Search Results (44)

To address the greenhouse effect and environmental pollution stemming from fossil fuels, the development of new energy sources is widely regarded as a critical pathway toward achieving carbon neutrality. Microalgae, as a feedstock for third-generation biofuels, have emerged as a research hotspot for producing biojet fuel due to their high photosynthetic efficiency, non-competition with food crops, and potential for carbon reduction. This paper provides a systematic review of technological advancements in the catalytic hydrogenation of microalgal oil for biojet fuel production. It specifically focuses on the reaction mechanisms and catalyst design involved in the hydrogenation–deoxygenation and cracking/isomerization processes within the Oil-to-Jet (OTJ) pathway. Furthermore, the paper compares the performance differences among various catalyst support materials and between precious and non-precious metal catalysts. Finally, it outlines the current landscape of policy support and progress in industrialization projects globally. Full article

Identifying suitable catalyst types and efficient loading methods remains a key research challenge for implementing the in situ catalytic pyrolysis of tar-rich coal. This study investigated a lignite and a gas coal, employing NiCl₂ solution for Ni²⁺ catalyst loading via room-temperature impregnation and hydrothermal treatment on coal particles sized 6–13 mm. The efficiency of Ni²⁺ loading through hydrothermal treatment and the characteristics of pyrolysis product distribution and composition before and after treatment were examined. The results indicated that after NiCl₂ solution impregnation, the Ni²⁺ content in lignite increased from nearly undetectable to over 20 mg/g, whereas in gas coal, it only rose to less than 2 mg/g. Ion exchange is hypothesized to be a primary pathway for Ni²⁺ loading into coal. After hydrothermal treatment at 170 °C, the Ni²⁺ loadings in lignite and gas coal reached 33.6 and 1.45 mg/g, respectively. The loaded Ni²⁺ exhibited distinct catalytic effects on the two coals. For lignite, Ni²⁺ catalyzed the deoxygenation of oxygen-containing compounds and the aromatization of aliphatic hydrocarbons. For gas coal, hydrothermal treatment with NiCl₂ solution at 170 and 220 °C promoted hydrogen transfer reactions, resulting in an increase in tar yield from 10.67% to 11.30% and 11.64%, respectively. Also, the H₂ yield decreased, accompanied by a decrease in aromatic hydrocarbons and an increase in phenolic compounds within the tar. Full article

This review overviews the efficient hydrophobization method of hydrophilic natural polymers, which has been developed by means of glucan phosphorylase (GP)-induced enzymatic grafting of unnatural heteropolysaccharides, that is, partially 2-deoxygenated (P2D)-amyloses. The enzymatic polymerization technique is well known as a useful approach to prepare polysaccharides with well-defined structures. The authors have found that the hydrophobicity of P2D-amylose, synthesized by the thermostable GP (from Aquifex aeolicus VF5)-induced enzymatic copolymerization of α-d-glucose 1-phosphate (Glc-1-P)/d-glucal as comonomers, started from maltooligosaccharide primers. Based on this finding, glycogen, a hydrophilic spherical natural polysaccharide, was hydrophobized by means of the thermostable GP-induced enzymatic functionalization of the P2D-amylose chains because glycogen acted as the polymeric primer for the GP catalysis. After introducing the maltooligosaccharide primers onto hydrophilic natural polymers with carboxylate groups—such as poly(γ-glutamic acid), carboxymethyl cellulose, and alginic acid—via chemical reactions, the thermostable GP-induced enzymatic copolymerization of Glc-1-P/d-glucal was carried out using the resulting polymeric primers, enabling their hydrophobization through the grafting of P2D-amylose chains (the chemoenzymatic approach). Moreover, the chemoenzymatic method has extensively been employed for hydrophobization of the surfaces on natural polysaccharide nanofibers, such as cellulose and chitin nanofibers. Full article

