Dibenzothiophene Research Articles (Page 1)

In this study, we present a comprehensive characterization of a highly efficient desulfurizing bacterial isolate, SB1D. The isolate exhibited remarkable desulfurization of dibenzothiophene (DBT) and demonstrated the ability to metabolize benzothiophene (BT) and several of their alkylated derivatives. Genome-related index analyses, including 16S rRNA gene similarity (100%), Average Nucleotide Identity (ANI; 98.7%), digital DNA-DNA hybridization (dDDH; 88.7%), and phylogenomics, identified the strain as Rhodococcus qingshengii. Additionally, orthologous gene cluster analysis showed that SB1D shared the highest number of ortholog clusters (60) with R. qingshengii. The GC-MS analysis of the extracted metabolites identified 2-hydroxybiphenyl (2-HBP) and 4-methylhydroxybiphenyl (4-MHBP) as the major end-products of DBT and 4-methyldibenzothiophene (4-MDBT) desulfurization, respectively. The RAST genomic analysis revealed the presence of several organic-sulfur metabolism-related genes in the genome of SB1D. Together, these findings confirm that the isolate employs the sulfur-specific 4S pathway for the desulfurization of DBT and 4-MDBT. To our knowledge, this is the first report providing genome-based characterization and desulfurization pathway analysis of R. qingshengii SB1D, with the proven ability to desulfurize multiple thiophenic compounds found in diesel, and holds promise as a valuable biocatalyst for applications in biodesulfurization.

The adsorption capacity of pyrolyzed rice husks was investigated with respect to individual model solutions of benzothiophene (BT) and dibenzothiophene (DBT), and a model mixture containing benzothiophene, dibenzothiophene and 4,6,-dimethyldibenzothiophene (4,6 –DMDBT). The adsorption process was carried out under dynamic conditions. The influence of temperature and initial concentration of sulfur compounds in individual model fuels was investigated. The highest adsorption capacity was achieved at 60°C and the highest initial sulfur concentration in the model fuels. Carrying out the adsorption at higher temperatures leads to an increase in the degree of desulfurization, which means that the adsorption process is not only physical in nature. The adsorption selectivity of the pyrolyzed rice husk from mixture model fuel decreases in the order DBT > 4, 6–DMDBT > BT.

Sulfur-containing organic compounds present in transportation fuels such as gasoline and diesel are a major source of environmental pollution, primarily due to the emission of sulfur oxides (SOₓ) during combustion. In response, increasingly stringent global regulations have been implemented to limit sulfur content in fuels. In this study, a nanocomposite photocatalyst composed of indium sulfide (In₂S₃) and halloysite was synthesized via a two-step hydrothermal process. The structural, morphological, and optical properties of the resulting photocatalysts were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV – Vis diffuse reflectance spectroscopy (UV – Vis DRS). The photocatalytic performance of the In₂S₃/Halloysite composite was evaluated through the oxidative desulfurization of dibenzothiophene (DBT) under visible light irradiation. Under optimized conditions — reaction temperature of 70 °C, 1.0 mL H₂O₂ as the oxidant, and 40 mg of photocatalyst — the DBT conversion reached 96% after 5 hours. These results highlight the potential application of In₂S₃/Halloysite nanocomposites as efficient visible-light-responsive photocatalysts for sulfur removal from fuels.

Adsorption desulfurization of fuel oil is regarded as one of the most promising technologies for obtaining clean fuel because it can remove refractory sulfur compounds at ambient temperature and pressure. Studies indicate that HKUST-1, as an important type of metal–organic framework (MOF), is a potential candidate for adsorption desulfurization of fuel oil. In this work, we report that defective HKUST-1 can be rapidly synthesized at room temperature with the aid of NH4F and exhibit superior adsorption desulfurization performance compared to conventional HKUST-1 by the solvothermal method. Moreover, the influence of adsorption parameters on the desulfurization performance of HKUST-1 prepared with the aid of NH4F was investigated. We used 50 mg of HKUST-1-5 synthesized with 5 wt% added NH4F to adsorb 5 g of model oil with a sulfur concentration of 1000 ppm at 25 °C for 1 h, and the adsorption capacity of the adsorbent reached 23.8 mgS/g, 46.8 mgS/g and 36.8 mgS/g for benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT), respectively, which are higher values than those of conventional HKUST-1. Such performance can be mainly attributed to its relatively small particle size and the presence of more unsaturated Cu sites. The results of regeneration experiments show that HKUST-1-5 still maintains excellent adsorption performance after four cycles. These findings highlight the great potential of this material as an efficient adsorbent for adsorption desulfurization of fuel oil.

