Biodiesel production
from castor oil seeds cultivated in constructed wetlands
Sathya R. and Das Ashutosh
Res. J. Chem. Environ.; Vol. 30(1); 140-153;
doi: https://doi.org/10.25303/301rjce1400153; (2026)
Abstract
With the escalating demand for renewable energy and the imperative to mitigate environmental
degradation, there is increasing interest in biodiesel as a sustainable substitute
of fossil fuels. The present study presents a comparative evaluation of biodiesel
production from castor seeds cultivated in two distinct environments: conventional
agricultural fields and rice mill effluent-fed constructed wetlands. Castor (Ricinus
communis L.), a non-edible oilseed crop known for its resilience and high oil content,
was assessed for seed quality, oil yield, trans esterification efficiency, fuel
properties and kinetic and thermodynamic parameters. Wetland-grown seeds, found
to be with marginally poorer yield (82%) and quality, demonstrated significant potential
for biodiesel production while simultaneously contributing to wastewater remediation.
Kinetic modelling confirmed pseudo-first-order reaction behaviour, with agricultural
oil exhibiting a higher rate constant (0.0034 min⁻¹) than wetland oil (0.0025 min⁻¹).
Agricultural seeds, on the other hand, yielded superior oil content (50%) and biodiesel
conversion (94%), with favourable physicochemical properties such as lower acid
value, enhanced cold flow and higher flash point. Thermodynamic analysis revealed
higher activation energy and enthalpy for agricultural oil, indicating more efficient
conversion. The dual functionality of constructed wetlands, biomass generation and
effluent treatment, positions them as a viable strategy for circular economy integration.
