A team of researchers from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley have developed a potential solution to e-waste: a fully recyclable and biodegradable printed circuit. The researchers say that the advance could divert wearable devices and other flexible electronics from landfill, and mitigate the health and environmental hazards posed by heavy metal waste.
“When it comes to plastic e-waste, it’s easy to say it’s impossible to solve and walk away,” said senior author Ting Xu, a faculty senior scientist in Berkeley Lab’s Materials Sciences Division, and professor of chemistry and materials science and engineering at UC Berkeley. “But scientists are finding more evidence of significant health and environmental concerns caused by e-waste leaching into the soil and groundwater. With this study, we’re showing that even though you can’t solve the whole problem yet, you can at least tackle the problem of recovering heavy metals without polluting the environment.”
In a previous study, Xu and her team demonstrated a biodegradable plastic material embedded with purified enzymes such as Burkholderia cepacian lipase (BC-lipase). Through that work, they discovered that hot water activates BC-lipase, prompting the enzyme to degrade polymer chains into monomer building blocks. They also learned that BC-lipase is a finicky “eater.” Before a lipase can convert a polymer chain into monomers, it must first catch the end of a polymer chain. By controlling when the lipase finds the chain end, it is possible to ensure the materials don’t degrade until the water reaches a certain temperature.
For the current study, Xu and her team simplified the process even further. Instead of expensive purified enzymes, the biodegradable printed circuits rely on cheaper, shelf-ready BC lipase “cocktails.” This significantly reduces costs, facilitating the printed circuit’s entry into mass manufacturing, Xu said.