WASTE & RECYCLING

Microrecycling science delivers new ‘material microsurgery’ technique

A new technology that promises to enhance the advanced manufacturing sector in Australia has been developed by the pioneers of ‘microrecycling science’ at UNSW’s Centre for Sustainable Materials Research and Technology (SMaRT).

The novel ‘material microsurgery’ technique developed by Professor Veena Sahajwalla and her team at SMaRT can extract valuable materials and elements from complex waste items and reform them into strengthening layers for steel and other applications. The technique is the latest breakthrough by Sahajwalla’s team as they seek to develop new ways to address society’s growing waste and recycling challenges with innovations that can boost manufacturing capability, creating jobs and prosperity while enhancing environmental and social outcomes. The SMaRT Centre created the phrase ‘mircorecycling science’ to describe its novel approach to researching innovative approaches and technologies to reform various waste streams into value added materials and products. “Australia’s governments have agreed to ban the exporting of glass, plastic, paper and rubber tyres from January 2021,” Sahajwalla explains. “Therefore we need to start treating these waste items as the ‘renewable resources’ they really area. Ever-increasing population, technological advancement, variable consumption trends, and lack of efficiency in using materials are forcing us near a crisis point in terms of waste management. “And since COVID-19 has disrupted global supply chains, Australia’s manufacturing has come under sharp focus. The problem of countries now being affected by unreliable global supply chains for certain materials and goods has sparked questions around how to produce the goods they need.” Sahajwalla’s team is developing new technologies that don’t just reform complex waste items into new, value-added materials to help address this ‘sovereign capability’ issue, but do so through decentralised manufacturing. “A key challenge is that existing, centralised recycling and waste treatment methods at scale often just turn things like PET bottles back into PET bottles,” Sahajwalla adds. “What we need is a recycling and manufacturing system that can innovate to reform waste for more diverse and value-added end uses. “Recyclers traditionally haven’t seen themselves as manufacturers and manufacturers haven’t seen themselves as recyclers, but we need them to. So, if we accept that we need plastic and want to keep it out of landfill, we need a system that treats it as a renewable resource.” Green materials and products ‘Material microsurgery’ is the latest innovative technique from the SMaRT Centre, which has pioneered the technological concept of Microfactories to reform different waste streams that mostly end up in landfill or stockpiles by turning them into value added ‘green materials and products’, thus able to revolutionise the recycling and manufacturing sectors. Material microsurgery uses the ‘foundational selective thermal transformation’ techniques developed in the microrecycling science by the SMaRT Centre to extract valuable core elements from electronic waste. This can be used in a novel way as a highperformance hybrid layer to improve performance of the surface of steel, meaning that regular steel can be enhanced to have a ‘super surface’ via the modification. This method could be a suitable alternative to conventional surface coatings and reduce the burden on raw material feedstocks. In the material microsurgery study, glass and plastic from discarded

Professor Veena Sahajwalla in a section of the Microfactorie at UNSW’s Centre for Sustainable Materials Research and Technology (SMaRT).

computer monitors and copper from printed circuit boards were used to produce a hybrid thin film layer on a steel substrate to provide a protective layer over the base material at the microscale to alter the overall performance of the material. This high-performance advanced material is a hybrid layer chemically bonded in situ on steel to produce a super surface with enhanced mechanical properties compared to the uncoated steel. Material microsurgery “We use the term ‘material microsurgery’ because we were inspired by the processes medical surgeons use in microsurgery where they apply targeted and selective solutions to problems,” says Sahajwalla. “Existing waste and recycling technology doesn’t do this for our traditional waste treatments. We need to step up to do the things that were thought unimaginable for waste management so it can be cutting edge.” Sahajwalla and her team’s Microfactorie technologies use various discrete modules to transform problematic waste materials, such as glass, textiles and plastics, into new value-added materials and products such as engineered green ceramics for the built environment, or plastic filament as a ‘renewable resource’ for 3D printing. This modular technology is capable of harnessing value from waste resources to deliver high-value materials and products. The SMaRT Centre now houses various Microfactories and the material microsurgery technique is the latest innovation that holds promise to help treat waste as a ‘renewable resource’ to produce green materials and products that otherwise require virgin resources. “COVID has unearthed the weaknesses in our current way forward to meet these challenges,” says Sahajwalla. “But we can start a whole new ‘green materials’ movement where we use waste as renewable resources for decentralised manufacturing to supercharge our economy.”

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