DISSOLVING DISCARDED ELECTRONICS IN WATER

The electronics in every outdated smartphone, discarded computer, or broken-down toaster oven are a hodgepodge of pollution and toxins: cadmium, lead, mercury, polyvinyl chloride, and others.  
Recycling electronics can be a laborious process of breaking open the cases, often by hand, and then melting components or using harsh chemicals to reclaim the valuable minerals and rare earth metals inside. 
The problem is especially acute with smart watches and other small devices, which often aren’t worth the trouble to open up and scoop out the little bit of recyclable metals and components they contain.
Engineers at China’s Tianjin University have offered a solution: they made a smartwatch that dissolves in water.
The scientists devised a zinc-based compound laced with silver nanowires to connect resistors and other electronic components inside the watch.
They then embedded the circuitry inside a case made of a polymer that slowly dissolves in water.  
The wearable watch resisted sweat and rain, but both the case and the circuitry dissolved in about 40 hours when submerged in water.
What remained was the screen and individual electronic components, such as resistors or capacitors,  that could be reclaimed and potentially re-used.
If applied in a large-scale operation, reclaiming dissolved metals from the water could be practical as well.
TRENDPOST: Using the same process to build larger devices, from tablets to refrigerators, would not only create new sectors in the electronics and recycling industries but also ease a looming dilemma: face a relentlessly growing mountain of electronic waste or pay a messy environmental price for conventionally recycling it.