Exogenous DBT and overexpression of deoR improved the waste tire rubber desulfurization ability of a newly isolated Escherichia sp. strain.

Abstract This study synthesized and characterized a new composite of activated carbon-zinc oxide/aluminum oxide (AC–ZnO/Al2O3) to assess its capability to simultaneously extract sulfur compounds from crude oil and other chemical pollutants from sewage water. The composite was made by wet impregnation with subsequent heating at 450 °C which resulted in even distribution of the metal oxide nanoparticles with diameters of ZnO 18.3 nm and Al2O3 15.7 nm on the carbon matrix. Surface properties showed improvement with BET surface area increasing from 1110 m2/g to 1247 m2/g and total pore volume expanding to 0.68 cm3/g. Greater adsorption performance was exhibited for dibenzothiophene (DBT) removal with a maximum capacity of 58.7 mg/g which is a 66.8 % improvement over pristine activated carbon. From synthetic sewage, pollutant removal efficiencies of 95.2 % for Pb2+, 87.4 % for phenol, and 92.8 % for methylene blue were obtained. Kinetics suggest a pseudo second-order rate and chemisorption limited in rate, Langmuir isotherm was the best fit for equilibrium data. Some spontaneous and exothermic thermodynamic processes described the adsorption. In practical applications, 85.0 % sulfur removal from crude oil and marked improvements in municipal sewage quality parameters were observed. The composite also retained 85 % of DBT removal capacity and 82 % of Pb2+ removal efficiency after five thermal regeneration cycles. The synergistic combined effects of physical adsorption on the surfaces of carbon and the chemical interactions with metal oxide sites showcased that the material could be used for industrial contaminations enabling multi-functional capabilities to simultaneously treat aqueous waste streams along with petroleum.

In this study, oxidative desulfurization of dibenzothiophene (DBT) with H2O2 as an oxidant was studied, whereas the catalyst used was zirconium oxide supported on Activated carbon (AC). Zirconium oxide (ZrO2) was impregnated over prepared activated carbon (AC) and characterized by various techniques such as XRD, FTIR, BET, SEM, and EDX. This composite was used as a heterogeneous catalyst for oxidation desulfurization of simulated oil. The results of this study showed that ZrO2/AC composite exhibited significant catalytic activity and stability, effectively lowering sulfur content under mild conditions. Factors such as reaction temperature (30, 40, 50, 60°C), time (5, 10, 15,20,30,60, 80 100 min), catalyst dose (0.3, 0.5, 0.7, 0.9 g) and initial concentration of dibenzothiophene (DBT) (20,40, 60, 80, 100, 200, 300 ppm) was used to achieved maximum efficiency. 10 ml of H2O2 /100 ml of simulated oil was used as an oxidizing agent. It was found that an increase in all the above variables led to an increase in desulfurization efficiency, except for an increase in initial DBT concentration, which led to a decrease in removal efficiency. The maximum removal efficiency of sulfur content was 92.22%, which was achieved at 60 °C and 0.9g of composite /100 ml of simulated oil at equilibrium time 100 min and 100ppm initial concentration of DBT. Finally, the reaction kinetics matched the pseudo-second order rate model, with an activation energy of 36.665 KJ/mol.

In recent years, significant efforts have been devotedto the reductionof sulfur levels in transportation fuels in order to reach regulatorylimits and reduce the emission of harmful SOx into the atmosphere. In particular, adsorptive desulfurization(ADS) has the potential to produce zero-sulfur fuels without the needfor a high energy intensity process, high H2 pressure,and long process times as in the case of other technologies such ashydrodesulfurization. In this work, we have demonstrated the effectivenessof renewable activated carbons derived from food waste (FWAC) forthe ADS of model jet and diesel fuels. The optimal FWAC materialswere those fabricated to maximize the micropore volume, providingavailable sites for the adsorption of dibenzothiophene (DBT) and dimethyldibenzothiophene(DMDBT). The FWAC had a greater sulfur adsorption capacity than commercialAC, Y zeolite sorbents, and AC derived from other biomass sourcesincluding miscanthus, coconut shell, and walnut shell. Elemental analysissuggests that the inorganic impurities inherent in food waste, notablyK, Ca, P, and Na, may contribute to its improved sulfur adsorptioncompared to other AC materials. Microscopy and X-ray diffraction studiesfurther demonstrated the presence of inorganic species on FWAC thatmay provide active sites for the chemisorption of sulfur molecules.