The potential of king grass biomass as a precursor for carbon-based materials was evaluated through comprehensive physicochemical characterization. The biomass showed high fixed carbon content, reactive oxygenated groups, and favorable atomic ratios, supporting its suitability for conversion into porous carbon structures. This study focused on the synthesis of graphene-like materials via high-temperature pyrolysis (~1000 °C), employing FeCl₃ and potassium ferricyanide (K₃[Fe(CN)₆]) as catalytic agents. Although FeCl₃ is widely studied, it showed limited capacity to promote graphitic ordering. In contrast, K₃[Fe(CN)₆] exhibited a synergistic effect, combining iron-based catalytic species (Fe, Fe₃C) and potassium-derived activating compounds (K₂CO₃), which significantly enhanced graphitization and porosity. Characterization by Raman spectroscopy, XRD, and SEM confirmed that materials synthesized with K₃[Fe(CN)₆] presented improved crystallinity, lower defect densities (I_D/I_G = 0.37–1.11), and distinct 2D bands (I_2D/I_G = 0.32–0.80), indicating the formation of few-layer graphene domains. The most promising structure was obtained from cellulose treated with alkaline peroxide and deoxygenated prior to pyrolysis with K₃[Fe(CN)₆], showing properties comparable to commercial graphene. BET analysis revealed surface areas up to 714.50 m²/g. While non-catalyzed samples yielded higher mass, the catalytic approach with K₃[Fe(CN)₆] demonstrates a sustainable and efficient pathway for producing graphene-like carbon materials from lignocellulosic biomass. Full article

This research contributes to advance the sustainable production of biofuels and provides insights into the energy and exergy assessment of bio-oil, which is essential for developing environmentally friendly energy production solutions. Energy and exergy analyses were performed to evaluate the pyrolysis of beech wood biomass at 500 °C in an Auger reactor. To improve the quality of the obtained bio-oil, its catalytic deoxygenation was performed within an in-line fluidized catalytic bed reactor using a catalyst based on HZSM5 zeolite modified with 5 wt.% Iron (5%FeHZSM-5). A thermodynamic analysis of the catalytic and non-catalytic pyrolysis system was carried out, as well as a comparative study of the calculation methods for the energy and exergy evaluation for bio-oil. The required heat for pyrolysis was found to be 1.2 MJ/kg_biomass in the case of non-catalytic treatment and 3.46 MJ/kg_biomass in the presence of the zeolite-based catalyst. The exergy efficiency in the Auger reactor was 90.3%. Using the catalytic system coupled to the Auger reactor, this efficiency increased to 91.6%, leading to less energy degradation. Calculating the total energy and total exergy of the bio-oil using two different methods showed a difference of 6%. In the first method, only the energy contributions of the model compounds, corresponding to the major compounds of each chemical family of bio-oil, were considered. In contrast, in the second method, all molecules identified in the bio-oil were considered for the calculation. The second method proved to be more suitable for thermodynamic analysis. The novelties of this work concern the thermodynamic analysis of a coupled system of an Auger biomass pyrolysis reactor and a fluidized bed catalytic deoxygenation reactor on the one hand, and the use of all the molecules identified in the oily phase for the evaluation of energy and exergy on the other hand. Full article

This work concerns the preparation of Pt/AC catalysts (Pt supported on activated carbon) and their application to the synthesis of hydrocarbon biofuels through the HEFA (hydroprocessing of esters and fatty acids) route. The key motivation for the work was that catalysts based on sulfided Mo supported on γ-Al₂O₃, traditionally employed in the hydroprocessing of petroleum derivatives, (i) are unstable in the HDO (hydrodeoxygenation) of biomass-derived feedstocks and (ii) can contaminate the resulting biofuels with sulfur. In this context, a systematic study on the effects of preparation conditions on the properties of the resulting Pt/AC catalysts and their performance in HEFA was carried out for the first time. Efficient catalysts were obtained, which led to the complete deoxygenation of lauric acid and coconut oil, yielding products composed primarily of n-alkanes. The highest HDO activity was verified for the catalyst prepared using as a support an AC previously subjected to thermal treatment up to 800 °C in a H₂ atmosphere (which removed most of the surface acidic oxygenated groups), depositing Pt over the surface of this support via wet impregnation using a H₂PtCl₆ solution acidified with HCl. The obtained results showed the great potential of the Pt/AC catalysts for the production of hydrocarbon biofuels through the HEFA route. Full article

