Search Results (38)

Effective thoracic surgery requires timely, predictable operative lung collapse. During one-lung ventilation (OLV), lung collapse is not merely a mechanical consequence of nonventilated lumen opening but a phase-dependent physiological process. Rapid phase I collapse is driven by elastic recoil and passive gas venting, whereas slower phase II collapse depends on residual alveolar gas absorption. Communication between the operative-side airway and the atmosphere before pleural opening may permit tidal gas movement, ambient air entrainment, and nitrogen re-entry during the closed-chest period, delaying subsequent absorption collapse. This narrative review reorganizes lung collapse strategies, including denitrogenation, operative-side airway occlusion, preemptive OLV, disconnection, bronchial suction, and the open-clamp airway technique, according to timing and physiological target. Before pleural opening, alveolar nitrogen should be reduced and ambient air entrainment prevented. Around the pleural opening, airway patency and brief suspension of positive-pressure ventilation may preserve elastic recoil venting. During OLV maintenance, re-clamping or limiting atmospheric communication may support residual gas absorption. This phase-based framework interprets recent clinical findings as interventions acting before, during, and after pleural opening. This may help clinicians select strategies according to the lung isolation device, oxygenation reserve, and surgical environment, although standardized endpoints and component-level validation remain necessary. Full article

This study demonstrates the high efficiency and selectivity of p-toluenesulfonic acid-based deep eutectic solvents (DESs) for simultaneous extractive denitrogenation (EDN) and desulfurization (EDS) of model fuel. Three DESs—TBPB:PTSA, TBAB:PTSA, and ChCl:PTSA (1:1 molar ratio)—were synthesized and evaluated for their effectiveness against representative heteroaromatic pollutants: thiophene, dibenzothiophene, pyridine, and carbazole. The phosphonium-based TBPB:PTSA exhibited the highest extraction performance, achieving over 96% removal of nitrogen species and up to 85% removal of sulfur species at 40 °C. Increasing the temperature enhanced desulfurization by reducing viscosity, thereby improving mass transfer kinetics. Additionally, a 3:1 ratio of DES to fuel provided an optimal balance between solvent economy and operational efficiency. Denitrogenation was driven by strong acid–base protonation facilitated by PTSA, while desulfurization was governed by π–π and dispersion interactions, modulated by the hydrophobicity of the cations. The DES achieved nearly quantitative nitrogen removal and satisfactory sulfur extraction after three reuse cycles, while multistage operation enabled complete purification within four extraction steps. ¹H NMR analysis confirmed that no DES components were found in the raffinate phase, verifying the immiscibility and stability of the solvent. These results indicate that TBPB:PTSA is a robust, regenerable, and environmentally benign solvent, effectively enabling simultaneous EDN–EDS of hydrocarbon fuels and positioning it as a promising green alternative to traditional hydrogen-based refining methods. Full article

The transition to sustainable energy systems has intensified the search for renewable alternatives to reduce greenhouse gas emissions and reliance on fossil fuels. In this context, microalgae have emerged as a promising third-generation feedstock for biofuel production due to their rapid development, high lipid content, and ability to grow in wastewater without competing with freshwater resources. In this study, the hydrotreatment of biocrudes derived from C. vulgaris, T. obliquus, and a mixed microalgal culture cultivated in domestic wastewater is investigated. Catalytic upgrading was applied using sulphided CoMo/Al₂O₃ (sCoMo) and Pt/Al₂O₃ catalysts. The results demonstrated that catalytic upgrading enhanced the upgraded bio-oils’ quality compared to non-catalysed reactions, confirming the crucial role of catalysts in improving bio-oil properties. Compared with the Pt catalyst, sCoMo produced higher yields of upgraded bio-oil, greater enrichment in carbon and hydrogen, and higher heating value (HHV), while effectively enhancing nitrogen and oxygen removal. However, when compared with the non-sulphided CoMo, the sulphiding treatment did not significantly improve denitrogenation and treated oil yields. The highest fraction of components within the jet fuel boiling range (37.7%) was obtained using a Pt catalyst, while the non-catalysed process yielded the lowest (26.6%). In this sense, catalytic upgrading of microalgae-based biocrude represents an important step towards the production of advanced and environmentally sustainable fuels. Full article

