KI-impregnated oyster shell as a solid catalyst for soybean oil transesterification.

Research on inexpensive and green catalysts is needed for economical production of biodiesel. The goal of the research was to test KI-impregnated calcined oyster shell as a solid catalyst for transesterification of soybean oil. Specific objectives were to characterize KI-impregnated oyster shell, determine the effect of reaction variables and reaction kinetics. The catalyst was synthesized by impregnating KI on calcined oyster shells. X-ray diffraction analysis indicated the presence of portlandite and potassium iodide on the surface and a 31-fold increase in surface as a result of calcination and KI impregnation. Under the conditions tested, ideal reaction variables were 1 mmol g(-1) for catalyst loading, 50 °C for temperature, 10:1 for methanol/oil, and 4h for reaction time. The transesterification followed a first-order reaction (k=0.4385 h(-1)). The option of using oyster shell for the production of transesterification catalysts could have economic benefits to the aquaculture industry in the US.