ABSTRACTThis study reports the efficacy of a rationally designed Pseudomonas putida strain to bring about the specific removal of S atoms from dibenzothiophene (DBT), the model heterocyclic sulfur‐containing component of raw petroleum. The emphasis on DBT as a model compound stems from its prevalence in fossil fuels and its resistance to hydrodesulfurization, which positions it as a critical target for improving biodesulfurization technologies. To this end, we explored the combinatorial space of the dsz operon of the naturally occurring strain Rhodococcus qingshengii IGTS8—known to achieve dibenzothiophene degradation—by re‐engineering the native regulation of the operon, generating permutations of the order of the cognate genes and their ribosomal‐binding sites, testing the effects of multicopy versus monocopy doses and introducing the resulting constructs in the tailor‐made host. The combination that emerged as best in terms of catalytic efficacy, moderate physiological burden, and durability was one in which the original dsz operon was refactored by [i] reordering its native gene order to dszBCA, [ii] decompressing their naturally occurring translational coupling with optimised ribosomal‐binding sites, [iii] engineering its constitutive expression with a heterologous promoter and [iv] inserting the thereby refactored pathway in the Tn7 site of the genome‐edited strain P. putida EM384, which is optimised for greater stability and hosting harsh redox reactions. The resulting P. putida DS006 exhibited exceptional DBT desulfurization activity as well as efficiency in model biphasic biodesulfurization systems.

Fishing out microorganisms for bioremediation using metagenomics: Isolation and whole-genome sequencing of the metabolically versatile Rhodococcus erythropolis LP27217 strain from oil spill lake.

Biomacromolecular engineering of redox-active chitosan-polypyrrole-clay hybrid materials for machine learning-assisted desulfurization and supercapacitor application.

The expansion of the Alberta Oil Sands Region (AOSR) has increased the deposition of petroleum-derived chemicals into the surrounding environment. Among these, polycyclic aromatic compounds (PACs), including sulfur-containing heterocyclic hydrocarbons, have been detected in exposed local wildlife, yet the reproductive toxicity and genotoxicity of this suite of PACs remain largely unexplored. This study examined the effects of dibenzothiophene (DBT) and its alkylated congener, 2,4,7-trimethyldibenzothiophene (2,4,7-DBT), on estradiol (E2) synthesis and metabolism in granulosa cells (SIGCs). Cells were exposed to DBT or 2,4,7-DBT for 24 h at concentrations detected in AOSR wildlife tissues (0, 0.1, 1 and 10 nM). We measured the gene expression of markers involved in E2 synthesis, signaling and metabolism, E2 output via ELISA and E2 metabolite production via HPLC-MS/MS. Exposure to 2,4,7-DBT, but not DBT, shifted E2 metabolism towards 4-OHE2, a genotoxic E2 metabolite. DNA damage was assessed by γH2Ax expression, alongside DNA repair (Parp1) and survival markers (pAKT). Interestingly, both DBT and 2,4,7-DBT increased DNA damage and triggered apoptosis via a caspase-independent mechanism. Given the critical role of granulosa cells in steroidogenesis and fertility, these findings highlight the endocrine-disruptive effects of sulfur-containing heterocyclic PACs and their potential to compromise reproductive health in exposed mammals.

The batch, repeated batch and fed-batch cultivation strategies, in stirred tank bioreactors, were evaluated to maximize biomass production and the cells’ desulfurization activity (CDA) of Rhodococcus qingshengii IGTS8. The batch culture reached 2.62 g DCW/L biomass, with a productivity of 0.03 g DCW·L−1·h−1 and only 26% glycerol consumption. The repeated batch strategy reduced cultivation time during the first cycle, increasing biomass production by 15%, with 30% glycerol consumed and productivity 2.3 times higher than the batch process; however, subsequent cycles showed no further improvement. CDA peaked early in both modes but declined to 12–13 U/mg DCW by the end of the exponential growth phase. Fed-batch cultivation achieved 8.35 g DCW/L with 87% glycerol consumption, resulting in a threefold increase in volumetric productivity and a 1.7-fold higher specific growth rate compared with the batch mode. CDA remained stable during the fed-batch process and was approximately 40% higher compared with the batch and repeated batch processes. The fed-batch culture was used directly in a two-phase bubble column bioreactor for the desulfurization of dibenzothiophene (DBT), 4-methyl-dibenzothiophene (4-MDBT) and their mixture. The complete desulfurization of 1.4 mM DBT was achieved at a rate of 21.6 mmol DBT/kg DCW/h, while 0.9 mM 4-MDBT was fully converted but at a 2.5-fold lower rate. The simultaneous conversion of the DBT/4-MDBT mixture showed reduced efficiencies of 59.6% and 41.2%, respectively.

