Dibenzothiophene Adsorption Capacity Research Articles

Solvent-free synthesis of highly dispersed zinc-doped porous carbons as efficient dibenzothiophene adsorbents

Designing efficient adsorbents for the deep removal of refractory dibenzothiophene (DBT) from fuel oil is vital for addressing environmental issues such as acid rain. Herein, zinc gluconate and urea-derived porous carbons SF-ZnNC-T (T represents the carbonization temperature) were synthesized without solvents. Through a temperature-controlled process of “melting the zinc gluconate and urea mixture, forming H-bonded polymers, and carbonizing the polymers,” the optimal carbon, SF-ZnNC-900, was obtained with a large surface area (2280 m2 g), highly dispersed Zn sites, and hierarchical pore structures. Consequently, SF-ZnNC-900 demonstrated significantly higher DBT adsorption capacity of 43.2 mg S g−1, compared to just 4.3 mg S g−1 for the precursor. It also demonstrated good reusability, a fast adsorption rate, and the ability for ultra-deep desulfurization. The superior DBT adsorption performance resulted from the evaporation of residual zinc species, which generated abundant mesopores that facilitated DBT transformation, as well as the formation of Zn-Nx sites that strengthened the host-guest interaction (ΔE = −1.466 eV). The solvent-free synthesized highly dispersed Zn-doped carbon shows great potential for producing sulfur-free fuel oil and for designing metal-loaded carbon adsorbents.

In-silico design of Metal oxide-Biochar composites for enhanced dibenzothiophene adsorption: DFT and statistical physics approach

This study proposes an efficient in-silico adsorbent material selection strategy for clean fuel combustion by leveraging Density Functional Theory (DFT) calculated reactivity parameters to optimize material configurations for enhanced dibenzothiophene (DBT) adsorption from model fuel oil (n-octane). A DFT screening identified TiO2 as the optimal material for DBT adsorption from biochar and four metal oxide (MOx) based on calculated adsorption energies (Eads). Further DFT optimization identified a 10 % TiO2 composition with biochar (TBC10) as the optimal material. This composite exhibited the strongest DBT interaction (−370.3 kcal mol−1) and a remarkably short sulfur-titanium bond (2.64 Å), indicative of an ideal adsorption geometry. Notably, TBC10 features a unique composite structure: TiO2 connected to BC via van der Waals forces, while DBT directly interacts with AC through π-π stacking and covalent sulfur-titanium bonds. To validate theoretical predictions, the designed composites were synthesized and experimentally evaluated. The excellent alignment between experimental adsorption performance and DFT-calculated adsorption energies corroborated TBC10′s superior DBT adsorption capacity. Employing a systematic optimization process, the most effective parameters for TBC10′s DBT removal from a 150 mL solution containing an initial DBT concentration of 45 mg L-1 were established as: a 30 min contact time, an adsorbent dosage of 13 mg, and a temperature of 25 °C. Under these conditions, TBC10 achieved a remarkable removal efficiency (RRDBT) of 99.82 % and a maximum DBT uptake capacity (qDBT) of 31.1 mg g−1. Kinetic and statistical physics modeling revealed a multi-molecular adsorption process with distinct binding sites, characterized by spontaneous endothermic interactions and involving both physical and chemical mechanisms. The in-silico methodology for adsorbent design reduces experimentation time, cost and identifies optimal candidates for DBT removal, enhancing fuel desulfurization and promoting sustainable combustion. This novel in-silico design paradigm holds immense potential for the development of next-generation adsorbents for various environmental remediation and industrial separation processes.

Application of aminated chitosan/functionalized carbon nanotube (CNT) nanocomposite in adsorption desulfurization of fuels containing dibenzothiophene (DBT)

The desulfurization process of fuels is a requirement due to environmental pollution. Different techniques are used in the desulfurization process such as adsorption desulfurization. In this work, aminated chitosan and functionalized carbon nanotube were used to prepare adsorbent nanocomposite and as a model sulfur-containing aromatic compound, dibenzothiophene (DBT) was employed. Fourier transform infrared spectroscopy, scanning electron microscopy and tunneling electron microscopy, and the N2 adsorption–desorption isotherm techniques were used for the characterization of the synthesized nanocomposite. The microscopic images revealed the structure of the adsorbent was mesoporous with a pore diameter of about 21 nm. The desulfurization study was conducted by batch adsorption experiments in various mass-loaded adsorbents, contact time, concentration, and temperatures for thermodynamic and kinetic behavior of adsorbents. The results showed adsorption capacity and removal efficiency of DBT were 36.4 mg/g and 64.1%, respectively. The best-fitted kinetic and isotherm models were obtained to be the pseudo-second-order model and Frendulich model, respectively. Also, by comparing the pristine nanocomposite (pristine chitosan) desulfurization results with functionalized ones, it showed a 20% enhancement in adsorption capacity by an increase in amine group numbers. According to the results of this study, this novel nanocomposite has the potential to be used in the adsorption desulfurization process.

