Biodiesel is seen as a non-fossil replacement for carbon dioxide-spewing diesel. On the flip side, biodiesel emits more nitrous oxide, is unstable when stored for long, does not always burn well, and is costly to make.
Scientists are searching for solutions to these problems. Quantum dated December 26, 2022, highlighted the discovery, by Prof Anand Krishnaswamy of IIT-Madras, of a surfactant that can emulsify karanja oil-based biodiesel.
Now, Dr J Jayaprabhakar et al find a way to process used cooking oil to derive biodiesel that burns better.
Jayaprabhakar, who teaches at Sathyabama Institute of Science and Technology, Chennai, and seven other researchers came up with a catalyst made of nanoparticles of zinc oxide and tungsto phosphoric acid (TPA) to convert used cooking oil into biodiesel. Usually hydroxides of potassium or sodium are used as catalysts.
Jayaprabhakar’s goal was “to synthesise biodiesel using solid acid catalysts at a low cost... without compromising yield.”
The catalysts were designed to improve their effectiveness, making production cost-effective. They mixed TPA and zinc oxide in the ratio 9:1 by weight.
They discovered an optimal set of parameters, through which 94 per cent of waste cooking oil could be converted to biodiesel.
Their conclusion: Biodiesel fuel technology laden with zinc oxide nanoparticles can cut compression injection’s reliance on fossil fuel.
You can cut nitrous oxide emissions, Jayaprabhakar says, but that will reduce efficiency. Instead, use catalytic converters to deal with nitrous oxide outside the combustion chamber, he says.