Rice Husk Ash as Heterogeneous Silica-Based Catalyst Support for Palm
Fatty Acid Distillate Conversion to Biodiesel
Abstract
Rice husk ash (RHA) has potential as low-cost catalyst support to
produce biodiesel. In this study, RHA was used as precursor for
heterogeneous silica-based catalyst, Huskcatacid and Huskcatbase for
biodiesel production from palm fatty acid distillate (PFAD). The
formation of biodiesel from PFAD was performed via esterification using
Huskcatacid, followed by transesterification using Huskcatbase. The
biodiesel produced was evaluated based on several reaction parameters
such as oil to methanol ratio, amount of catalyst, reaction times and
temperature and the optimization of parameters was carried out. Results
showed that Huskcatacid was efficiently employed in esterification of
PFAD to afford 91.6% ester in 1:1 (PFAD:MeOH) and 5 wt% catalyst,
followed by transesterification in 1:1 (oil: MeOH) using Huskcatbase (1
wt%) to produce 99.73% biodiesel in 30 min with high percentage of
methyl palmitate (34.43%) and methyl oleate (57.86%). Both Huskcatacid
and Huskcatbase have high porosity (2.726 x 10-3 cm3/g and 4.985 x 10-3
cm3/g) and surface area (7.362 m2/g and 14.493 m2/g), respectively,
which offer efficient esterification and easy glycerol separation. The
biodiesel obtained was applied on Megatech®-Mark III engine and
demonstrated a proportional increased of torque (ɽ) with the B100
biodiesel loading. Rice husk demonstrated a good potential as solid
support heterogeneous catalysts and feedstock for value-added products,
which also assists to overcome agricultural waste management issues.