Abstract
This research explores the utilization of carbide slag from welder’s waste as a crucial source of
CaO for the development of a bi-functional heterogeneous catalyst, incorporating welder’s waste
and pig bones, in the simultaneous esterification and transesterification of Rubber seed oil for
biodiesel production. Comprehensive characterization of the catalyst and its precursors assessed
their structural, compositional, morphological, and thermal attributes. Employing a one-step
transesterification method with response surface methodology (RSM) optimization, the bifunctional
catalyst
demonstrated
bi-functionality,
featuring
a
substantial
surface
area
(393
m
2
/g)
and pore volume (0.203 cm
3
/g). This catalyst facilitated a maximum biodiesel yield of 92.6%,
achieved under optimized conditions: a reaction temperature of 60 °C, catalyst loading of 1
wt.%, reaction time of 75 minutes, and a methanol-to-oil ratio of 6:1. The RSM model exhibited
high adequacy (R2 = 0.9577), and the biodiesel produced adhered to established standards. The
synthesized catalyst presents advantages, including reusability, straightforward synthesis,
stability, substantial surface area, and accessibility of precursor materials, positioning it as a
promising alternative to conventional catalysts.