Advances in Materials Science and Engineering<\/a>.<\/p>\n\u201cWe\u2019re trying to track the fate of these chemicals in the recycling process and figure out how to effectively remove them,\u201d says Curtzwiler, an associate professor of food science and human nutrition.<\/p>\n
The study focused on polypropylene\u2014No. 5 plastic\u2014which is frequently used for dairy product tubs and other food packaging. Increased polypropylene recycling is a high-priority target for reducing plastic waste because it\u2019s a durable, high-value material with a low current rate of recycling, as little as 3% by some estimates.<\/p>\n
When investigating different ways of washing polypropylene, researchers noticed the samples\u2014which are ground into flakes 1 to 3 mm wide, roughly the size of coarse salt grains\u2014had reduced levels of some potentially toxic chemicals after being washed.<\/p>\n
\u201cWe thought, \u2018OK, these compounds have to be going somewhere.\u2019 We knew we needed to take a closer look at the water,\u201d Curtzwiler says.<\/p>\n
No detectable phthalates or bisphenols\u2014another hormone-disrupting class of plastic enhancers, such as BPA\u2014appeared in wash water when plastics were cleaned with physical agitation alone or agitation combined with sodium hydroxide, a form of lye. But when cleaning with ultrasonic vibration or sodium hydroxide plus a common industrial detergent, researchers found di(2-ethylhexyl) phthalate (DEHP) and di-cyclohexyl phthalate (DCHP) in the wash water.<\/p>\n
The sodium hydroxide and detergent method was tested using the same water over 15 cycles, as wash water is often reused in industrial settings. Researchers found the levels of DEHP accumulated over time, from 10 times the level prohibited in drinking water after the first wash to 25 times the drinking-water limit after 15 cycles. The concentration of the industrial detergent fell as wash water was reused, suggesting the plastic flakes were absorbing some of the cleaner \u2013 concerning because it can also disrupt hormonal systems.<\/p>\n
The study suggests that while further research is needed, recycling companies may need to change how plastic is cleaned and water involved is managed. The risks can be mitigated, says study coauthor Keith Vorst, director of the Polymer and Food Protection Consortium.<\/p>\n
\u201cIt\u2019s important to understand that these are solvable problems,\u201d says Vorst, an associate professor of food science and human nutrition.<\/p>\n
Foam fractionation\u2014passing air bubbles through water to skim off contaminants caught in the resulting foam\u2014is one option for filtering out some toxic chemicals. Iowa State researchers also are studying electro-oxidation (using electricity to break down concerning chemicals) and a bio-based treatment with a nanomaterial called carbon nano-onions, Curtzwiler says.<\/p>\n
Reducing how much water is used to wash recyclable plastic also could be part of a multi-pronged solution, whether through improved sorting or cleaning methods that involve far less or even no water, Vorst says.<\/p>\n
Changes must be economical in an industry trying to expand while operating on thin margins, Curtzwiler says. The US Environmental Protection Agency has set a goal to boost the national plastic recycling rate to 50% by 2030, but the most recent report by The Recycling Partnership estimated that only 21% of all eligible household material in the US is recycled, with rates even lower for plastic.<\/p>\n
\u201cYou don\u2019t want the cure to be worse than the disease, but we need to do this as cost effectively as possible,\u201d he says.<\/p>\n
Funding for this work came, in part, from the Institute for the Advancement of Food and Nutrition Sciences.<\/p>\n
Source: Iowa State University<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"Share this Article You are free to share this article under the Attribution 4.0 International license. Recycling plants\u2019…\n","protected":false},"author":2,"featured_media":410420,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[103,61,60,33758,3751,2709],"class_list":["post-410419","post","type-post","status-publish","format-standard","has-post-thumbnail","category-health","tag-health","tag-ie","tag-ireland","tag-plastics","tag-recycling","tag-water"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/410419","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=410419"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/410419\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/410420"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=410419"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=410419"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=410419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}