Epoxide deoxygenation by photocatalysis was explored using Au-Co alloy nanoparticles supported on ZrO₂ under visible light irradiation. The active metals were deposited on commercial monoclinic ZrO₂ by chemical impregnation to achieve controlled mass ratios of gold and cobalt in the alloy nanoparticles. The characterisation of the alloy nanoparticles confirmed the technique produced an average particle size of 4.50 ± 0.29 nm. Catalysts containing pure 3% Au and different Au-Co metal ratios attached to the ZrO₂ induced the deoxygenation of styrene oxide in an isopropanol solvent medium. Only 20 mg of pure Au/ZrO₂ catalyst gave a 99% yield of styrene at an 80 °C temperature within 16 h under visible light irradiation (400–800 nm). Au-Co/ZrO₂ catalysts generally induced conversion to styrene under the same conditions below 60 °C. Above 60 °C, a new reaction pathway was observed to favour a different product over Au-Co/ZrO₂, which was identified as styrene glycol. This study developed a new approach to the synthesis of styrene glycol, a molecule that has many useful applications in the chemical and polymer industries. Surface-enhanced Raman spectroscopic (SERS) studies and electron paramagnetic resonance spectroscopic (EPR) studies identified changes in the reaction mechanism and pathway upon increasing the cobalt molar ratio in the Au-Co alloy catalysts. Full article

At the steelmaking temperature, carbon has a strong deoxidation ability. Under the vacuum condition, its deoxidation ability can be further improved, and it can become a stronger deoxidation element than aluminum. The product of carbon deoxygenation is CO, which floats up and detaches from the molten steel in the form of bubbles and does not produce oxide inclusions. Under normal pressure, replacing aluminum with carbon to complete partial deoxidation tasks can not only reduce the generation of inclusions and alleviate the pressure of removing inclusions, but also reduce the consumption of aluminum and save deoxidation costs. In this study, the carbon deoxidation process after the converter was investigated. Firstly, the timing of carbon addition was determined through thermodynamic calculations, and it was found that, in oxygen-enriched molten steel, the priority of the reaction of the deoxidation element was [Al] > [Si] > [C] > [Mn]. Through the carbon and oxygen balance calculation, it is known that the carbon deoxidation effect is greatly affected by the carbon content of the molten steel; for low-carbon steel, carbon can be used for pre-deoxygenation, whereas for medium-carbon and high-carbon steel, carbon can complete most of the deoxidation tasks. Finally, with 45 steel as the research object, the carbon deoxidation process was designed and tested in industry. The results showed that, compared with the aluminum deoxidation process, the number of inclusions in the billet casting of the carbon deoxidation process was reduced by 68.8%, and the carbon deoxidation process had fewer large-sized inclusions in the billet casting. In addition, the carbon deoxidation process uses carbon powder instead of the aluminum block for deoxidation during steel tapping from the converter. The deoxidant cost is reduced by CNY 15.47/ton of steel. From a comprehensive point of view, the application of carbon deoxidation after the converter can reduce aluminum consumption and improve the cleanliness of steel, which is an important way for enterprises to reduce costs and increase efficiency. Full article

Bio-oil is a potential source for the production of alternative fuels and chemicals. In this work, Ni-V bimetallic zeolite catalysts were synthesized and evaluated in in situ catalytic hydrodeoxygenation (HDO) of pyrolysis volatiles of pine nut shell for upgraded bio-oil products. The pH and lower heating value (LHV) of the upgraded bio-oil products were improved by in situ catalytic HDO, while the moisture content and density of the oil decreased. The O/C ratio of the upgraded bio-oil products decreased significantly, and the oxygenated compounds in the pyrolysis volatiles were converted efficiently via deoxygenation over Ni-V zeolite catalysts. The highest HDO activity was obtained with NiV/MesoY, where the obtained bio-oil had the lowest O/C atomic ratio (0.27), a higher LHV (27.03 MJ/kg) and the highest selectivity (19.6%) towards target arenes. Owing to the more appropriate pore size distribution and better dispersion of metal active sites, NiV/MesoY enhanced the transformation of reacting intermediates, obtaining the dominant products of phenols and arenes. A higher HDO temperature improved the catalytic activity of pyrolysis volatiles to form more deoxygenated arenes. Higher Ni loading could generate more metal active sites, thus promoting the catalyst’s HDO activity for pyrolysis volatiles. This study contributes to the development of cost-efficient and eco-friendly HDO catalysts, which are required for producing high-quality biofuel products. Full article