The present study is conducted to investigate the adsorption desulfurization process for eliminating sulfur from a simulated fuel within a sulfur content range similar to what exists in typical naphtha streams. The model oil, n-hexane, was sulfurized with dibenzothiophene (DBT), which is the most complex form of sulfur constituents in fuels. Corncob, a natural biomass waste material, was utilized to accomplish the adsorption remedy of sulfur. The carbonization process took place at 500 °C. FTIR, SEM, XRD, AFM, and BET-surface area facilitated a comprehensive characterization of carbonized corncob (CC) adsorbent. The results showed that the corncob sample has homogeneous surfaces and relatively analogous active positions. The CC adsorbent was utilized to adsorb sulfur in its DBT configuration from the sulfurized fuel (n-hexane). Certain adsorption factors of temperature, contacting time, and adsorbent dosage were examined to select the most appropriate adsorption conditions. After that, the chosen conditions were employed to adsorb various sulfur concentrations. For the same initial concentration of sulfur of 400 ppm, the removal attained 75% at favorable parameters of 60°C, 30 min, and 3g L-1, respectively. The efficiency of sulfur removal was substantially augmented with the reduction of the initial sulfur content. Thus, it attained more than 79 % when the original concentration of sulfur in the n-hexane was maintained in the range of 100 ppm. The results perfectly coincided with the Langmuir model of adsorption isotherms. The thermodynamics of the desulfurization adsorption process reflected that the adsorption is associated with an endothermic event. The estimated standard enthalpy changes were 6.34 kJ mol-1. The adsorption was spontaneous over the employed temperature range of 30 – 60°C.

This study introduces a novel, non-extractive Oxidative Desulphurisation (ODS) method for kerosene using a three-phase Oscillatory Baffled Reactor (OBR). The process utilises commercial bentonite clay (aluminium silicate hydrate) loaded with 15 wt% vanadium pentoxide (V₂O₅) as a cost-effective catalyst. Catalyst characterisation showed surface areas of 56 m²/g for bentonite and 50.13 m²/g for the V₂O₅/bentonite composite. Structural and thermal properties were analysed using X-ray diffraction (XRD). The ODS process was tested under various conditions, including temperatures (40–80°C), residence times (15-120 min), oscillation intensities (63.79–382.8 Reo), and sulphur concentrations (84.4–578 ppm). The optimal result, 81.73% sulphur removal, was achieved at 50°C, 578 ppm sulphur, and Reo = 382.8. Kinetic analysis revealed a second-order reaction with a low activation energy of 46.39 kJ/mol for dibenzothiophene (DBT) oxidation. Unlike previous studies that relied on synthetic or metal-heavy catalysts, this research highlights the effectiveness of a natural, low-cost bentonite-based catalyst. It offers a sustainable pathway for cleaner fuel production and contributes valuable insights into reaction mechanisms and kinetics, supporting future scale-up of eco-friendly desulphurisation technologies.

To address the challenge of ultra-deep desulfurization in fuels, a series of heteropolyacid-based poly(ionic liquid) catalysts (C4-PIL@PW, C8-PIL@PW, and C16-PIL@PW) were synthesized via radical polymerization and anion exchange methods. The prepared catalysts were characterized via FT-IR, XRD pattern, and Raman spectroscopy. Optimal reaction parameters (e.g., temperature, catalyst dosage, and O/S molar ratio) were systematically investigated, as well as the catalytic mechanism. The typical sample C8-PIL@PW exhibited exceptional oxidative desulfurization (ODS) performance, achieving a sulfur removal of 99.2% for dibenzothiophene (DBT) without any organic solvent as extractant. Remarkably, the sulfur removal could still retain 89% after recycling five times without regeneration. This study provides a sustainable and high-efficiency catalyst for ODS, offering insights into fuel purification strategies.

