An assistant professor at the Nanyang Technological University (NTU) has devised a way to use fruit waste to synthesise MXenes, a conductive material that can be used to purify water efficiently via evaporation with the heat energy that's converted from sunlight.
While MXenes is not a new material, this is the first time fruit peels are being used to synthesise MXenes.
If commercialised, it can potentially reduce a significant portion of food waste and benefit places where electricity access is limited such as disaster zones or rural areas.
"What people see as a waste we see as a source of wealth," Ang said.
Giving fruit peels a second life
Edison Ang started this project after knowing how much food waste goes into our landfill each year.
"It has been reported at around 20,000 tonnes of food waste is generated in Singapore every year," he said. "And it is equivalent to around 8,000 Olympic sizes of a swimming pool."
The fruit juice industry contributes a significant amount of food waste, as only 50 per cent of the fruits are being used while another 50 per cent such as fruit peels are being thrown away, Ang understood.
Ang said this inspired him to do something to tackle this issue-- why not make something out of this waste instead of letting them go into our landfill?
"We can actually use them (fruit waste) and convert them into value-added products such as MXenes in this case," he said.
Currently, Ang has tried using coconut husk, orange peel and banana peel to create MXenes.
In fact, any organic materials, including plastic, paper, and also textile waste such as clothing can be used to make MXenes by mixing them with metal elements, Ang added.
From fruits to MXenes
So how are fruits turned into MXenes?
Fruit waste conversion process to MXenes.
Firstly, fruit waste is heated to turn into carbon.
Illustration of food waste.
Carbonised fruit peels.
MXenes are created when carbonised fruit peels are mixed with some metal element.
MXenes made from fruit peels.
Ang setting up his solar still.
MXenes have a property that allows for efficient light-to-heat conversion.
Such a property allows MXenes to be used in solar stills to distil dirty water using sunlight, which is a form of renewable energy.
The distilled water obtained from this process met PUB's drinking standards, according to Ang.
Challenges
The entire process, from conceptualisation to execution, took one and a half years to complete.
When asked about challenges faced in the project, Marliyana Binte Aizudin, a PhD student assisting Ang with this project, said that it took some time to find the right temperature to convert fruit waste to carbon with a 100 per cent success rate.
Marliyana assisting Ang with his research.
Identifying suitable renewable materials to construct the solar still is also a challenge.
Looking to work with companies
Besides upcycling food waste, Ang hopes this new way of producing MXenes can reduce the need to mine for raw materials to synthesise MXenes.
Ang is looking to partner with interested companies to scale up and commercialise this method of producing MXenes.
In fact, after knowing about his work, some hospitals or companies in the medical industry have approached him, Ang said.
These organisations admitted that a lot of disposable plastic items, such as gloves and tubes, were generated and they hope to find a way to put them into good use instead of throwing them away.
"Be part of the solution and not part of the pollution," Ang encouraged, as he continues to look into other types of waste that can be upcycled.
All images by Keyla Supharta unless otherwise stated.