Char made from cigarette butts may help mitigate pollution in waterways
Environmentally hazardous cigarette butts may ironically hold the answer to cleansing Australia's waterways of major metal contaminants, according to a new James Cook University-led published in the journal Chemical Engineering Science.
JCU Lecturer in Mechanical Engineering Dr. Elsa Antunes and her team found that char created from thermally decomposing cigarette butts in an oxygen-free chamber removed about 53% of copper and 95% of nickel during lab trials with simulated wastewater.
The butts were provided by the anti-cigarette waste charity "No More Butts."
"Heavy metals are still a problem in our waterways and the consequences of heavy metals for humans and other living organisms are also very high," Dr. Antunes said.
"At the moment, you can use activated carbon, which is produced from coal, to remove heavy metal from our waterways, which is not an environmentally friendly product.
"But if we can create this circular economy where we can collect these cigarette butts, transform them into char and then use that to mitigate pollution, then that is much more sustainable."
Dr. Antunes said while a range of other materials such as wood and biosolids have previously been converted into biochar to target different contaminants in wastewater, they had now proven their effectiveness in removing heavy metals.
"Our results were very interesting and could be applied at an industrial scale," she said.
"The chemical composition of the char will have an impact in the removal of the contaminants, so when we are making char, we think about what contaminant we want to remove and then select the raw material best suited to that.
"But what we've also found is we are able to control the production conditions to obtain different porosities, or surface area, of the char, which can be used to target different contaminants."
Dr. Antunes' work with char has already shown promising results, having previously worked with Townsville City Council to remove phosphorous and nitrogen from waterways using char made from biosolids.
She said her team are now keen to test the cigarette-based char on different contaminants in order to gauge its effectiveness compared to other forms of char.
"One of my Masters students is working on removing pharmaceuticals from wastewater, so this could be another potential use," she said.
More information: Premchand Premchand et al, Sustainable valorisation of cigarette butts waste through pyrolysis: An insight into the pyrolytic products and subsequent aqueous heavy metals removal by pyrolytic char, Chemical Engineering Science (2024).
Provided by James Cook University