulfide compounds in diesel, dibenzothiophene (DBT) must be removed previously. In this study, 1-alkyl-3-methyl imidazole ionic liquids (ILs) bromic [C n mim]Br (n = 4, 6, 8, 12) were prepared. The phenylalanine, histidine, glycine, tryptophan were used as anions to displace the Br−1 of [C n mim]Br through ion exchange resin to get the amino acid ionic liquids for deep removal of DBT from model oil in the presence of H2O2. The results show that the desulfurization of 1-octyl-3-methyl phenylalanine imidazole ionic liquid [C8mim]Phe is higher than that of [C8mim]His, [C8mim]Gly, and [C8mim]Trp. The effect of temperature, the volume ratio of H2O2/model oil, and time on desulfurization of [C8mim]Phe combined with H2O2 was studied. The response surface analysis was used to seek the optimal desulfurization process parameters of the [C8mim]Phe combined with H2O2. Repeated experiments of DBT removal by [C8mim]Phe combined with H2O2 from model oil were conducted under the optimized conditions. The desulfurization of [C8mim]Phe combined with H2O2 was declined from 97.4% to 93.4% after 8 recycle times. Meanwhile, the oxidation-extraction desulfurization mechanism of [C8mim]Phe combined with H2O2 was confirmed by Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography-mass spectrometry (LC-MS).

Desulfurization of Model Oil through Adsorption over Activated Charcoal and Bentonite Clay Composites

AbstractAdsorption of dibenzothiophene (DBT) from model oil was investigated using composites of pure activated charcoal and pure bentonite clay. DBT adsorption was carried out in batch mode experiments at laboratory scale, where the developed composite materials showed a synergistic effect in removal of DBT from the model oil in terms of improved surface acidity of the pure activated charcoal and mesoporous structure of the pure bentonite clay. Thermodynamics, kinetics, and optimization of various adsorption parameters were investigated. Kinetic analyses proved that DBT adsorption followed pseudo‐second‐order kinetics. To study the thermodynamics of the adsorption, different isotherm adsorption models were applied. The Langmuir isotherm best fitted to the adsorption data. Various thermodynamic parameters were evaluated, including Gibbs free energy, entropy, and enthalpy.

Ultra-deep removal of thiophene from model oil, catalyzed by amphiphilic ionic liquids in reverse micellar system

Amphiphilic imidazolium ionic liquids have been successfully applied in desulfurization of model oil. The reduction of thiophene content to below 1 ppm was achieved. Dual functionality of ILs used in this study allows to form the reactive reverse micellar system and to catalyze oxidation of thiophene into oxidation products effectively. A molecular interaction of H2O2 molecule with imidazolium C2H proton may be considered as a one of the key factor of desulfurization process carried out in reverse micellar system catalyzed by imidazolium ILs. Furthermore, observed catalytic synergism of imidazolium ILs and H2SO4 also affects the high efficiency of this process.

Catalytic Oxidative/Extractive Desulfurization of Model Oil using Transition Metal Substituted Phosphomolybdates-Based Ionic Liquids

Polyoxometalates based ionic liquids (POM-ILs) exhibit a high catalytic activity in oxidative desulfurization. In this paper, four new POM-IL hybrids based on transition metal mono-substituted Keggin-type phosphomolybdates, [Bmim]5[PMo11M(H2O)O39] (Bmim = 1-butyl 3-methyl imidazolium; M = Co2+, Ni2+, Zn2+, and Mn2+), have been synthesized and used as catalysts for the oxidation/extractive desulfurization of model oil, in which ILs are used as the extraction solvent and H2O2 as an oxidant under very mild conditions. The factors that affected the desulfurization efficiency were studied and the optimal reaction conditions were obtained. The results showed that the [Bmim]5[PMo11Co(H2O)O39] catalyst demonstrated the best catalytic activity, with sulfur-removal of 99.8%, 85%, and 63% for dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and benzothiophene (BT), respectively, in the case of extraction combining with a oxidative desulfurization system under optimal reaction conditions (5 mL model oil (S content 500 ppm), n(catalyst) = 4 μmol, n(H2O2)/n(Substrate) = 5, T = 50 °C for 60 min with [Omim]BF4 (1 mL) as the extractant). The catalyst can be recycled at least 8 times, and still has stability and high catalytic activity for consecutive desulfurization. Probable reaction mechanisms have been proposed for catalytic oxidative/extractive desulfurization.

