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Background: The transition from fossil-derived jet fuels to sustainable aviation fuels represents one of the most viable strategies to decarbonize air transport and mitigate CO2 emissions generated by fossil fuel combustion. In the present investigation, a catalytic hydroprocessing upgrading approach was used to transform Yellow Dodolla oil—one of the most prominent inedible Brassica carinata vegetable oils (indigenous to Ethiopia)—into bio-jet fuel. Methods: The feedstock was upgraded to jet fuel through catalytic hydroprocessing under elevated hydrogen pressure (21 bar), varying temperatures (300 and 500 °C), and employing supported carbon-coated mesoporous and crystalline nanocatalysts (β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18) in a laboratory-scale continuous three-phase fixed-bed reactor system. Other variables, such as the volumetric flow rate of oil feedstock, volumetric flow rate of hydrogen gas, hydrogen gas-to-oil ratio, catalyst-to-oil ratio, liquid hourly space velocity, weight hourly space velocity, and residence time, were maintained constant throughout the experimental procedure. Subsequent to an in-depth evaluation of catalytic performance parameters (conversion, selectivity, yield, and deoxygenation rate), a detailed characterization of the liquid phase products was undertaken to explore their most significant properties. Results: The analysis results demonstrated that the catalytic hydroconversion of the feedstock resulted in a conversion range of 71.57–79.76 wt.%, with the highest conversion of 79.76 wt.% achieved by Ni3C/AlPO4–18 at the maximum temperature. Moreover, the rate of deoxygenation varied from 8.08 to 11.67 wt.% at 300 °C, with nickel catalyst reaching the maximum rate, while it sharply rose to vary from 57.31 to 96.67 wt.% using molybdenum as the temperature increased to 500 °C. It was also discovered that in comparison to bio-gasoline (2.63–8.72 wt.%) and biodiesel (1.18–4.58 wt.%), bio-jet fuel (C8–C16) had noticeably higher yields (23.34–27.31 wt.%), selectivity (37–45 wt.%), and a superb hydrocarbon product distribution (C9–C16) at the maximum temperature, with WC/AlPO4-18 producing the highest yields and selectivity of jet fuel. The characterization results revealed that the hydrocracked liquid products possessed virtually identical physicochemical properties, chemical compositions, hydrogen-to-carbon atomic ratios (1.90–1.92), oxygen-to-carbon atomic ratios (0.002–0.030), and gravimetric energy densities (41.35–42.89 MJ kg−1) to those of conventional jet fuels. Conclusions: The conclusions of the study demonstrated that the non-food Yellow Dodolla oil was successfully hydrocracked into sustainable aviation fuel using AlPO4-18 supported metal carbide catalyst nanoparticles under the right reaction conditions and reactor system, potentially supporting the significant efforts of the aviation industry to lower its carbon footprint. [ABSTRACT FROM AUTHOR]

Developing high-efficiency, high-stability, and low-cost deoxygenation and hydrocracking catalysts could be considered one of the most significant breakthroughs in catalytic hydroprocessing. The present study utilized aluminophosphate (AlPO4-18), a zeolite-like molecular sieve, as catalyst support for producing carbon-coated β-Mo2C, Ni3C, and WC nanoparticles. The synthesis used an incipient wetness impregnation followed by a temperature-programmed reduction-carburization approach which involved cracking a hydrocarbon gas, propane, in a hydrogen environment. The synthesis parameters were a 1:7 propane/hydrogen reductive-carburizing gas stream, 15 wt.% metal loading, an 800 °C carburization temperature ramped-up at a heating rate of 10 °C min−1, a 2-h holding time, and a 1-h holding time in hydrogen. The synthesized catalysts were characterized using thermogravimetry mass spectroscopy/temperature-programmed oxidation (TPO TG-MS), nitrogen physisorption at 77 K, X-ray diffraction (XRD), and transmission electron microscopy/energy-dispersive X-ray spectroscopy (TEM EDS). TPO TG-MS, nitrogen physisorption, TEM, and XRD characterization results proved that atomic carbon was successfully incorporated into the lattice interstitials, resulting in thermally stable, well-dispersed, crystalline and mesoporous β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18 nanoparticles. XRD analysis showed structural evolution during reduction-carburization, with average crystallite sizes of metal-containing particles of 8.2–9.22, 6.64–8.50, and 6.03–7.56 nm for β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18, respectively. These values did not significantly deviate from high-resolution TEM analysis. The surface areas of the nanoparticles were categorized in decreasing order as WC/AlPO4-18 > Ni3C/AlPO4-18 > β-Mo2C/AlPO4-18, with values of 193.79, 169.05, and 66.57 m2 g−1, respectively. In conclusion, these carbon-coated metal carbide nanoparticles with excellent thermal, structural, microscopic, and textural properties can be viable alternatives to noble metal catalysts for producing bio-jet fuel using the hydroprocessing pathway. [ABSTRACT FROM AUTHOR]

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A novel, simple, fast, cheap and pollution free method for utilizing waste X-ray film for silver recovery using sodium hydroxide and sodium sulfide by the stripping and precipitation processes, respectively has been reported. The yield of silver by this process is 1.07% w/w at a stripping temperature of 70.88°C, 10.97 min and NaOH concentration of 1.5M. The composition of recovered silver has been determined by XRF and the results are compared with existing literature for the purity of silver. The study warrants the application of NaOH and Na2S to recover silver from used X-ray photographic film. [ABSTRACT FROM AUTHOR]