The elimination of nitrogen and sulfur compounds from liquid fuel is a critical aspect of reducing environmental pollution. However, the widely utilized hydrodesulfurization and hydrodenitrogenation technologies require harsh operating conditions. Moreover, when operated simultaneously, these processes induce mutual competition and inhibition between the two reactions, thereby limiting the actual removal efficiency. Conversely, non-hydrogenation technologies offer substantial advantages in terms of operating conditions and provide high levels of desulfurization and denitrogenation. Nevertheless, the presence of nitrogen-containing compounds has also been demonstrated to engender competition and inhibition. It is imperative to develop environmentally friendly technologies that can simultaneously desulfurize and denitrogenate. This paper reviews research progress in this field over the past decade, providing a detailed assessment and comparison of hydrogenation and non-hydrogenation technologies, including adsorption, extraction, oxidation and biological methods. Furthermore, it considers future research directions. The article’s aim is to furnish a novel perspective on the development of clean fuel sources and to investigate more economical, sustainable, and commercially viable desulfurization and denitrogenation methods. Full article

The selective removal of trace heteroatomic contaminants from fuel remains a critical challenge for clean combustion and refinery upgrading, particularly due to the chemical stability and structural similarity of sulfur- and nitrogen-containing aromatics. Herein, a surface-engineered graphene oxide aerogel functionalized with cyclodextrin (β-CD-CONH-GO) is developed via covalent grafting to introduce well-defined host–guest recognition sites within a porous framework. Spectroscopic and microscopic characterizations confirm successful functionalization, preserved aerogel morphology, and accessible hybrid interfaces. The removal process for monocyclic, bicyclic, and tricyclic impurities is governed by synergistic molecular inclusion within the cyclodextrin cavity, interfacial hydrogen bonding, and secondary confinement provided by the aerogel porosity. Thus, the β-CD-CONH-GO exhibits efficient adsorption toward representative bicyclic impurities, and the removal performance follows the order of indole > quinoline > benzothiophene. Kinetic analysis demonstrates pseudo-second-order adsorption behavior, indicating chemisorption dominated by cooperative host–guest recognition and hydrogen bonding. It possesses removal selectivity even in mixed systems containing structurally similar aliphatic and aromatic competitors and maintains > 95% efficiency after five regeneration cycles via ethanol extraction, confirming superb durability. This study demonstrates a feasible pathway to design adsorbents for deep fuel refining and highlights cyclodextrin-based graphene hybrid aerogels as promising candidates for separations. Full article

Nickel phosphide catalysts (Ni₂P) were prepared using mesoporous molecular sieves as supports during isobaric co-impregnation. Ni₂P catalysts with different loading values were characterized, showing that the active phase on the surface of the catalysts was mainly Ni₂P and the catalysts still retained the mesoporous structural characteristics of the supports. The catalysts were evaluated using a 10 mL fixed-bed hydrogenation unit. The results showed that the nickel phosphide catalysts had a higher hydrogenation capacity than the sulfide catalysts and were able to preferentially hydrogenate and saturate most of the quinolines to decahydroquinolines, reduce the conversion of 1,2,3,4-tetrahydroquinoline to o-propylaniline, and reduce the inhibition of reactivity due to competitive adsorption. The effect of the catalyst on the path selectivity of quinoline hydrogenation was investigated, and the products of quinoline hydrogenation and denitrogenation consisted mainly of propylbenzene and propylcyclohexane, with propylcyclohexane accounting for 91.7% of the product and propylbenzene for 4.8%, under the conditions of nickel phosphide catalysts. Furthermore, the 25 wt% Ni₂P/SBA-15 catalyst exhibited no significant loss of catalytic activity during a 72 h stability evaluation conducted at 360 °C. Full article

Vacuum degassing (VD) is a critical refining step in electric arc furnace (EAF) steelmaking for producing clean steel with reduced nitrogen and hydrogen content. This study develops an Effective Equilibrium Reaction Zone (EERZ) model focused on denitrogenation (de-N) by simulating interfacial reactions at the bubble–steel interface (Z1). The model incorporates key process parameters such as argon flow rate, vacuum pressure, and initial nitrogen and sulfur concentrations. A robust empirical correlation was established between de-N efficiency and the mass of Z1, reducing prediction time from a day to under a minute. Additionally, the model was further improved by incorporating a dynamic surface exposure zone (Z_eye) to account for transient ladle eye effects on nitrogen removal under deep vacuum (<10 torr), validated using synchronized plant trials and Python-based video analysis. The integrated approach—combining thermodynamic-kinetic modeling, plant validation, and image-based diagnostics—provides a robust framework for optimizing VD control and enhancing nitrogen removal control in EAF-based steelmaking. Full article

