High‐performance adsorptive desulfurization by ternary hybrid boron carbon nitride aerogel

New Adsorption Materials for Deep Desulfurization of Fuel Oil

In recent years, due to the rapid growth of mankind's demand for energy, harmful gases (SOx) produced by the combustion of sulfur-containing compounds in fuel oil have caused serious problems to the ecological environment and human health. Therefore, in order to solve this hidden danger from the source, countries around the world have created increasingly strict standards for the sulfur content in fuel. Adsorption desulfurization technology has attracted wide attention due to its advantages of energy saving and low operating cost. This paper reviewed the latest research progress on various porous adsorption materials. The future challenges and research directions of adsorption materials to meet the needs of clean fuels are proposed.

Crystal-Plane-Engineered TiO2-Anchored Vanadium Single Atoms and Clusters for Boosting Ultradeep Aerobic Oxidative Desulfurization of Diesel

The crystal plane effect has gained extensive attention in heterogeneous catalysis reactions; however, it is far from being systematically probed in titanium dioxide (TiO2)-supported vanadium catalysts. Herein, a series of vanadium (V) single atoms and clusters anchored on TiO2 with different crystal planes was fabricated by an improved "top-down" protocol. The dispersion state, electronic structure, and redox properties of the V single-atom and VOx cluster-supported catalysts were systematically analyzed by a series of characterization methods, including X-ray absorption near edge structure (XANES) and density functional theory (DFT) calculations, and their catalytic performances were examined for aerobic oxidative desulfurization (AODS) of 4,6-dimethyl-dibenzothiophen (4,6-DMDBT) with O2 as the oxidant. The results unveiled that the synergistic effect between the V single atom and the VOx cluster perceptibly promoted the catalytic performances of VOx/TiO2 samples. Therein, VOx/TiO2-(001) shows the lowest apparent activation energy (Ea) value of 46.3 kJ/mol and the optimal AODS performance with complete 4,6-DMDBT conversion to 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) within 60 min at 120 °C as compared with VOx/TiO2-(101) (81.9 kJ/mol and 180 min) and VOx/TiO2-(100) (68.0 kJ/mol and 240 min), which should be attributed to its higher V5+/V4+ ratio, the optimal redox behavior of the V species, the moderate adsorption energy between 4,6-DMDBT and VOx active centers, and the synthetic effect of V single atoms and VOx clusters. Moreover, VOx/TiO2-(001) exhibits robust durability in seven cycles of reuse, showcasing the potential for practical applications in the future.

Atomically Dispersed Aluminum Sites in Hexagonal Boron Nitride Nanofibers for Boosting Adsorptive Desulfurization Performance

The exploitation of highly efficient and cost-effective selective adsorbents for adsorptive desulfurization (ADS) remains a challenge. Fortunately, single-atom adsorbents (SAAs) characterized by maximized atom utilization and atomically dispersed adsorption sites have great potential to solve this problem as an emerging class of adsorption materials. Herein, aiming at improving the efficiency of ADS performance via the economical and feasible strategy, the desirable SAAs have been fabricated by uniformly anchoring aluminum (Al) atoms on hexagonal boron nitride nanofibers (BNNF) via an in situ pyrolysis method. Remarkably, Al-BN-1.0 exhibited a superior adsorption capacity of 46.1 mg S/g adsorbent for dibenzothiophene, with a 45% increase in adsorption capacity compared to the pristine BNNF. Additionally, it demonstrated excellent adsorption of other thiophene sulfides. Moreover, the ADS mechanisms have been investigated through special adsorption experiments combined with density functional theory (DFT) calculations. It was demonstrated that the superior ADS performance and selectivity of Al-BN-1.0 originate from the sulfur-aluminum (S-Al) and π-π interactions cooperating synergistically. This work would cast light on a novel fabrication strategy for the SAAs based on the two-dimensional material with a tunable metal site configurations and densities for varied selective adsorption and separation.