The confined space electron transfer in phosphotungstate intercalated ZnAl-LDHs enhances its photocatalytic performance for oxidation/extraction desulfurization of model oil in air

Synergetic interaction between phosphotungstate and hydrotalcites in confined space enhances electron transfer and photo catalytic oxidation of DBT.

Desulfurization of Model Oil by Selective Adsorption over Porous Boron Nitride Fibers with Tailored Microstructures

We report on the controllable synthesis of porous BN microfibers and explore their applications as adsorbent for removing dibenzothiophene (DBT) in model oil. The growth evolution of porous BN microfibers has been carefully investigated by correlating their structural characteristics with their synthesis conditions. The as-prepared BN microfibers exhibit very high adsorption capacity for DBT (86 mg S g−1 according to the Langmuir isotherm model), showing excellent adsorptive desulfurization performance. The porous BN after adsorption can be regenerated by a simply heat treatment. After four times recycling, the regenerated adsorption capacity still remains more than 83% of that at the first adsorption. The superb oxidation resistance and chemical inertness, high sulfur adsorption capacity, as well as excellent regeneration performance render the developed porous BN microfibers to be a decent adsorbent for sulfur removal from fuels.

Photo Oxidative Extractive Desulfurization of Model Oil Using Fe/TiO<sub>2</sub> Photocatalyst and Eutectic Based Ionic Liquid: Effect of Metal Loading

Titanium dioxide (TiO2) photocatalyts doped with iron metal at different metal loadings were successfully prepared and characterized. The doped photocatalyst were characterized using diffuse reflectance spectroscopy (DR-UV-Vis), X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM).Photooxidative extractive desulfurization of model oil containing dibenzothiophene as the sulfur compound (100ppm) was investigated using the prepared photocatalyst. The photocatalyst with 0.20 wt% Fe metal loading showed the best sulfur removal at 61.13%.

Deep extractive desulfurization of oil over 12-molibdophosphoric acid encapsulated in metal-organic frameworks

A desulfurization process for model oil and real oil was investigated based on the chemical oxidation of mixed sulfur containing compounds in the presence of nitrogen compounds (indole and quinoline) using hydrogen peroxide as oxidizing agent and dodecamolibdophosphoric acid (H3PMo12O40) encapsulated in a kind of metal-organic framework (HKUST-1) as PMo@HKUST-1. The effect of isopropanol, ethanol and acetonitrile as extractive solvent and 1-ring (toluene, xylene and mesitylene) and 2-ring (naphthalene) aromatic hydrocarbons in desulfurization of model oil was studied. The desulfurization of sulfur-containing compounds was accelerated in the presence of aro- matic hydrocarbons. In fact, a higher desulfurization efficiency of the heterogeneous catalyst could be achieved with system containing a polar solvent in contact with an aromatic hydrocarbon. Quinoline had no effect on oxidative desulfurization (ODS) reaction, whereas indole had a slightly negative effect. Presence of aromatic compounds had slightly positive effect on ODS reaction.

Deep Desulfurization of Model Oil by Extraction with a Low-viscosity Ionic Liquid [BMIM]SCN

In this work, a low-viscosity ionic liquid 1-buthyl-3-methylimidazole thiocyanate ([BMIM]SCN) was utilized as extractant for the extractive desulfurization of thiophene in model oil. Several conditions were investigated respectively, including extraction time, temperature, and volume ratio of ionic liquid to model oil. Also the kinetics of extraction of thiophene were proposed. Under the optimal extractive conditions, the removal of thiophene in model oil was 55.6%. Other sulfur compounds and real oil were also investigated. Furthermore, the total desulfurization efficiency could reach 98.3%. In addition, the ionic liquid could be recycled seven times with negligible decrease in activity.

