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The present study focuses on the novel synthesis of cerium oxide (CeO 2) nanoparticles from cerium nitrate hexahydrate by using Azadirachta indica (neem) leaf extract. The parameters associated with the green synthesis process were optimized utilizing the response surface methodology (RSM) paired with the genetic algorithm (GA) to produce a higher yield rate. The experiment run order for the CeO 2 green synthesis is then generated using the central composite design in RSM. The regression equation was used as an optimization function, and the optimal values were identified through GA. Using optimized input process parameters, 0.3 g/10 mL of precursor concentration and 5 mL of Azadirachta indica leaf extract centrifuged for 20 min in the green synthesis process resulted in a maximum yield of 15.49 % CeO 2 nanoparticles. The synthesized CeO 2 nanoparticles are characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), particle size distribution, and zeta potential analyses, which are used to ensure their presence in the green synthesis process. Subsequently, the green synthesized CeO 2 nanoparticles are dosed as an additive to the cotton seed biodiesel (CSB) at different proportions of 25, 50, and 75 ppm, respectively. The prepared biofuel's physico-chemical properties were measured as per ASTM standards and are closer to the diesel fuel. As a result, it was noted that optimizing the green synthesis process parameters gives a maximum rate of CeO 2 yield. It is possible to efficiently use the CSB with CeO 2 nanoparticles as a suitable replacement for diesel fuel. [Display omitted] • Novel leaf extract for the sustainable synthesis of CeO 2 nanoparticles. • Green synthetic CeO 2 yield forecasted by RSM's central composite design. • A hybrid RSM-genetic algorithm approach to process parameters optimization. • A characterization study was done on environmentally friendly CeO 2 nanoparticles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Yellow grease enhanced bio-crude yields and lowered asphaltene content. • Feedstock selection can be used to tailor viscosity, density, and compatibility. • Food waste bio-crude showed regions of compatibility at higher concentrations. • Heterogeneous nature of wastes could lead to varied properties and behavior. Low quality waste feedstocks like food wastes, waste fats, manures etc. offer huge potential for replacing an appreciable quantity of petroleum crude. Owing to high water content of some of these feedstocks, hydrothermal liquefaction is the preferred route for its transformation. The present work performed in a continuous pilot scale hydrothermal liquefaction system studies the influence of yellow grease on the yields and quality of bio-crude, properties of bio-crude/blends, and its compatibility with petroleum fractions. Blends of food waste, yellow grease, and algae were used as feedstocks. Key fuel properties such as density and viscosity of bio-crudes and its blends with diesel and butanol were evaluated. Compatibility of different bio-crudes with petroleum fraction was investigated using microscopy imaging of blends of bio-crude and commercial diesel. Enhanced yields of bio-crude and lower asphaltene content were observed with the addition of waste lipids in the form of yellow grease while also decreasing the viscosity and density of bio-crude. Bio-crude from food wastes showed regions of compatibility at higher bio-crude concentrations while lower concentrations of bio-crude were incompatible. A combination of feedstock mix and blending of bio-crude could be used to improve the properties and compatibility of bio-crude for specific end-use devices and processes. [ABSTRACT FROM AUTHOR]

The use of organic wastes as new renewable energy sources is becoming necessary to achieve the growing energy demand in Tunisia. In this work, the pyrolysis of abundant waste fish fats provided by a canned Tuna factory was examined in a laboratory fixed-bed reactor. The main objective was to analyze the properties and the composition of the produced bio-oil using in order to implement the suitable valorization strategy. Therefore, high heating value, viscosity, density, flash point, acidity index, moisture content and ash content measurements as well as FTIR and GCMS analyses were carried out to characterize the pyrolytic oil obtained during waste fish pyrolysis at 500 °C. The obtained results revealed that waste fish fats can be considered as important feedstock for biofuel production. In particular, the bio-oil characterization showed the presence of many organic compounds such as alkanes, alkenes, alkynes, cyclic hydrocarbons, carboxylic acids, aldehydes and alcohols. These compounds could be used as a valuable and sustainable chemicals source. Moreover, the bio-oil properties indicated a good calorific value (~ 9391 kcal/kg) compared to Tunisian Diesel and European biodiesel specifications. In contrast, higher acidity (~ 103 mg KOH/g sample) and viscosity (~ 7 cSt) compared to conventional fuels were obtained. These properties limit the direct use of bio-oils as alternative fuel in a Diesel engine. An efficient mixture with fossil fuel may be a promising solution to improve the fuel properties. Hence, pyrolysis seems to be an eco-friendly process to recover the fish fatty wastes in Tunisia. The implementation of such management strategy will help Tunisian agri-food industries to reduce their environmental impact and fossil fuel consumption and to promote the renewable energy use. [ABSTRACT FROM AUTHOR]