Adsorption of Dibenzothiophene in Gasoline by Si-MCM-41/Sodium Alginate Porous Hybrid Membrane

In this paper, the novel Si-MCM-41/SA porous hybrid membrane was prepared by in-corporating inorganic mesoporous material Si-MCM-41 into sodium alginate (SA) matrix, then cross-linking with 5% glutaraldehyde and 1.0 mol/L hydrochloric acid. Using scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and atomic force microscope (AFM), the prepared Si-MCM-41 sample and Si-MCM-41/SA porous hybrid membrane were characterized. The adsorption kinetics of the dibenzothiophene (DBT) by the Si-MCM-41/SA porous hybrid membrane was explored. Meanwhile, the effects of Si-MCM-41 content, porogen addition amount, DBT concentration, solution temperature, toluene concentration and other factors on the adsorption property of the Si-MCM-41/SA porous hybrid membrane were studied. In addition, the selectivity and reusability of the Si-MCM-41/SA porous hybrid membrane were also explored. The results show that the Si-MCM-41/SA porous hybrid membrane has excellent adsorption capacity for DBT, reaching 350.74 mg/g, which is a great improvement over the pure SA membrane. Moreover, among three sulfides of thiophene, 3-methylthiophene and DBT, the Si-MCM-41/SA porous hybrid membrane has the highest adsorption selectivity for DBT. The Si-MCM-41/SA porous hybrid membrane can be reused at least 5 times. Therefore, it can be known that the Si-MCM-41/SA porous hybrid membrane is an ideal adsorption material with practical application prospects.

Synergistic effect of nitrogen and molybdenum on activated carbon matrix for selective adsorptive Desulfurization: Insights into surface chemistry modification

This study reports the synthesis of mesoporous metal-modified nitrogen doped activated carbon (AC-N-Mo) from date seeds by ZnCl 2 activation and its applicability for selective adsorptive desulfurization of dibenzothiophene (DBT). The AC-N-Mo exhibits higher adsorption capacity for DBT at 100 mg-S/L with the maximum removal percentage of 99.7 % corresponding to 19.94 mg-S/g at room temperature than the unmodified carbon with 17.96 mg-S/g despite its highest surface area and pore volume of 1027 m 2 g −1 and 0.55 cm 3 g −1 respectively. The adsorption capacity breakthrough follows the order AC-N-Mo > AC-Mo > AC > AC-N. Also, AC-N-Mo displays excellent selectivity in the presence of aromatics (toluene, naphthalene, and 1-methylisoquinoline). The enhancement in the DBT uptake capacities of AC-N-Mo is attributed to the synergistic effect of nitrogen heteroatom that aids the dispersion of molybdenum nanoparticles on carbon surface thereby improving its surface chemistry and promising textural characteristics. The kinetic studies showed that the DBT adsorption proceeds via pseudo-second order kinetics while the isotherm revealed that Langmuir fit the data more accurately for the adsorbents. The physical properties (surface area, pore volume, particle size, etc.) and chemical properties (carbon content, etc.) of as-prepared adsorbents namely; AC, AC-N, AC-N-Mo, and AC-Mo were characterized by N 2 – physisorption, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Spectroscopy/Energy Dispersive Spectroscopy (SEM/EDS), Raman Spectroscopy (RS), Fourier Transform Infrared Spectroscopy (FTIR) and Ammonia-Temperature-Programmed Desorption ( NH 3 -TPD).

Adsorptive desulphurisation of benzothiophene and dibenzothiophene from model fuels with modified vermiculite

ABSTRACT Vermiculite clay was modified with calcium oxide in order to remove Dibenzothiophene (DBT) and Benzothiophene (BT) from Model Fuels (1:1 volume mixture of decane and hexadecane). Composite was prepared with a wetness impregnation method. The physicochemical properties of these adsorbents were characterised using thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), field-scattering scanning electron microscopy (FE-SEM), transient electron microscopy (TEM), and X-ray diffraction (XRD) analysis. The vermiculite-calcium oxide (VE-Ca) composite showed the highest adsorption capacity at an initial concentration of 30 mg/L, adsorbent dose of 120 mg, and contact time of 120 min at 25°C. The highest adsorption capacity for DBT and BT was 85.37 mg.g−1 and 93.7 mg.g−1 on VE-Ca composite, respectively. The adsorption equilibrium data were fitted to pseudo-second order kinetic and Freundlich isotherm models. The results showed the presence of calcium due to complexation between Ca2+ and thiophenic aromatic rings and chemical bonding between metals and sulphur which would improve the adsorption capacity for desulphurisation.