Efficient Oxidative Desulfurization of Model Oil at Room Temperature with Ionic Liquid as Extraction Solvent

The oxidative desulfurization of model oil (hexane solution of thiophene) was carried out at room temperature in a two-step method involving: 1) the acetic acid catalyzed oxidation of thiophene with hydrogen peroxide and 2) the subsequent extraction of the oxidized products with three 1-alkyl-3-methylimidazolium bromide [RMIM]Br ionic liquids of varying alkyl substituent R chain length (R: C2, C4, C6) and with acetonitrile as control. For purposes of comparison, a non-oxidative extractive desulfurization of model oil with the above ionic liquid and with acetonitrile was also performed. The thiophene extraction efficiencies of the ionic liquids and that of the control in both the oxidative and non-oxidative procedures were determined by means of gas chromatography. The ionic liquid of the shortest alkyl substituent chain length (R: C2), [EMIM] Br exhibited the highest extraction efficiency in the oxidative desulfurization of the model oil; the extraction efficiency of [EMIM] Br was also observed to exceed that of acetonitrile. In general, the oxidative desulfurization with the above [RMIM]Br’s is apparently a more efficient method of thiophene removal from the model oil as compared to a non-oxidative procedure with the same extraction solvents. The extraction efficiency of [RMIM]Br’s was observed to decrease with the lengthening of the alkyl substituent chain. The same trend is observed in the non-oxidative extractive desulfurization of the model oil. Recyclability analysis of [EMIM]Br showed that [EMIM]Br can be recycled thrice with no significant decrease in extraction efficiency.

Deep Desulfurization of Fuels by Heteropolyanion-Based Ionic Liquid

A new heteropolyanion-based ionic (<TEX>$[Hmim]_5PMo_{10}V_2O_{40}$</TEX>) was synthesized by the reaction of molybdovanadophosphoric acid (<TEX>$H_5PMo_{10}O_{40}$</TEX>) with N-methylimidazole. [<TEX>$[Hmim]_5PMo_{10}V_2O_{40}$</TEX> showed a high catalytic activity in the oxidative desulfurization of sulfur-containing compounds in 1-methylimidazolium tetrafluoroborate (<TEX>$[Hmim]BF_4$</TEX>) ionic liquid using 30% aqueous <TEX>$H_2O_2$</TEX> as the oxidant. The catalytic system was of high activity, simplified workup and flexible recyclability. The catalytic oxidation reactivity of sulfur-containing compounds decreased in the order dibenzothiophene (DBT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The influences of various parameters including reaction time (t) and temperature (T), catalyst dosage, and oxidant to sulfur molar ratio n(O)/n(S) on the desulfurization of model oil were investigated in details. 99.1% of DBT conversion in the model oil was achieved at atmospheric pressure under the optimal conditions: n(O)/n(S) = 4:1, <TEX>$60^{\circ}C$</TEX>, 100 min and molar ratio of catalyst to sulfur of 0.062. The ionic liquid can be recycled six times without significant decrease in activity.

Fast oxidative desulfurization of fuel oil using dialkylpyridinium tetrachloroferrates ionic liquids

In this work, a series of Lewis acidic ionic liquids (ILs), dialkylpyridinium tetrachloroferrates [C43MPy] FeCl4,[C83MPy] FeCl4, and [C83MPy] FeCl4), was synthesized and utilized as extractant and catalyst to investigate the oxidative removal of dibenzothiophene (DBT) from model oil, with 30wt% hydrogen peroxide (H2O2) solution as oxidant. The effects of reaction time, temperature, H2O2/DBT molar ratio, initial sulfur content, IL/oil mass ratio, and alkyl chain length of IL cation ring on the DBT removal of model oil were investigated in detail. Dialkylpyridinium tetrachloroferrates ILs presented good catalytic activity and high extraction performance on the desulfurization of model oil, with the advantages of fast reaction equilibrium, high sulfur removal of 100%, low temperature, and low mass ratio of IL/oil. The desulfurization system could be recycled twice without a significant decrease in desulfurization activity. Kinetics of oxidative desulfurization of DBT by H2O2 and [C43MPy] FeCl4 is first-order with an apparent rate constant of 0.9951min−1 at 1/3 IL/oil mass ratio and 298K. [C83MPy] FeCl4 can reduce sulfur content in actual gasoline from 468ppm to 261ppm with a sulfur removal of 44% at IL/gasoline mass ratio of 1/3. The present work shows that fuel oil can be purified into ultralow sulfur fuels through further deep oxidative desulfurization using acidic ILs after hydrodesulfurization.

