PHYSICOCHEMICAL CHARACTERIZATION OF OKRA AND POTATO WASTES FOR THE PRODUCTION OF BIOCRUDE OIL

Abstract

Asignificant amount of agricultural and food waste is not properly or optimally utilized
to produce value-added materials; instead, some are simply incinerated, contributing to
environmental pollution challenges. Effective utilization of agricultural waste for producing valueadded requires thorough feedstock characterization. In light of this, the present study focused on
the characterization of okra and sweet potato wastes to evaluate their suitability as feedstocks for
biocrude oil production via hydrothermal liquefaction (HTL). The characterization analyses
conducted include proximate and ultimate analyses, thermogravimetric analysis (TGA), and Fourier
transform infrared (FTIR) spectroscopy. The proximate analysis revealed that sweet potato waste
has a low ash content (9.0%) and a high fixed carbon content (60.66%), while okra waste also
showed a low ash content (9.67%) and an even higher fixed carbon content (66.00%). These low
ash and high fixed carbon values suggest that both feedstocks have strong potential for biocrude
oil production via HTL. Additionally, the ultimate analysis results for both wastes were found to be
encouraging. The TGA results indicated a nearly constant weight loss within the temperature range
of 450 °C–550 °C for both feedstocks, attributed to thermal degradation. The FTIR spectra further
confirmed the presence of functional groups such as O–H, C=C, C≡C, C–C, and C–O at various
stretching bands. The presence of C=C and other functional groups suggests the likely presence of
organic compounds and chemicals in the feedstocks. In conclusion, the characterization results
demonstrate that okra and sweet potato wastes are promising feedstocks for the production of
biocrude oil and other valuable chemicals through the hydrothermal liquefaction process.