Oxidation Adsorptive Desulfurization of Jet Fuel Using Mesoporous Sieve Loaded with TiO2

AbstractHerein we report a simple process involving catalytic adsorptive desulfurization (CADS) of model jet fuel under mild conditions with H2O2 using TiO2 loaded on MCM‐41, SBA‐15, or multi‐walled carbon nanotubes (MWCNTs) prepared by ultrasonic assisted initial wetting impregnation. The removal of dibenzothiophene (DBT) was investigated in terms of the oxygen/sulfur ratio, temperature, loading capacity, competitive components and adsorption kinetics. The adsorption capacity and adsorption strength of TiO2/MCM‐41 were higher than those of TiO2/SBA‐15, which are related to the higher SBET of MCM‐41, or the presence of numerous silanol groups. The TiO2/MWCNTs also showed excellent DBT adsorption capacities. TiO2/MCM‐41 exhibited better selectivity toward the oxidative‐adsorptive desulfurization of DBT owing to the weak influence of competitive adsorption of aromatics; this was explained by the lack of micropores in the one‐dimensional mesoporous structure. The sample with 1 % TiO2/MCM‐41 showed a high DBT adsorption capacity and rapid kinetics, and thus proved to be an inexpensive and effective desulfurization adsorbent for producing clean jet fuel.

N-CNT/ZIF-8 nano-adsorbent for adsorptive desulfurization of the liquid streams: Experimental and

With the aim of providing clean fuels through the desulfurization, the nanocomposite of Nitrogen-doped carbon nanotube/ZiF-8 (NCNT/ZIF-8) was prepared via the hydrothermal method. The nanocomposite sorbents were evaluated in the adsorption of dibenzothiophene (DBT) from the liquid phase. In this regard, the microstructure, morphology, particle size, thermal stability and physicochemical properties of nanoadsorbents were determined by using different characterization techniques. Influences of various parameters on the adsorption capacity of the nanoadsorbents were investigated; such as the adsorbent type, adsorption time, temperature and the initial DBT concentration. The as-prepared nanoadsorbents, ZiF-8 and NCNT/ZIF-8, possessed a high surface area of 1123.9 and 1207.4 m2/g, respectively. The NCNT/ZIF-8 exhibited the DBT adsorption capacity of 81.2 mg/g which is much higher than that of the pure ZIF-8 (69.1 mg/g). This excellent performance can be ascribed to the synergistic effects of both NCNT and ZiF-8, the presence of basic groups in the NCNT structure, and the high surface area and pore volume. Moreover, the DBT equilibrium adsorption was investigated by using Langmuir, Freundlich models. The Langmuir isotherm indicated a good agreement with experimental results. In addition, adsorption kinetics were studied and it was revealed that the pseudo-second-order model exhibited a favorable fitting with the experimental data. Finally, the regenerated NCNT/ZIF-8 provided a good performance even after 3 adsorption-desorption cycles and its adsorption capacity was almost unchanged.

Effect of Zinc Chloride on the Sludge Carbon-Based Adsorbent in Diesel Desulfurization

Sulfur compounds in diesel oil can be removed by adsorption technology. Based on urban sludge as the main raw materials, activated sludge carbon-based absorbent was prepared through the cothermalization of urban sludge and rice hull by adding ZnCl2 as the chemical activator. The obtained absorbent was characterized by nitrogen adsorption, elemental analysis, FT-IR characterization. The textural structure and pore distribution results showed that the amount of the micropore and the surface area played the important roles on the adsorption capacity. The elemental analysis results revealed that the percentage of C element was the key factor in the adsorption experimental. FT-IR characterization results illustrated that the oxygen-containing groups on the absorbent surface increased significantly with the addition of ZnCl2 activator, especially the amount of alcohol hydroxyl groups and quinone hydroxyl groups. ZnCl2 activated sludge carbon-based adsorbent was applied in the adsorption capacity of dibenzothiophene with model oil. As a result, the adsorption capacity was up to 19.9 mg S/g at ZnCl2 concentration of 50 wt %, which can provided a new way for harmless and resource recovery of urban sludge.

