Integrated experimental and life cycle assessment of biodiesel production from Datura stramonium seed oil using a one-pot sulfonated corncob catalyst

This study presents a combined experimental and life cycle assessment of the production of biodiesel from Datura stramonium (DS) seed oil, using a one-pot sulfonated corn-cob solid acid catalyst. The catalyst, synthesized through simultaneous hydrothermal carbonization and sulfonation using sulfuric acid (H₂SO₄), was characterized by Fourier Transform Infrared Spectroscopy (FTIR), showing -SO₃H functionalization; X-ray Diffraction (XRD), indicating an amorphous carbon structure; and Brunauer-Emmett-Teller (BET) surface analysis showed 1.53 m²/g surface area, while the catalyst acidity was determined by titration, yielding 1.79 mmol/g. The esterification/transesterification process was optimized to achieve a conversion of 91.35% at 8.75 wt% catalyst loading, 63.2 °C, and 4.8 h(h) reaction time. A cradle-to-gate life cycle assessment (LCA) was performed according to ISO 14040/14044 with Ecoinvent 3.11 APOS system model integrated in OpenLCA 2.5 and the ReCiPe 2016 (H) method for 18 midpoint impact categories. The major environmental hotspots were associated with electricity and solvent consumptions for catalyst sulfonation, oil extraction, and esterification. The measured climate change potential for 17 experimental runs was in the range of 15.40 kg CO₂-eq (minimum impact) to 84.75 kg CO₂-eq (maximum impact), while terrestrial acidification was in the range of 0.129 kg SO₂-eq to 0.239 kg SO₂-eq. In the optimised condition, 15.70 kg CO₂-eq and 0.1306 kg SO₂-eq were obtained, which showed that a proper balance exists between high conversion and low environmental burden, thus confirming the use of corn cob derived acid catalysts for sustainable biodiesel production towards the circular bioeconomy.