An efficient Ni-catalyzed, Mn-mediated denitrogenative cross-electrophile coupling of N-alkyl-1,2,3-benzotriazinones with alkyl tosylates and mesylates for access to o-alkyl secondary benzamides is reported. The method uses inexpensive non-anhydrous dimethyl acetamide (DMA) in combination with tetrabutyl ammonium iodide (TBAI) as a co-catalyst to convert sulfonates into iodides in situ. Scope and limitations of the protocol have been demonstrated by >30 examples with yields up to 91%, showing a large electronic effect from the N-substituent in benzotriazinones. An unexpected steric acceleration has been observed from the core of benzotriazinones, not only promising a highly efficient access to 2-alkyl-2,3-disubstituted benzamides but also shedding light on the rate-limiting steps in the catalytic cycle. Full article

In this study, catalytically active coatings on titanium were synthesized by plasma electrolytic oxidation (PEO) in aqueous electrolytes based on sodium tungstate with the addition of sodium phosphate or sodium borate and chelate complexes of iron, cobalt or nickel. Taking into account the EDX, XPS and XRD data, the oxide–phosphate coatings (PWFe, PWCo, PWNi) contained crystalline titanium oxide and amorphous tungstates and/or phosphates of iron triad metals. Amorphization was facilitated by high phosphorus concentrations (up to 6 at.%). Replacing phosphate with borate in the electrolyte with Ni(II)-EDTA complexes led to the crystallization of WO₃ and NiWO₄ in the PEO coatings (BWNi). All formed PEO coatings were active in reactions of the oxidative desulfurization (ODS) of thiophene and dibenzothiophene and oxidative denitrogenation (ODN) of pyridine, as well as in the simultaneous removal of S- and N-containing substrates from their mixture. The stability of samples with MWO₄ increased in the following series: PWNi < PWCo < PW < PWFe < BWNi. Replacing phosphate with borate in the electrolyte resulted in the preparation of catalysts with enhanced stability and activity. In contrast to PWM catalysts, the BWNi catalyst had selectivity toward the oxidation of pyridine in its mixture with thiophene. Full article

An efficient access to novel 2-substituted 1H-imidazole derivatives was developed based on acid-mediated denitrogenative transformation of 5-amino-1,2,3-triazole derivatives available through dipolar azide−nitrile cycloaddition (DCR). The proposed approach includes intramolecular cyclization of 5-amino-4-aryl-1-(2,2-diethoxyethyl) 1,2,3-triazoles followed by triazole ring opening and insertion of in situ formed carbene intermediate into the O-H bond of different alcohols under acidic conditions. Full article

An efficient and air-tolerant Ni-catalyzed denitrogenative cross-electrophile coupling of benzotriazinones with benzyl chlorides has been developed via liquid-assisted grinding by using Mn powders as reductant and DMF as assisting liquid in the presence of anhydrous calcium chloride. Scope and limitations of the protocol to access diarylmethanes have been demonstrated with more than 20 examples, showing acceptable tolerance to functional group and steric hindrance. Although electron-withdrawing substituents on benzotriazinone or benzyl counterparts decrease the yields significantly, a series of N-alkyl-2-benzylbenzamides, diarylmethanes bearing an ortho-carbamoyl aryl group, could be obtained in modest to good yields. Full article

Soluble organics (SBC-L) from Santanghu bituminous coal (SBC) were obtained by extracting the coal with a mixed solvent of CS₂ and acetone (v/v′ = 1:1). Catalytic hydrogenation of SBC-L was carried out using isopropanol as the solvent and prepared bimetallic material (Ni-Mo/γ-Al₂O₃) as the catalyst, and the hydrogenation product (SBC-L_IP320) was obtained. Gas chromatography-mass spectrometry (GC-MS) was used to compare the difference in the composition and distribution of SBC-L and SBC-L_IP320; thus, the effect of the used catalyst on the hydrogenation performance and heteroatom removal of SBC-L can be investigated. Results showed that the organic compounds in SBC-L and SBC-L_IP320 could be classified into aliphatic hydrocarbons (AHS), arenes, oxygen-containing organic compounds (OCOCs), nitrogen-containing organics (NCOCs), and compounds containing other heteroatoms (OHACOCs). The relative contents of AHS and arenes detected in SBC-L_IP320 were higher than those of SBC-L, while the contents of OCOCs, NCOCs, and OHACOCs decreased, and no S-containing compounds could be detected in SBC-L_IP320. It can be concluded that the prepared catalyst presents good de-oxygenation, de-sulfurization, de-nitrogenation, and hydrocracking performance. Full article