Experimental and Theoretical Density Functional Theory Approaches for Desulfurization of Dibenzothiophene from Diesel Fuel with Imidazole-Based Heteropolyacid Catalysts

Oxidative desulfurization (ODS) has been proved to be an efficient strategy for the removal of aromatic sulfur compounds from diesel oils, which are one of the main sources of air pollution. Heteropolyacid catalysts are highly active species for ODS, but the promotion of their catalytic activity and clarification of their catalytic mechanism remain an important issue. Herein, a series of novel imidazole-based heteropolyacid catalysts are prepared by a one-pot method for multiphase deep ODS of fuel with hydrogen peroxide as an oxidant. The experimental results show that the desulfurization performance of the prepared imidazole-based heteropolyacid catalysts is high up to 99.9% under mild conditions. The catalyst also possesses excellent recovery performance, and the desulfurization activity remains at 97.7% after being recycled seven times. Furthermore, density functional theory calculation is first employed to clarify the origin of the high desulfurization activity, and the results show that with the imidazole-based heteropolyacid (HPW-VIM) as the catalyst, the energy barrier is much lower than that with phosphotungstic acid (HPW) as the catalyst.

Engineering polyhedral high entropy oxide with high-index facets via mechanochemistry-assisted strategy for efficient oxidative desulfurization

High entropy oxides are promising catalysts for numerous catalytic oxidation processes with oxygen as the oxidant. However, most of them often show bulk morphologies, which hinders the full exposure of active sites. In this work, a unique 26-faceted polyhedral high entropy oxide MnNiCuZnCoOx-1000 (P-HEO) with highly active site exposure is fabricated via a mechanochemistry-assisted strategy. By employing such a strategy, the supersaturation of P-HEO during the crystal growth process is effectively reduced to form high-index facets, which is proved to be beneficial to the formation of high-index facets. Characterization results indicate that more oxygen vacancies are generated in P-HEO compared with the bulk counterparts. Density functional theory calculations reveal that the high-index facets {-211} can facilitate adsorption and activation of O2 because of the higher adsorption energy -2.23 eV compared with that of (111) surfaces (-1.79 eV), which induces significantly enhanced activity for organic sulfides oxidation. Interestingly, the synthesized P-HEO with high-index facets shows a 98.4% removal rate of dibenzothiophene from model oil within 8 h at 120 °C, which is much higher than that of the bulk counterparts (33.5%).

Synthesis, characterization and application of organoclays for adsorptive desulfurization of fuel oil

The present study encompasses the application of cost effective, organo-modified bentonite material for efficient desulfurization of model oil and real fuel. For the adsorptive desulfurization of oil, dibenzothiophene (DBT) was used as model compound. Various experimental parameters (time, temperature, adsorbent-amount and DBT concentration) were thoroughly investigated. The synthesized material was characterized via X-ray diffraction (XRD), X-ray Fluorescence (XRF), Scanning electron microscopy (SEM), Energy dispersive x-ray (EDX), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The modification exhibits the increase in interlayer spacing of clay as confirmed from XRD and modified material shows interesting morphology as compared to unmodified bentonite. The results showed that > 90% of DBT removal was achieved under optimized conditions for B-BTC, B-BTB and B-DSS and > 80% for B-BEHA, for model fuel oil which are greater than unmodified clay (< 45%). Additionally, the findings from desulfurization of real fuel oil declare that 96.76% and 95.83% removal efficiency was achieved for kerosene and diesel oil respectively, at optimized conditions and fuel properties follow ASTM specifications. The obtained findings well fitted with thermodynamic, isothermal (Langmuir) with adsorption capacity (70.8 (B-BTC), 66 (B-BTB), 61.2 (B-DSS) and 55.2 (B-BEHA) in mg/g) and pseudo-second-order kinetics. In thermodynamic studies, negative sign ([Formula: see text] specifies the spontaneity whereas, [Formula: see text] endothermic and positive sign [Formula: see text] show randomness after DBT adsorption onto organoclay.

Phosphomolybdic acid encapsulated in ZIF-8-based porous ionic liquids for reactive extraction desulfurization of fuels

Phosphomolybdic acid was encapsulated within a ZIF-8-based porous ionic liquid (HPMo@ZIF-8-PIL) for ultradeep reactive extraction desulfurization.