UNW project seeks to address e-waste

Electronic waste encapsulates computers, mobile phones, household appliances and medical waste which is stored and/or thrown away in unsafe conditions.

Imagine if you drop your phone in water, for instance, or your fridge finds itself on the brink. These are the kinds of devices that are thrown away and the electronic components in them become e-waste.

Statistics from the UN report are troubling: the 62 million tonnes of e-waste generated in 2022 would fill 1.55 million 40-tonne trucks. Less than one quarter (22.3%) was documented as having been properly collected and recycled in 2022. E-waste is on track to reach 82 million tonnes by 2030. E-waste is frequently dumped in landfill or burned.

The precious metals that make up electronic components - such as iron, aluminium, copper and nickel - are often not recovered. Besides environmental impacts, individuals handling hazardous e-waste face significant risks. Some melt electronic components to extract these valuable materials and in doing so, are exposed to toxic materials.

A number of challenges face recycling electronic waste. This includes technological progress, higher consumption, shorter product life cycles, and inadequate e-waste management infrastructure. A key finding from the UN report suggests that if countries worldwide can bring recycling rates to 60% by 2030, the benefits would exceed more than $38 billion.

One project run by researchers at the University of Washington is looking at the possibility of scaling up systems to recycle the printed circuit boards (PCBs) found in almost all electronic devices, and consequently recycle e-waste. 

The advantages of being able to do so would be numerous. Among others, PCBs are formulated from glass fibre, plastic and copper which are difficult to separate from one another and therefore unable to be recycled in most cases. 

“PCBs make up a pretty large fraction of the mass and volume of electronic waste,” explained co-senior author Vikram Iyer, a UW assistant professor in the Paul G. Allen School of Computer Science & Engineering. “They’re constructed to be fireproof and chemical-proof, which is great in terms of making them very robust. But that also makes them basically impossible to recycle. Here, we created a new material formulation that has the electrical properties comparable to conventional PCBs as well as a process to recycle them repeatedly.”

The project has overseen the development of a new PCB which can be recycled repeatedly without losing material. The chosen material is a solvent that turns a type of vitrimer into a “jelly-like substance” without damaging it, meaning solid components can be separated for recycling purposes.

The vitrimer jelly that comes out of that process can be turned into new PCBs - vitrimer printed circuit boards (vPCBs), creating a more circular approach which equals less material waste, costs and environmental impact.

“On a molecular level, polymers are kind of like spaghetti noodles, which wrap and get compacted,” said co-senior author Aniruddh Vashisth, a UW assistant professor in the mechanical engineering department. “But vitrimers are distinct because the molecules that make up each noodle can unlink and relink. It’s almost like each piece of spaghetti is made of small Legos.”

In analysing the environmental impact of such a process, the researchers reported that recycled vPCBs could result in a 48% reduction in global warming potential and an 81% reduction in carcinogenic emissions compared with traditional PCBs.