Catalyst, Emulsion Stabilizer, and Adsorbent: Three Roles In One for Synergistically Enhancing Interfacial Catalytic Oxidative Desulfurization.

A Pickering emulsion catalytic system was proposed to reduce the transfer limitation between two immiscible reactant phases for enhancing the kinetics of heterogenetic oxidative desulfurization (ODS). By loading phosphotungstic acid (HPW) nanoparticles on a novel pyridine-based porous organic polymer of P[tVPB-VP x], the amphiphilic catalysts were produced and used as the stabilizer for Pickering emulsions. Specifically, an ultrafast ODS rate was realized in the HPW/P[tVPB-VP1]-stabilized Pickering emulsion catalytic system, and just within 15 min, 100 ppm dibenzothiophene (DBT) was completely oxidized by H2O2. Because the obtained hierarchical porous HPW/P[tVPB-VP x] catalysts showed both high adsorption capacity of DBT and excellent catalytic ODS performance, the catalysts assembling at the interface of emulsions provided this fastest reaction dynamics. Playing three roles of catalyst, emulsion stabilizer, and adsorbent, the synergistic functional catalytic emulsions can be a promising approach to significantly boost the heterogeneous catalytic ODS performance.

Adsorption desulfurization performances of Zn/Co porous carbons derived from bimetal-organic frameworks

Bimetal porous carbon Zn/Co@C materials derived from bimetal (Zn, Co)-organic frameworks (bi-MOFs) were prepared by a carbonization method in this work. These carbon materials were analyzed by some characterization technologies including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), N2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Raman spectra, Zeta potential and Boehm titration. The results demonstrated that an optimal carbonization temperature was 800 °C. The material prepared under such condition (denoted as Zn/Co@C-800) had good porous structures, uniformly distributed metal active sites, high surface area (531.1 m2 g−1) and large pore volume (0.449 cm3 g−1). In addition, adsorption desulfurization performances of samples for dibenzothiophene (DBT) were systematically investigated and followed an order: Zn/Co@C-800 > Zn@C-800 > Zn/Co@C-600 > Zn/Co@C-700 > Zn/Co@C-900 > Co@C-800. Pseudo second-order kinetic and Langmuir models presented best fitting results of DBT adsorbing on Zn/Co@C-800. The Zn/Co@C-800 exhibited the remarkable adsorption capacity of DBT (40.6 mg g−1) due to positive bimetallic synergistic effects.

Excellent adsorption performance of dibenzothiophene on functionalized low-cost activated carbons with different oxidation methods

ABSTRACTLow-cost activated carbon (KAC) was functionalized by HNO3, (NH4)2S2O8 and air oxidation, respectively, to remove dibenzothiophene (DBT) from model fuel. The changes in physical and chemical properties of these activated carbons were characterized by thermal analysis, elemental analysis, nitrogen adsorption apparatus, Raman spectra, scanning electron microscope and Boehm’s titration method. HNO3 and (NH4)2S2O8 oxidation result in a significant decrease in pore structure, while air oxidation only causes slight pore reduction due to the re-activation by O2. The oxygen-containing functional groups (OFGs) increase markedly after oxidative modification, in which (NH4)2S2O8 oxidation is considered as the most efficient method with respect to the introduction of OFGs. HNO3 and (NH4)2S2O8 oxidation are more selective to generate carboxyls and lactones, whereas air oxidation creates more phenols, carbonyls and ethers. The DBT adsorption capacity follows the order: NAC (HNO3-oxidized KAC) > OAC (air-oxidized KAC) > KAC > SAC ((NH4)2S2O8-oxidized KAC), implying the introduction of OFGs is beneficial for the DBT adsorption process, especially for selectivity, but excessive OFGs have a negative effect on the removal of DBT. Thus, to achieve high DBT adsorption performance, there should be a trade-off between the micropore volume and the OFGs amount.

