Process Optimization, Environmental and Economic Assessment of TiO₂ Nanocatalyst-assisted Gmelina-Mucuna Oil-blends
J. Environ. Nanotechnol., Volume 15, No 2 (June 2026) pp. 16-30
Abstract
This study investigated the production, optimization, environmental performance, and techno-economic viability of biodiesel derived from a novel non-edible blended feedstock of Gmelina arborea and Mucuna pruriens oils using a TiO₂ nanocatalyst. Transesterification was optimized using Response Surface Methodology under a Central Composite Design, considering catalyst concentration, methanol-to-oil ratio (MOR), temperature, reaction time, and agitation speed as process variables. An optimal biodiesel yield of 96% was achieved at 1.2 wt% catalyst loading, 8:1 MOR, 55^O C, 500 rpm agitation, and 70 minutes reaction time. The produced Gmelina-Mucuna oil meets key ASTM quality standards. Kinematic viscosity (ASTM D445), acid value (ASTM D664), and flash point (ASTM D93) were within acceptable limits. The measured density of oil was 0.946 g/mL, consistent with ASTM D1298 reference ranges for vegetable oils. Engine emission analysis of biodiesel-diesel blends (B10-B100) showed substantial reductions in carbon monoxide (35-45%) and lower smoke opacity compared to conventional diesel. Slight increases in CO emissions for some blends were observed. However, the biodiesel blends indicated improved oxidation and more complete combustion due to the oxygenated structure of biodiesel. Techno-economic evaluation revealed an adjusted laboratory production cost of approximately ₦400/L after methanol recovery and removal of non-recurring expenses. At industrial scale, total production cost (CAPEX + OPEX) decreased from ₦980.5/L at 0.5 million L/year to ₦695.9/L at 7 million L/year, demonstrating strong economies of scale. Overall, TiO₂-catalyzed Gmelina-Mucuna biodiesel is technically feasible, environmentally beneficial, and economically promising.
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