The global energy crisis is associated with the need to search for low-energy technical solutions. Such solutions are also introduced in the field of protection and restoration of surface waters. The aim of this work was to determine the efficiency of the AS15000 pulverizing aerator powered by solar energy. The innovative solutions of the aerator presented in this manuscript are subject to a patent application. A simulation was carried out taking into account the efficiency of the aerator pump and the sunlight conditions for the indicated location. The analysis was carried out for the location of an artificial reservoir—Zalew Średzki in Środa Wielkopolska (Poland). The simulation showed that during 6515 h of aerator operation, the pulverizing system pumped as much as 97,725 m³ of lake water. The amount of pure oxygen introduced into the water during the operation of the device can be as much as 1074.98 kg. The minimum daily value of sunlight enabling continuous operation of the device (24 h a day) with maximum efficiency is 1.43 kW/m². Deoxygenated water in the pulverizing aeration process is taken from the bottom zone, transported to the surface and sprayed in the atmospheric air. Oxygenated water is intercepted and discharged to the bottom zone. Developing artificial aeration methods for lakes in combination with renewable energy sources is very important for improving water quality. The use of solar power allows the device to be used when it is far from the power infrastructure. This also allows the installation of aerators in the middle of the lake. In accordance with the Water Framework Directive, we should strive to improve the water quality of many European lakes as quickly as possible. Full article

Butachlor is a widely utilized acetamide herbicide noted for its systemic selectivity against pre-emergence grass weeds. Butachlor has negative effects on organisms and the environment, so it is necessary to screen degradation strains. In this investigation, Bacillus cereus strain DC-1 was isolated from soil persistently exposed to butachlor. Through rigorous single-factor and response surface analyses, strain DC-1 exhibited a notable 87.06% degradation efficiency under optimized conditions where the temperature was 32.89 °C, pH was 7.29, and inoculum concentration was 5.18%. It was further hypothesized by LC-MS that the degradation pathway of butachlor by strain DC-1 might be as follows: butachlor undergoes initial deoxygenation catalyzed by dioxygenases to form 2-chloro-N-(2,6-diethylphenyl)-N-methylacetamide, followed by N-demethylation yielding 2-chloro-N-(2,6-diethylphenyl) acetamide, and culminating in conversion to 2,6-diethylphenol. In addition, bioremediation experiments of butachlor-contaminated soil were conducted. The results show that strain DC-1 could degradable 99.23% of butachlor (100 mg·kg⁻¹) from the soil within 12 d, and soil sucrase, cellulase, and urease activities are promoted by the bacteria. And through high-throughput sequencing, it was concluded that the strain DC-1 was able to influence the relative abundance of certain bacteria in the soil, and make the microbial community in the soil develop in a more stable and beneficial direction. DC-1 thus represents a valuable resource in the realm of butachlor degradation due to its robust efficacy, favorable characteristics, and ecological restorative capabilities, underscoring its promising role in the bioremediation of butachlor-contaminated soils. Full article

This study investigates a continuous deoxygenation of bio-oil vapor in a catalytic fixed-bed reactor coupled to a continuous drop tube reactor (DTR) for biomass pyrolysis. Beech wood pyrolysis was initially examined without catalysts at various temperatures (500–600 °C). The products were characterised using GC-MS, Karl Fischer titration, GC-FID/TCD, and thermogravimetric analysis. The highest bio-oil yield (58.8 wt.%) was achieved at 500 °C with a 500 mL/min N₂ flow rate. Subsequently, ex situ catalytic pyrolysis was performed using an HZSM-5 catalyst in a fixed-bed reactor at a DTR outlet, operating at 425 °C, 450 °C, and 500 °C. The HZSM-5 catalyst exhibited declining deoxygenation efficiency over time, which was evidenced by decreasing conversion rates of chemical families. Principal component analysis was employed to interpret the complex dataset, facilitating a visualisation of the relationships between the experimental conditions and product compositions. This study highlights the challenges of continuous operation as experimental durations were limited to 120 min due to clogging issues. This research contributes to understanding continuous biomass pyrolysis coupled with catalytic deoxygenation, providing insights into the reactor configuration, process parameters, and catalyst performance crucial for developing efficient and sustainable biofuel production processes. Full article

