Not all plastics are equal — some types and colors are easier to recycle than others.
Not all plastics are equal — some types and colors are easier to recycle than others. For instance, black foam and black coffee lids, which are often made of polystyrene, usually end up in landfills because color additives lead to ineffective sorting. Now, researchers report in ACS Central Science the ability to leverage one additive in black plastics, with the help of sunlight or white LEDs, to convert black and colored polystyrene waste into reusable starting materials.
“Simple, visible light irradiation holds the potential to transform the chemical recycling of plastics, using the additives already found in many commercial products,” say the paper’s authors, Sewon Oh, Hanning Jiang and Erin Stache.
An emerging strategy for plastic recycling involves using light to help break down plastic into chemically useful materials that can be recycled into new products. This process requires a helper compound to convert light into the heat needed to break apart polymer bonds. However, finding the right helper that won’t create more waste and is easily incorporated into recycled materials remains a challenge for researchers. Seeking to create a circular economy for plastic recycling, Stache and a team of researchers took advantage of something already found in black polystyrene waste — an additive known as carbon black.
Read more at American Chemical Society
Image: Inside this reaction vial, spotlit by concentrated sunlight, a piece of black polystyrene from a foam tray breaks down into a recyclable material. (Credit: Hanning Jiang)
