Sulfonated biochar catalyst derived from eucalyptus tree shed bark: synthesis, characterization and its evaluation in...

Area of Science:

• Catalysis
• Green Chemistry
• Materials Science

Background:

• Fatty acid methyl ester (FAME) production is crucial for biofuels.
• Developing efficient and sustainable solid acid catalysts is essential for esterification reactions.
• Biochar derived from biomass offers a promising platform for catalyst support due to its porous structure and functionalizability.

Purpose of the Study:

• To synthesize and characterize a sulfonated biochar catalyst from eucalyptus tree shed bark for oleic acid esterification.
• To optimize the esterification conditions for maximizing fatty acid methyl ester (FAME) yield.
• To evaluate the catalytic activity, stability, and reusability of the developed solid acid catalyst.

Main Methods:

• Sulfonation of activated biochar derived from eucalyptus bark using p-Toluenesulfonic acid (p-TSA).
• Esterification of oleic acid (OA) with methanol using the prepared p-TSA3/ABC catalyst.
• Optimization of reaction parameters including temperature, time, methanol/OA molar ratio, and catalyst dosage.
• Characterization of catalyst properties, including acidity and surface functional groups.
• Recycling experiments to assess catalyst stability and reusability.

Main Results:

• The p-TSA3/ABC catalyst, prepared with 6 g of p-TSA on 2 g of activated biochar, achieved a high FAME yield of 97.05 ± 0.28% under optimal conditions (65 °C, 2 h, methanol/OA ratio of 10:1, 4 wt% catalyst).
• The catalyst exhibited high acidity (468.8 μmol g⁻¹) with a dominance of SO3H acid sites, contributing to its remarkable performance.
• The p-TSA3/ABC catalyst demonstrated good stability, with no significant decrease in catalytic activity after five successive recycling cycles.

Conclusions:

• Sulfonated biochar derived from eucalyptus bark is an effective and stable solid acid catalyst for the efficient production of fatty acid methyl ester from oleic acid.
• The optimized esterification process offers a sustainable route for FAME synthesis with high yields.
• The reusability of the catalyst highlights its potential for industrial applications in biofuel production.