In this study, we investigated the pyrolysis of cellulose, lignin, phenylalanine and textile wool waste using microscale thermogravimetric analysis (TGA) and a gram-scale fixed bed reactor. The pyrolysis was conducted at 500 °C and 1 bar N₂, using Al- and Li-doped mesoporous KIL-2 and ZSM-5 catalysts for comparison. Our results show that amorphous Al-KIL-2 catalyst was the most efficient in producing aromatics from cellulose and lignin. This efficiency is attributed to Al-KIL-2 large mesoporosity, wide pore size distribution, and mild acid sites. Additionally, Al-KIL-2 promoted esterification and denitrogenation reactions, indicating its potential application in the pyrolysis of biomass and protein-rich feedstocks. Conversely, the Li-KIL-2 catalyst demonstrated activity primarily in the depolymerisation of cellulose to sugars and promoted ketonisation and alcohol formation. In summary, our findings indicate that Al-KIL-2 is a promising catalyst for efficient aromatic production from biomass. Full article

The removal of nitrogen compounds from fuel via the conventional method, which is hydrodenitrogenation, is costly and involves catalysts and energy-intensive conditions (600 K and 300 atm). Recently, ionic liquids (ILs) have emerged as a promising alternative solvent for the denitrogenation of fuel oil. However, certain ILs are expensive and challenging to synthesize, prompting the exploration of protic ionic liquid (PIL) substitutes, which offer similar advantages to ILs. This study utilized the conductor-like screening model for real solvents (COSMO-RS) to predict the phase equilibria for three PILs—triethylammonium p-toluenesulfonate (TEA-TSA), triethylammonium salicylate (TEA-SA) and triethylammonium benzoate (TEA-BZ)—which were subsequently validated through experimental investigations. Liquid–liquid extraction experiments were conducted at 298 K and 1 atm, with pyrrole (serving as the model nitrogen compound) concentrations in n-hexadecane (representing the model fuel) ranging from 10 to 50 wt%. Additionally, the NRTL model effectively correlated the experimental tie lines. The obtained data indicated that TEA-TSA exhibited superior selectivity and distribution ratio compared to TEA-SA and TEA-BZ. All the ternary systems tested displayed positive slopes, suggesting a higher affinity of nitrogen compounds for the PIL. Supporting this observation, interaction energy (ΔE) and excess enthalpy (H^E) were employed. The predicted outcomes revealed that TEA-TSA had high ΔE, and all PILs exhibited negative values of H^E. The H^E calculation underscored the significance of strong hydrogen bond interactions between pyrrole and the PIL for successful extraction. Full article

The removal of sulfur- and nitrogen-containing compounds present in fuels is and will be crucial to accomplish actual strict regulations to avoid environmental and humanity health adversities. The conventional hydrodesulfurization and hydrodenitrogenation processes conducted by refineries are limited due to severe operating conditions, and even more importantly, they are inefficient for simultaneously removing nitrogen- and sulfur-containing compounds in fuels. On the other hand, non-hydrogen technologies are beneficial in terms of mild operating conditions, and during the last two decades, some successful works have shown that these can be highly effective at efficiently removing both sulfur- and nitrogen-containing compounds from liquid fuels. For more than four decades, extensive research (thousands of publications since the 1980s) has been dedicated to developing remote desulfurization technologies without taking into consideration the presence of a complex fuel matrix, or even taking into account the presence of other harmful pollutant elements, such as nitrogen. Even more recently, several effective non-hydrogen denitrogenation processes have been reported without considering the presence of sulfur compounds. This review paper is a reflection on the limited work that has been successfully performed to simultaneously remove sulfur- and nitrogen-containing compounds from fuels. An evaluation of different methodologies (adsorption, extraction, oxidative (photo)catalysis, ultrasound-assisted oxidation) is presented here. Furthermore, this review intends to define new future strategies that will allow the design of more suitable and economical technologies, effectively conciliating desulfurization and denitrogenation processes to produce more sustainable fuels. Full article