Abstract CoMo catalysts supported on Al2O3‐MgO modified with alkaline metal oxides were synthesized, characterized, and catalytically evaluated in the hydrodesulfurization (HDS) reaction using dibenzothiophene (DBT) as a model molecule. Results showed that DBT conversion after 8 h of reaction time slightly decreases with the incorporation of Li2O, K2O, Na2O, and CaO to the Al2O3‐MgO support. However, this diminution in the catalytic activity is compensated, in the CoMo/Al2O3‐MgO‐Na2O formulation, with the increase in selectivity to biphenyl product by more than 4 times. The obtained results can be explained in terms of the support and catalyst characteristics. The increase in selectivity was related to the number of basic sites and their medium strength. The basicity of the support affects the morphology, the stacking number, and the slab length of the active phase. Non‐well‐dispersed crystals of the active phase, MoS2 and CoMoS with staking of 3 or 4 slabs and ~ 4 nm length, promote selectivity toward the direct desulfurization route, producing a higher fraction of BP through the DDS route.

The effective and deep removal of unreactive sulfides to achieve ultra-low-sulfur or sulfur-free oils has recently attracted extensive attention. In this work, a series of UiO-66 based catalysts have been prepared facilely for the effective removal of unreactive sulfides. Here, the incorporation of nitro functional groups into UiO-66, along with the construction of defects, results in remarkable sulfur removal for dibenzothiophene (DBT), achieving oil with sulfur content of less than 1 ppm. The successful construction of the designed catalysts was verified through a series of characterization studies. The exposed unsaturated metal sites help provide significantly more active reaction sites. In addition, the incorporated nitro group, with its electron-withdrawing property, would help increase the Lewis acidity of the catalytic metal sites. Thus, the catalytic oxidative capability of the designed UiO-66-based catalysts would be significantly increased. The enhanced catalytic oxidative performance helps ensure acceptable sulfur removal for oils with much higher sulfur concentrations. Additionally, the catalyst developed in this work can also be used to remove the derivatives of DBT with even lower reactivity. The relatively mild reaction conditions, combined with the exceptional sulfur removal, demonstrate the practicality of this reaction system.

The efficient removal of refractory sulfides from fuels to achieve clean oil is a primary research focus in the petrochemical industry. This study introduces extraction and catalytic oxidation desulfurization (ECODS) as a technique for effective desulfurization. A cross-linking strategy was employed to construct structurally stable isotropic microreactors based on ionic liquid (IL)-modified liposomes (poly[MimA11, A11][heteropolyanions]), where exposed imidazolium cations anchor catalytic heteropolyanions (e.g., [PW12O40]3-) to ensure active site accessibility. In this interfacial catalytic reaction, the microreactor resembles an emulsified droplet with a spherical surface, significantly enhancing the catalytic interface. Additionally, the isotropic imidazolium cations of spherical vesicles provide the equivalent driving force for the attachment of heteropolyanions (such as [PW12O40]3- and [PMo12O40]3-), ensuring full exposure of active sites and reducing mass transfer resistance. The optimized poly[MimA11, A11][PW12O40] catalyst achieved complete dibenzothiophene (DBT) removal within 1.5 h and retained 92.4% efficiency after six cycles, demonstrating exceptional activity and recyclability. The morphology, structure, and properties of the microreactors were characterized, and optimal reaction conditions were established. Building on this foundation, the removal performances across various systems and sulfur-containing targets were assessed, thereby confirming the structure-activity relationship of this type of microreactor. Furthermore, the desulfurization mechanism was inferred from the identified oxidation products. Overall, this isotropic poly[MimA11, A11][heteropolyanion] demonstrates excellent desulfurization performance and holds significant potential for broad applications.

Achieving efficient orange-red emission in thermally activated delayed fluorescence (TADF) emitters remains challenging due to the hard to achieve great balance between a small singlet-triplet energy gap and high radiative decay rates. In this study, a modification site engineering strategy for secondary donors to optimize excited-state properties for orange-red emitters is proposed. Two isomeric emitters, ND28DBT and ND37DBT, were synthesized by introducing dibenzothiophene (DBT) units at different positions of a naphthalimide-dimethylacridine (NAI-DMAc) core. The theoretical analysis indicates that ND37DBT possesses a more favorable excited-state configuration, which facilitates an efficient reverse intersystem crossing (RISC) process and accelerates the radiative decay rate. As a result, ND37DBT showed a high photoluminescence quantum yield (PLQY) (70%), a fast RISC rate (6.25×105 s-1), and an excellent external quantum efficiency (EQE) (22.1%) with minimal roll-off in 100 cd m-2. This work demonstrates that precise control of secondary donor modification sites offers a powerful molecular design strategy for developing high-efficiency orange-red TADF materials.