Waste cigarette butts could be incorporated into pavements
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Research from the Royal Melbourne Institute of Technology (RMIT) University in Melbourne, Australia, has demonstrated that mixing cigarette butts with asphalt concrete can produce a useful insulator capable of handling heavy traffic.
Every year, trillions of cigarette butts are produced - approximately 1.2 million tonnes. Due to population growth and other factors, this volume of waste could grow by 50 per cent by 2025.
Most of this waste is discarded into the environment. During the very long process of degradation, toxic chemicals trapped in the filters - such as arsenic, chromium, nickel and cadmium - leak into the soil, rivers and the ocean.
Researchers from RMIT University believe that this mass of waste cigarette butts could be put to good use. A recent study has demonstrated that mixing cigarette butts with asphalt concrete can produce a composite material capable of handling heavy traffic and reducing thermal conductivity.
“I have been trying for many years to find sustainable and practical methods for solving the problem of cigarette butt pollution,” said Dr Abbas Mohajerani, a senior RMIT lecturer who led the study. Dr Mohajerani’s previous work has involved recycling cigarette butts by incorporating them into one per cent cigarette bricks. These required as little as half as much energy or less to be fired and had better insulating properties.
“In this research, we encapsulated the cigarette butts with bitumen and paraffin wax to lock in the chemicals and prevent any leaching from the asphalt concrete,” he said. “The encapsulated cigarette butts were mixed with hot asphalt mix for making samples”.
By encapsulating the cigarettes, Dr Mohajerani was able to restrict the interaction of cigarette butts with fluids, preventing the leakage of hundreds of toxic chemicals. The encapsulated butts, combined with asphalt, could have various applications, such as in pavement construction.
This recycling has the potential not just to reduce the problem of cigarette waste, but could also be useful in reducing the urban heat island effect: the phenomenon of cities and other urban areas being warmed than surrounding areas due to greater density of humans and human activity.
“This research shows that you can create a new construction material while ridding the environment of a huge waste problem,” Dr Mohajerani said.