Biochar carbon nanodots for catalytic acetalization of biodiesel by-product crude glycerol to solketal: process optimization by RSM and life cycle cost analysis

• Published in: Scientific reports Vol. 14; no. 1; pp. 20140 - 17
• Main Authors: Ao, Supongsenla, Gouda, Shiva Prasad, Saikia, Lakshi, Gurunathan, Baskar, Rokhum, Samuel Lalthazuala
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29-08-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 704/172; 704/844/843; Acetalization; Biochar; Biodiesel fuels; Biofuels; Carbon; Carbon cycle; Carbon-nanodots; Catalysts; Charcoal; Cost analysis; Diesel; Glycerol; Humanities and Social Sciences; Life cycle cost analysis; Life cycles; multidisciplinary; Science; Science (multidisciplinary); Solketal; Waste streams; Carbon-nanodots; Solketal; Acetalization; Life cycle cost analysis; Biochar
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-69553-7

Carbon-based nanodots have garnered recent interest for their simple synthesis and versatile utility, ranging from biomedical to (opto) electronic applications, evolving into a tunable and biocompatible material. Here, for the first time, a biochar (lotus leaf) derived carbon nanodots was synthesized through hydrothermal carbonization. The synthesized hollow spherical biochar was engineered via functionalization by grafting –SO
3
H active sites. The attained catalyst was broadly analyzed by XRD, FTIR, TGA, BET, SEM–EDX, TEM, and XPS analysis after which it was applied for the acetalization reaction of crude glycerol (a biodiesel by-product) to form solketal, a potential fuel additive to valorize the large waste stream generated from biodiesel industry. Employing the RSM-CCD methodology, the experimental matrix was executed, and subsequent data were scrutinized through multiple regressions to model a quadratic equation. Under specific reaction parameters—a reaction duration of 14 min, a molar ratio of 7.5:1, and a catalyst loading of 5.7 wt.%, maximum solketal yield (95.7%) was attained through the ultrasonication method. Finally, to conclude, life cycle cost analysis (LCCA) for solketal production was studied here which determined the overall cost of solketal production per kilogram to be 0.719 USD ($), indicating high commercial applicability.