Preparation and Characterization of Alkaline and Acidic Heterogeneous Carbon-Based Catalysts and Their Application in Vegetable Oil Transesterification to Obtain Biodiesel

Abstract

This paper reports the preparation, evaluation, and comparison of alkaline and acidic heterogeneous carbon-based catalysts in the transesterification of safflower oil with methanol to obtain biodiesel. These catalysts were obtained from the pyrolysis of flamboyant pods and their functionalization and activation with potassium hydroxide, citric acid, tartaric acid, sulfuric acid, and calcium nitrate. Different routes for the preparation of these catalysts were tested and analyzed where the FAME formation was the target variable to be improved. Results showed that the catalyst prepared with potassium hydroxide and calcium nitrate achieved the highest FAME formation (i.e., 95%) and outperformed the catalysts prepared with calcium nitrate and other acids even after four regeneration-reaction cycles. The best properties of an alkaline catalyst could be associated with its specific surface area and contents of potassium and calcium moieties, which were higher than those observed for acidic catalysts. Transesterification rates for biodiesel production were better estimated with the pseudo-order kinetic model, which ranged from 0.0004 to 0.038 L/mol⋅min for alkaline and acidic catalysts.

Glycerol-Based Retrievable Heterogeneous Catalysts for Single-Pot Esterification of Palm Fatty Acid Distillate to Biodiesel

“…Figure 3 reveals the infrared absorption spectra of glycerol in samples that scanned from 4000 to 400 cm −1 at room temperature. Infrared vibration absorptions of C-H stretching were displayed at 2923 cm −1 and 2850 cm −1 , indicating the asymmetric CH 2 and symmetric CH 2 stretching mode, respectively [ 29 ]. An intense IR absorption spectrum at 1691 cm −1 was assigned to C=O absorption band [ 30 ].…”

Synthesis and characterization of polypyrrole composites: Optimization strategies for tailored material qualities and enhanced applications

“…The versatility of polypyrrole is further enhanced through the incorporation of various composites. Combinations with nanoparticles, carbonbased materials, or other polymers contribute to synergistic effects, offering improved mechanical strength, enhanced conductivity, and expanded functionality (Díaz-Muñoz et al, 2022; Kamalov et al, 2022;Krishna Prasad et al, 2022;Nanoparticles et al, 2023) [6,13,14,15] . The study systematically investigates the impact of different composite formulations on the overall performance of the materials, elucidating the mechanisms underlying their enhanced properties.…”

A Guinea Fowl Eggshells Derived Calcium Oxide Catalyst for Transesterification of Coconut Oil

“…Biodiesel production utilizes oil or fat and short-chain alcohol in the presence of either homogeneous or heterogeneous catalysts. Heterogeneous catalysts have attracted greater attention due to, among others, there is no need to wash the biodiesel product to remove the catalyst, the possibility of catalyst regeneration, and the catalyst is noncorrosive and economical, giving them an advantage for industrial applications [12]. According to the Equations (1-3) of Trans-esterification of a triglyceride, for every one mole of triglyceride three moles of alcohol are required, but the equilibrium nature of the reaction obliges higher moles of alcohol to obtain high ester yields, depending on the reaction parameters; oil and catalyst type, reaction temperature, etc [9].…”