The development of effective catalytic systems for deoxygenation reactions is critical to the conversion of renewable feedstocks into sustainable fuels. In this work, the influence of various reaction parameters on the conversion of palmitic acid into alkanes, such as temperature, stirring rate, reaction time, H₂ pressure, amount of catalyst and substrate concentration was evaluated using the commercial Co-Mo/Al₂O₃ catalyst. In parallel, bimetallic Co-Mo catalysts supported on carbon nanotubes (CNTs) were prepared and characterized using various techniques, and their catalytic performance was assessed under the optimized conditions. The results showed that palmitic acid can be efficiently converted at 350 °C for 6 h at 30 bar H₂ pressure, stirring at 150 rpm and using 0.25 g of catalyst and 0.50 g of palmitic acid in 50 mL of n-decane. Under these conditions, a complete substrate conversion and yields of 89.4 and 4.8% of C₁₆ and C₁₅ were achieved. In addition, Co-Mo/CNT_ox presented a similar catalytic performance as the commercial one, with a final result of 90.9% yield in C₁₆. These findings point out the potential of using Co-Mo/CNT_ox as a competitive alternative to liquid fuel production. Full article

Aiming at problems such as low energy utilization efficiency and the high oxygen content of liquid products in the process of conventional biomass conversion to prepare liquid fuels, the deoxygenation pyrolysis technology route of larch based on microwave heating was proposed in this paper. Two kinds of calcium–iron composite oxygen carriers, including Ca₂Fe₂O₅ with iron ore structure and CaFe₂O₄ with spinel structure, were successfully synthesized. The results showed that the selectivity of ideal products was improved under the action of single iron-based oxygen carriers; however, the deoxygenation effect was undesirable. Under the action of CaFe₂O₄, the selectivity of aromatics was increased to 27.17% and the selectivity of phenols was decreased to 36.46%, which mainly existed in the form of O₁P with low oxygen content. The oxygen content of bio-oil was reduced to 27.70% and the calorific value was increased to 29.05 MJ/kg, thus leading to a great improvement in the quality of liquid products. After the pyrolysis reaction, the Fe2P_3/2 XPS peak of CaFe₂O₄ shifted to a higher binding energy and was characterized as higher valence of iron oxide, which proved its “oxygen grabbing” capacity in microwave pyrolysis. The deoxygenation conversion of larch without an external hydrogen supply was achieved. Full article

The deoxygenation process in water used in well injection operations is an important matter to eliminate corrosion in the petroleum industry. This study used molecular dynamics simulations to understand the behavior of siloxane surfaces by studying the surface properties with two functional groups attached to the end of siloxane and their effect on the deoxygenation process. The simulations were performed using LAMMPS to characterize surface properties. Jmol software version 14 was used to generate siloxane chains with (8, 20, and 35) repeat units. We evaluated properties such as total energy, surface tension, and viscosity. Then, we used siloxane as a membrane to compare the efficiency of deoxygenation for both types of functional groups. The results indicated that longer chain lengths increased the total energy and viscosity while decreasing surface tension. Replacing methyl groups with trifluoromethyl (CF3) groups increased all the above mentioned properties in varying proportions. Trifluoromethyl (CF3) groups showed better removal efficiency than methyl (CH3) groups but allowed more water to pass. Furthermore, the simulations were run using the class II potential developed by Sun, Rigby, and others within an explicit-atom (EA) model. This force field is universally applicable to the atomistic simulation of polymers, inorganic small molecules, and common organic molecules. Full article