Deep Desulfurization of Model Oil Using Ionic Liquid and Active Carbon Binary System

Ionic liquid (IL) N-methyl-N-methylimidazoliumdimethyl phosphate ([DMIM][DMP]) and active carbon (AC) binary system were established and demonstrated to be effective for the deep removal of sulfur compounds (Dibenzothiophene, DBT) from model oil at room temperature. Mass ratio of IL to active carbon on the extractive performance, desulfurization temperature, time and desulfurization reagent to model oil were investigated. In the first stage desulfurization efficiency of binary system, IL and active carbon were 65.09%, 51.72% and 47.3%，which was followed the order of binary system &gt; IL &gt; active carbon. It was suitable to carried out desulfurization process with mass ratio of IL to active carbon in 1:1, binary system to model oil in 1:1 for 10 min at 25-45oC. In the optimiazed condition, desulfurization efficiency of binary system was nearly 100% after the fifth stage desulfurization process.

Desulfurization of Model Oil Containing Dibenzothiophene or 4,6-Dimethyl Dibenzothiophene by Alginate Immobilized Cells

Gram-negative bacterium, Pseudomonas delafieldii R-8 (CGMCC 0570) is capable of desulfurizing dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to produce corresponding monohydroxydimethylbiphenyl. The immobilization of the resting cells of this strain in Ca-alginate gel effectively improved the stability of the cells and the desulfurization ability per amount of cells. 1 mmol/L of DBT and 4,6-DMDBT could be completely degraded in about 1 d. About 39 percent of the activity for 4,6-DMDBT was recovered after immobilization. The desulfurization activity was increased with the decrease of the diameter of the beads. The Ca-alginate immobilized cells could be used repeatedly for over 190 h with the addition of calcium ions to strengthen them. A thin layer of hydrophobic polyurea was coated on the surface of Ca-alginate gel using a simple method. The desulfurization activity was enhanced after the coating.

Enhanced biodesulfurization by magnetic immobilized Rhodococcus erythropolis LSSE8-1-vgb assembled with nano-γ-Al2O3

Biodesulfurization activity can be enhanced by assembling nano-γ-Al2O3 particles on the magnetic immobilized Rhodococcus erythropolis LSSE8-1-vgb. The cells can be collected and reused conveniently by an external magnetic field. Firstly, cells were magnetic immobilized by coating with Fe3O4 nano-particles. The optimal ratio of cells to magnetic Fe3O4 nano-particles was determined to be 50:1 (g/g). Then nano-γ-Al2O3 adsorbents were assembled onto the cells to enhance the desulfurization activity. The nano-γ-Al2O3 adsorbent had the largest pore volume as well as specific surface area, and the strongest electrostatics interaction with microbial cell, and cells assembled with this nano-adsorbent performed the highest desulfurization activity. The activity of magnetic immobilized cells assembled with adsorbents was tested in desulfurization of model oil. The desulfurization rate was raised by nearly 20% when the amount ratio of magnetic particles to adsorbents was 1:5 (g/g). These cells can be reused. The activity decreased less than 10% through out three desulfurization-activation-reuse recycles.

Optimization of Oxidative Desulfurization of Dibenzothiophene Using a Coordinated Ionic Liquid as Catalytic Solvent

Oxidative desulfurization (ODS) of dibenzothiophene (DBT) in n-octane with hydrogen peroxide/acetic acid using a quaternary ammonium coordinated ionic liquid (IL) (C4H9)4NBr · 2C6H11NO as catalytic solvent has been studied. The ODS mechanism by coordinated ionic liquid [(C4H9)4NBr · 2C6H11NO] was also carried out. The sulfur-containing compounds in model oil were extracted into ionic liquid phase and oxidized to their corresponding sulfones by H2O2. The effect factors for desulfurization of model oil were investigated in detail by means of monofactorial and orthogonal experiments (L16(4)4). The results showed that the desulfurization efficiency of model oil could reach 98.6% under the optimal conditions of oxidation time, oxidation temperature, molar ratio of H2O2/sulfur (O/S), and volume ratio of model oil to coordinated ionic liquid were 30 min, 50°C, 16, and 1, respectively. The influences to the desulfurization efficiency of DBT decreased in the following order: volume ratio of model oil to coordinated ionic liquid (C4H9)4NBr · 2C6H11NO (Vmodel oil/VIL) > molar ratio of O/S > oxidation temperature > oxidation time, according to extreme analysis of the orthogonal test. The coordinated ionic liquid (C4H9)4NBr · 2C6H11NO can be recycled 5 times without a significant decrease in desulfurization.