Waste Product has Potential to Clean Waterways
Old tyres clogging up New Zealand's landfills could be recycled and used to clean up waterways, according to a
researcher at The University of Auckland.
Dr Nadhem Hamadi, who graduated this year with a PhD from the Faculty of Engineering, has spent the last four years
researching the use of tyres to create an adsorbent material that removes common wastewater contaminants such as
pesticides, chromium and colour.
"There are companies in the United States using tyres to create gas and liquids, but no one has been using the solid
waste. When I started my research I wanted to do something related to the environment, and I soon realised that old
tyres offered a raft of possibilities," he says.
Dr Hamadi found that tyre-derived activated carbon is produced by pyrolysis and activating the tyres. Activated carbon
commonly used to remove contaminants from water.
"The carbon we produced has similar properties to commercial varieties on the market and could therefore be economically
competitive", he says.
"But the real advantage of this form of activated carbon is that it is obtained from a waste material. Usually coal,
coconut shell and wood are used to create activated carbon so this project eliminates the need to deplete those natural
resources," he says.
"Scrap tyres are a growing problem around the world and the most common forms of disposal are land filling, followed by
stockpiling and incineration. This means we may have a new, environmentally-friendly method of recycling the tyres."
Dr Hamadi says the study was the first of its kind to convert old tyres into activated carbon, but the breakthrough has
been to come up with a product that is commercially competitive.
"To convince people that this process is worth it, we needed to trial it against commercial products, and we believe our
product is as good, if not better than those already available," he says.
The profitability of using old tyres to produce activated carbon is expected to increase further as the cost of other
forms of tyre disposal increases.
Dr Hamadi says the project is the first step towards creating the new product and he hopes a New Zealand company will
see the potential and commercialise the process.
"When I started my studies I wanted to do something useful for New Zealand and I hope this leads to an environmental
solution," he says.
Dr Hamadi, who is from Basra in Iraq, completed a Bachelor of Engineering in Kuwait and a Master of Engineering in Iraq
before immigrating to New Zealand in 1996.
Dr Hamadi conducted his research in the Department of Chemical and Materials Engineering and was supervised by Professor
Xiao Dong Chen and Associate Professor Mohammed Farid.