Heteropoly acid-loaded ionic liquid@metal-organic frameworks: Effective and reusable adsorbents for the desulfurization of a liquid model fuel

An ionic liquid (IL) and a heteropoly acid (HPA) were sequentially incorporated to highly porous metal-organic frameworks (MOFs, ZIF-8 and MIL-100(Fe)) under mild conditions. The IL was synthesized from 1-methylimidazole and 1-bromobutane inside the pore structure of the MOFs via the ship-in-bottle (SIB) technique. Then, the HPA (here, phosphotungstic acid) was incorporated to IL@MOF, where the imidazolium cations play an essential role in anchoring the PA anions to form stable MOF adsorbents bearing IL and HPA. The efficiency of the tri-component adsorbents was evaluated for the adsorptive removal of thiophenics (benzothiophene (BT) and dibenzothiophene (DBT)) from liquid fuel. The BT or DBT adsorption capacity (Q0) of the modified MOFs was 1.3–1.6 and 2.0–2.5 times to that of the pristine MOFs based on the unit weight and unit surface area of the adsorbents, respectively. The increased Q0 could be explained by the synergistic affinity of IL and HPA species toward thiophenics. Moreover, the adsorbent could be reused for up to four cycles with little loss of BT adsorption capacity, indicating the stability (no leaching) of the HPA and IL within the porous MOFs. From this study, it can be concluded that HPA can be supported on IL@MOF via chemical interactions, affording stable tri-component adsorbents that can be applied to a variety of liquid phase adsorption processes.

Continuous synthesis of mesoporous Y zeolites from normal inorganic aluminosilicates and their high adsorption capacity for dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT)

Mesoporous Y composites which exhibit both crystallized micropores and large mesopores with narrow mesopore diameter distributions and controlled pore diameters were successfully synthesized. The composite is synthesized through an elaborate design of the SiO2@cationic surfactant cetyltrimethylammonium bromide (SiO2@CTAB) micelle swelled by an appropriate amount of 1,3,5-trimenthylbenzene (TMB); it is subsequently fabricated from the condensing of the Y zeolite precursors, which contain Y zeolite seeds, on the mesoscale micelle followed by a hydrothermal crystallization process. The effect of synthesis conditions such as the amounts of CTAB, TMB and TEOS added to the synthesis system on the physicochemical properties of the obtained products was examined. The as-synthesized materials were carefully characterized by employing XRD, N2 adsorption–desorption, SEM, TEM and pyridine-adsorbed FTIR techniques. The mesoporous Y zeolite exhibited both the typical diffraction characteristics of Y zeolites in the wide-angle XRD pattern, and the typical diffraction characteristics of a narrowly dispersed mesopore structure in the small-angle XRD pattern is successfully synthesized for the first time. Finally, the adsorption capacity for DBT and 4,6-DMDBT by samples with different mesopore diameters were assessed by a batch method. Sample MY-0.5C-0.35T-0.9B showed the highest capacity for adsorbing DBT in model diesel, and sample MY-0.5C-0.35T-1.5B showed the highest capacity for adsorbing 4,6-DMDBT in model diesel. Most importantly, sample MY-0.5C-0.35T-1.5B showed the highest adsorptive rate for both DBT and 4,6-DMDBT, which is at least 10 times faster than that of sample MY-0C-0.35T-0B because of the elimination of the diffusion limitation.

A novel surface imprinted polymer/magnetic hydroxyapatite nanocomposite for selective dibenzothiophene scavenging

Highly selective adsorbent for dibenzothiophene (DBT) was successfully designed and prepared. Molecularly imprinted polymer (MIP) and magnetic hydroxyapatite (MHAP) were used as building blocks for the novel nanocomposite adsorbent. MIP/MHAP was synthesized by grafting polymerization and surface molecular imprinting using DBT as a template molecule. The microstructure and morphology of the designed nanoadsorbent were examined via FTIR, SEM and VSM. Specific surface area and pore size distribution were determined by Quantachrome Nova 3200S automated gas sorption apparatus. Additionally, static adsorption experiments, isotherms and selective recognition adsorption studies were carried out. Reversed-phase high performance liquid chromatography (RP-HPLC) was used to determine DBT. The experimental data exhibits excellent adsorption capacity for DBT reaches 247mg/g within 60min. Competitive adsorption results proved that MIP/MHAP have a greater affinity towards DBT molecules than benzothiophene analogues. Pseudo-second-order model and the Langmuir isotherm were used to describe the adsorption process.

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.

