An excellent sulfonated hydrothermal carbon catalyst from Mangifera indica L. (mango peels) for biodiesel production: preparation, characterization, optimization, and kinetic study

• Published in: Biomass conversion and biorefinery Vol. 12; no. 1; pp. 141 - 151
• Main Authors: Memon, Safia S., Memon, Najma, Memon, Shahabuddin, Lachgar, Abdesaddek
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2022; Springer Nature B.V
• Subjects: Biodiesel fuels; Biotechnology; Carbon; Catalysis; Catalysts; Catalytic activity; Chemical synthesis; Density; Energy; Esterification; Fatty acids; Functional groups; Mangoes; Oleic acid; Optimization; Original Article; Renewable and Green Energy; Sulfuric acid; Surface area; Reusability; Hydrothermal carbon material; Oleic acid; Esterification; Mango peels
• ISSN: 2190-6815; 2190-6823
• DOI: 10.1007/s13399-021-01535-5

The current study describes the preparation and catalytic activity evaluation of newly synthesized hydrothermal carbon catalysts for biodiesel production. The catalysts (HTCC-M 2-10h ) were prepared through the sulfonation of mango peels ( Mangifera indica L. ) using concentrated sulfuric acid at various time intervals from 2- to 10-h process. The catalysts were characterized via sophisticated analytical techniques to analyze surface area, functional groups, morphology, and acid density sites. The catalyst prepared at a 6-h time interval shows a high density of proton switchable/acidic sites attached to the carbon surface (i.e., SO 3 H, COOH, and OH). The catalyst was found to exhibit a large surface area (42.13 m 2 /g), well-ordered porosity, and large pore volume. The catalytic activity was determined by examining the catalyst performance for fatty acid esterification to produce the methyl ester (i.e., biodiesel). Thus, HTCC-M 6h (prepared at 6 h) gives the maximum catalytic activity due to its high acid density (3.46 mmol/g) and large surface area. The maximum 98.6% oleic acid conversion into methyl oleate was obtained at 65 °C by using 10:1 v/v methanol:oil and 5 wt% of catalyst within 4 h. The kinetic study for oleic acid esterification by HTCC-M 6h performed at temperatures between 40 and 70 °C confirmed the first-order reaction as is the case for homogeneous esterification reaction. The recyclable ability of catalyst was also determined and found that the catalyst has enough potential to recycle up to four times without any reactivation step and any activity loss after that catalyst can be regenerated. The results revealed that the HTCC-M 6h exhibits high stability, high catalytic activity, and reusability. It could be concluded that the prepared HTCC-M 6h will prove itself an innovation in heterogeneous catalysis.