Abstract:
The total energy consumption is increased due to the rapid expansion of industries and
metropolitan development. Biodiesel is a substitute fuel to conventional diesel, which
is non-carcinogenic, sustainable, and has a high cetane number. The conventional
methods used for biodiesel synthesis are energy-intensive, and operational cost is high.
Catalytic esterification and transesterification methods are employ for the cleaner
production of biodiesel. Due to the presence of high content of free fatty acid (FFA),
transesterification carries the drawback of sponification.
In the esterification reaction, FFA was reduced using an acidic catalyst. However,
thermodynamic equilibrium restricts the overall conversion and slows the pace of the
reaction—the current study used microbubble-mediated mass transfer technology to
overcome this problem. Acid catalysts are used for esterification, show good activity,
and produce high-quality biodiesel. Although the rate of the reaction is slower, it takes
longer and at a higher temperature to achieve the maximal conversion. Various basic
catalysts have been used for biodiesel synthesis to overcome the acid catalysts'
drawbacks. Under mild conditions, show high catalytic activity in the transesterification
process. However, base catalysts are limited due to high water affinity and moisture
during storage. Saponification is another disadvantageous feature of these catalysts.
Esterification and transesterification could both be performed by a catalyst that has both
acidic and basic sites. This study aims to propose a sustainable strategy to energy
generation using microbubble technology and bi-functional catalyst. As a
heterogeneous catalyst for the generation of biodiesel, strontium zirconium oxide (7%
Sr/ZrO2) was produced, and compared with naturally occurring bi-functional catalysts
such as zwitterions is also used to investigate biodiesel production. To optimize the
synthetic bifunctional catalyst response surface methodology (RSM) was used.
