Prospects and Challenges of Microwave-Combined Technology for Biodiesel and Biolubricant Production through a Transesterification: A Review

Effect of solar powered MgO/graphene nano catalysed biodiesel production from Scomber scombrus

The aim of the work is to find the efficiency of solar power in biodiesel preparation from mackerel fish. The paper also focusses on the ability of MgO/graphene prepared by one-pot synthesis using combustion methodology. The physicochemical properties of the material were analysed by XRD, N2 sorption studies, BET sorption analysis and SEM. The adsorption studies revealed the porosity of the graphene is intact, and the morphology studies indicated that MgO is uniformly distributed on the graphene surface. The highest biodiesel yield of 98.95% was obtained using the solar-powered Fresnel solar concentrator at 12.30 p.m in 6 min reaction time using 3 wt% MgO/GO catalyst at 65 °C. Conventional heating produced only 75% biodiesel at the same reaction condition, consuming25 min to complete. The solar assisted biodiesel had better HHV of 37.81 MJ/Kg, viscosity of 4.3 mm2/s, pour point of -15 °C, and a density of 0.875 g/mL. The optimized catalyst showed a shelf life of 5 cycles. The results portray the efficacy of natural energy source in alternative liquid fuel production.

Sustainable Green Route for Activated Carbon Synthesis from Biomass Waste for High-Performance Supercapacitors

Supercapacitors are high-power energy storage devices due to their charge storage capability and long cyclic stability. These devices rely on highly porous materials for electrodes providing a substantial surface area per mass, such as highly porous carbon. Developing high-performance porous carbon from biomass wastes such as waste-activated sludge and spent coffee is a sustainable way to reduce adverse environmental effects, contributing toward a carbon circular economy. In this study, hierarchically porous carbon with a high surface area of 1198 ± 60 m2 g-1 was synthesized through a green route. Sodium acetate was utilized as an environmentally friendly electrolyte. The long-term stability test at a high current density was conducted, providing valuable insights into the viability of sodium acetate as a robust electrolyte in supercapacitor application. The supercapacitor demonstrated an excellent cycle stability of 98.4% after 20,000 cycles at a current density of 10 A g-1 in sodium acetate. Further assessment revealed dominant fast surface kinetics. Moreover, a maximum energy density of 15.9 Wh kg-1 at 0.2 A g-1 was achieved. By utilizing highly porous carbon in conjunction with a water-based binder, a substantial improvement of 76% in capacity with respect to a nonaqueous-based binder was demonstrated.

A review on recent biodiesel intensification process through cavitation and microwave reactors: Yield, energy, and economic analysis

The use of biodiesel as a reliable and green energy source has grown over the past few years. Biodiesel is sustainable and biodegradable because it is only made from vegetable contents and waste cooking oil. Although biodiesel has many advantages over conventional fuels, there are still a lot of technological issues that need to be addressed during the production process. The yield of biodiesel produced using conventional methods is poor and the process is time-consuming. Process enhancements like cavitation and microwave have thus been developed to address this problem. Starting with a comparison to the conventional biodiesel process, this paper has reviewed the most recent developments in the increase of mixture and transfer of heat in these two reactors. This paper examined biodiesel improvement using microwave and cavitation reactors, including biodiesel yield, by meticulously reviewing and analyzing previous works. The production of biodiesel from various raw materials using a range of catalysts, energy requirements, as well as operating factors, activation energy, and constraints also have been discussed. Additionally, the economic analysis discusses the feasibility and cost-effectiveness of implementing these technologies on a commercial scale. Overall, this review provides valuable insights into the intensification of biodiesel production using cavitation and microwave reactors while considering both the technical and economic aspects.

Synthesis and Activity of Ionic Antioxidant-Functionalized PAMAMs and PPIs Dendrimers

For this study, new dendrimers were prepared from poly(propylene imine) (PPI) and polyamidoamine (PAMAM) dendrimers using an efficient acid-base reaction with various phenolic acids. The syntheses were also optimized in both microwave and microfluidic reactors. These ionic and hydrophilic dendrimers were fully characterized and showed excellent antioxidant properties. Their cytotoxic properties have been also determined in the case of fibroblast dermal cells.

Microwave-assisted synthesis of trimethylolpropane triester (bio-lubricant) from camelina oil

Vegetable oils, whose hydrocarbon structure is very similar to that of petroleum products, are ideal renewable and sustainable alternatives to petroleum lubricants. Bio-lubricants are commonly synthesized by modifying the chemical structure of vegetable oils. In this study, microwave irradiation was applied to intensify the mass-transfer-limited transesterification reaction to produce trimethylolpropane triester (bio-lubricant) from camelina oil as a promising local energy crop. A rotatable RSM-BBD method was applied to find the optimal levels of experimental factors, namely reaction time (67.8 min), the catalyst concentration (1.4 wt%) and the molar ratio (3.5). In these optimal levels, the reaction yield of 94.3% was obtained with desirability of 0.975. The quadratic statistical model with a determination coefficient of 97.97%, a standard deviation of 0.91 and a variation coefficient of 1% was suggested as the most appropriate model by Design-Expert software. Finally, the physicochemical properties of the purified product were in accordance with the requirements of the ISO-VG22 base oil standard.

Current State and Perspectives on Transesterification of Triglycerides for Biodiesel Production

Triglycerides are the main constituents of lipids, which are the fatty acids of glycerol. Natural organic triglycerides (viz. virgin vegetable oils, recycled cooking oils, and animal fats) are the main sources for biodiesel production. Biodiesel (mono alkyl esters) is the most attractive alternative fuel to diesel, with numerous environmental advantages over petroleum-based fuel. The most practicable method for converting triglycerides to biodiesel with viscosities comparable to diesel fuel is transesterification. Previous research has proven that biodiesel–diesel blends can operate the compression ignition engine without the need for significant modifications. However, the commercialization of biodiesel is still limited due to the high cost of production. In this sense, the transesterification route is a crucial factor in determining the total cost of biodiesel production. Homogenous base-catalyzed transesterification, industrially, is the conventional method to produce biodiesel. However, this method suffers from limitations both environmentally and economically. Although there are review articles on transesterification, most of them focus on a specific type of transesterification process and hence do not provide a comprehensive picture. This paper reviews the latest progress in research on all facets of transesterification technology from reports published by highly-rated scientific journals in the last two decades. The review focuses on the suggested modifications to the conventional method and the most promising innovative technologies. The potentiality of each technology to produce biodiesel from low-quality feedstock is also discussed.