Metal‐organic frameworks for highly efficient adsorption of dibenzothiophene from liquid fuels

By taking desulfurization of liquid fuels as a demonstrative example, a bottom‐up selection was performed to find the metal‐organic frameworks (MOF)‐type adsorbents with highly efficient adsorption performance of large molecules. Through carefully analyzing the adsorption mechanism for typical S‐heterocyclic compounds like dibenzothiophene (DBT), PCN‐10 was selected in consideration of the simultaneous inclusion of several kinds of interactions in the framework. Experimental results demonstrate that this MOF exhibits extraordinary high DBT adsorption capacity (75.24 mg S g−1), showing record uptake among all the reported porous materials for the removal of thiophenicsulfur from fuels (below 1000 ppmwS), to the best of our knowledge. Moreover, the removal rate for the low sulfur concentration (50 ppmwS) can reach beyond 99%. This strategy can be conveniently extended to the screening and design of MOFs for the efficient removal of other important large guest molecules. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4491–4496, 2016

Adsorption isotherms and kinetics for dibenzothiophene on activated carbon and carbon nanotube doped with nickel oxide nanoparticles

Activated carbon (AC) and multiwall carbon nanotubes (CNT) doped with 1, 5 and 10% Ni in the form of nickel oxide nanoparticles were prepared using the wetness impregnation method. These percentages were denoted by the endings NI1, NI5 and NI10 in the notations ACNI1, ACNI5, ACNI10 and CNTNI1, CNTNI5, CNTNIL10, respectively. The physicochemical properties for these adsorbents were characterized using N 2 adsorption–desorption surface area analyzer, thermal gravimetric analysis (TGA), scanning electron microscopy, energy-dispersive X-ray spectroscopy, field-emission transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectrometre. Adsorption isotherms were obtained and desulphurization kinetics were carried out on solutions of dibenzothiophene (DBT) and thiophene in a model fuel. The efficiencies of DBT and thiophene removal were reported. The adsorption isotherms fitted the Langmuir and Freundlich models. The highest adsorption capacity for DBT was 74± 5 mg g−1 on ACNI5; the maximum adsorption capacities of the other adsorbents followed the trend ACNI1 > ACNI10 > AC > CNTNI5 > CNTNI1 > CNTNI10 > CNT. The adsorption rates for DBT and thiophene followed pseudo-second-order kinetics. The selective removal by these adsorbents of DBT relative to thiophene and naphthalene was evaluated. The adsorbents’ reusability and the effect of the percentage of aromatic compounds on their adsorption capacity were also reported.

The nature and kinetics of the adsorption of dibenzothiophene in model diesel fuel on carbonaceous materials loaded with aluminum oxide particles

The resulted environmental and industrial problems from presence of sulfur compounds such as dibenzothiophene (DBT) in some fuel led to attract greater interest in research on the removal of these compounds. In this study the adsorption isotherms of dibenzothiophene (DBT) in model diesel fuel were obtained and desulfurization kinetics was carried out. The adsorbents used were commercial coconut activated carbon (AC), multiwall carbon nanotubes (CNT) and synthesized graphene oxide (GO) loaded with 5% and 10.9% aluminum (Al) in the form of aluminum oxide (Al2O3) particles to improve the chemical properties of their surface. The physicochemical properties for these adsorbents were characterized using thermal gravimetric analysis (TGA), N2 adsorption–desorption surface area analyzer, scanning electron microscope (SEM), energetic dispersive X-ray diffractogram (EDX), field emission electron microscope (FE-TEM) and X-ray photoelectron spectrometer (XPS). The adsorption capacities for DBT on the aluminum oxide modified adsorbents are improved by about twofold, which is attributable to introduction of Al2O3 Lewis acid as an additional adsorption site. The highest adsorption capacity for DBT (85±1mg/g) with high selectivity factor relative to naphthalene (54mg/g) was achieved using loaded activated carbon with 5% Al. The adsorption capacities, removal selectivity and efficiencies with which the other prepared adsorbents remove DBT from model fuel are reported. The adsorption isotherms fitted both the Langmuir and Freundlich models. The adsorption rate for DBT follows pseudo-second order kinetics with correlation coefficients close to 1.00. The adsorbents are stable and reusable for at least 5 times.

Screening of desulfurization adsorbent in metal–organic frameworks: A classical density functional approach

High-throughput screening of desulfurization adsorbent has been implemented by introducing a classical density functional theory (CDFT). The screening is focused on the adsorption capacity of dibenzothiophene (DBT) in 458 types of metal–organic frameworks (MOFs). Comparing to the state of art desulfurization adsorbent, the best MOF for low concentration (BMLC) shows an uptake 27 times of HKUST-1 while the best MOF for high concentration (BMHC) shows an uptake twice of HKUST-1. Hierarchical porous structure has been found in BMLC and BMHC, respectively. According to the radial distribution function, a layered adsorption mechanism has been found in BMLC instead of BMHC; and the thermodynamic differences between BMLC and BMHC can be understood by this lamellar adsorption mechanism.