Scientists Discover Banana Peels Can Produce Environmentally Friendly Biomass

JAKARTA - A banana peel that is stung by a powerful light can be instantly converted into renewable energy, scientists have discovered.

New methods for extracting hydrogen, also possible with corn cobs, coffee beans and coconut shells, could be a significant way to increase gas supply from biomass.

It comes as Europe ramps up its hydrogen economy on the road, towards carbon neutrality by 2050.

According to the EU's hydrogen policy, 'renewable' hydrogen can be made from biomass (plant and animal materials), provided certain sustainability criteria are met.

One of the main concerns is that biomass can actually release more CO2, for example where forests are cleared, to fuel power plants.

However, a team of scientists based in Switzerland explained that all the products of their photo-thermal technique (light and heat based) are captureable, making it economical and climate safe.

"The relevance of our work is further heightened by the fact that we indirectly capture CO2 stores from the atmosphere over many years," wrote Dr Bhawna Nagar, co-author of the cole polytechnique fédérale de Lausanne (EPFL), citing Euronews Feb. 1.

"We have turned it into a useful end product in no time using a xenon flash."

What are the benefits of converting bananas and other biomass in this way? There are currently two main routes of chemical conversion of biomass using heat: gasification and pyrolysis.

Gasification blasts organic matter to a temperature of 1000 degrees Celsius, turning it into syngas, a mixture of hydrogen, methane, carbon monoxide, carbon dioxide, which is used as a biofuel. A solid carbon residue, known as 'biochar' or charcoal, is left behind.

Meanwhile, pyrolysis decomposes biomass at a lower temperature of 400-800 degrees Celsius, in a container without oxygen. However, this requires a very specific reactor that can handle high temperatures and pressures, scientists explain in Chemistry.

A simpler method is now available in the form of photo-prylosis, using a xenon lamp, which emits a bright white light, as has been seen in photographers' studios. One powerful flashlight can trigger biomass conversion in just a few milliseconds.

First, the banana peel must be dried at a temperature of about 100 degrees C for 24 hours, then ground and sieved to a fine powder, before being put into a stainless steel reactor.

"Each kilogram of dry biomass can produce about 100 liters of hydrogen and 330g of biochar, which means up to 33 percent of the weight of real dry banana peels," said Dr. Nagar.

To note, the separation of natural biomass into gas and charcoal is offered as a “smart, fast and environmentally friendly” solution for hydrogen production. Charcoal is also valuable because it can be added to soil to improve plant health, or stored as a carbon capture strategy.

Next, the scientists hope their method can be scaled up, and applied to industrial waste such as tires. It could even pave the way for solar photo-pyrolysis, making solar energy more sustainable.