{"id":139603,"date":"2024-02-28T07:20:00","date_gmt":"2024-02-28T06:20:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=139603"},"modified":"2024-02-23T10:49:01","modified_gmt":"2024-02-23T09:49:01","slug":"food-based-aerogel-recovers-gold-from-e-waste","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/food-based-aerogel-recovers-gold-from-e-waste\/","title":{"rendered":"Food-based aerogel recovers gold from e-waste"},"content":{"rendered":"\n\n\n

Adsorption\u2014not alchemy\u2014can transform waste into\u00a0recycled gold<\/a>. A protein sponge made from food waste recovers gold from e-waste, creating high-purity nuggets (Adv. Mater.<\/em>\u00a02024, DOI:\u00a010.1002\/adma.202310642<\/a>).<\/p>\n\n\n

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\"Burning
Burning the aerogel that had adsorbed and reduced gold from an e-waste solution produced this 0.5 g gold nugget with a purity of around 91%, corresponding to 21 to 22 karats.\u00a0<\/strong>Credit: Peydayesh et al.\/Adv. Mater.<\/em>\u00a02024<\/figcaption><\/figure><\/div>\n\n\n

\u201cThis study is an excellent example of developing sustainable and environment friendly materials technologies,\u201d writes Mustafa O. Guler<\/a>, a biomaterials scientist at the University of Chicago who wasn\u2019t part of the work, in an email. \u201cBy exploring innovative food waste materials for sustainability solutions, the researchers have successfully developed a new method for recycling valuable metals.\u201d<\/p>\n\n\n\n

Raffaele Mezzenga<\/a>, a materials scientist and physicist at the Swiss Federal Institute of Technology (ETH), Zurich, and colleagues started with whey protein, a byproduct of the cheesemaking industry, and made a low-density aerogel. Making the spongelike material is cheap, he says. \u201cThe value of the gold we recover is 50 times the value we invest to transform the protein into this sponge.\u201d<\/p>\n\n\n

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Credit: Peydayesh et al.\/Adv. Mater.<\/em>\u00a02024\u00a0<\/figcaption><\/figure><\/div>\n\n\n

When put dunked in an e-waste solution, this light, squishy sponge made of whey protein quickly saturates with gold before it can adsorb other metals in an e-waste solution. Thanks to its selectivity for gold, and its porosity and surface area, the material is a better adsorbent for gold than activated carbon. <\/p>\n\n\n\n

The researchers placed whey protein into an acidic solution and heated it, which unraveled the proteins from tiny balls into strands. Then they freeze-dried the solution, forming a lightweight puck with high porosity. \u201cYou can place them on the top of a flower. And the advantage of having aerogels is that they have high surface area,\u201d says Mohammad Peydayesh<\/a>, a chemical engineer who\u2019s also part of the research team at ETH Zurich.<\/p>\n\n\n\n

The researchers tested the gel\u2019s ability to adsorb gold from a solution also containing other metals\u2014including copper, lead, and nickel\u2014at the same concentration. The aerogel sucked up 93% of the gold while removing less than 10% of any of the other metals. To test the protein sponge with real e-waste, the team dissolved computer motherboards in aqua regia, a mix of nitric acid and hydrochloric acid. Gold ions from the mixture settled on the surface of the aerogel and were reduced, forming metallic gold. Each gram of aerogel snatched 190 mg of gold. Burning the aerogel freed the gold, turning it into a tiny hunk of metal.<\/p>\n\n\n\n

\u201cIt was really exciting to find this nugget in the ashes,\u201d Peydayesh recalls. The nugget was about 91% gold, which corresponds to about 21 to 22 karats.<\/p>\n\n\n\n

Because of its exceptional porosity, surface area, and high density of chemical functional groups, the aerogel exhibits a \u201cremarkable ability\u201d to quickly adsorb gold ions with a high capacity and selectivity, writes Peng Yang<\/a>, a polymer chemist and materials scientist at Shaanxi Normal University who wasn\u2019t part of the study, by email. Further study may reveal improvements in the method used to make the gel or identify ways to recover the gold without destroying the sponge to make the process more cost-effective, Yang says.<\/p>\n\n\n\n

The method already presents an improvement over activated carbon, a more typical adsorption method used to recover gold. Each gram of activated carbon only adsorbed about 60 mg of gold from an e-waste mixture, the team found. Because it takes a lot of energy to create activated carbon, recovering the same amount of gold using activated carbon had a higher environmental impact in a life cycle analysis.<\/p>\n\n\n\n

The team is already eyeing other food waste proteins, such as keratin and those from the production of tofu, that could potentially help with other needs, such as the recycling of rare earth metals<\/a>. \u201cWe can simultaneously address the global waste of food and e-waste to produce something really precious,\u201d Peydayesh says.<\/p>\n","protected":false},"excerpt":{"rendered":"

Adsorption\u2014not alchemy\u2014can transform waste into\u00a0recycled gold. A protein sponge made from food waste recovers gold from e-waste, creating high-purity nuggets (Adv. Mater.\u00a02024, DOI:\u00a010.1002\/adma.202310642). \u201cThis study is an excellent example of developing sustainable and environment friendly materials technologies,\u201d writes Mustafa O. Guler, a biomaterials scientist at the University of Chicago who wasn\u2019t part of the work, in […]<\/p>\n","protected":false},"author":59,"featured_media":139635,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","nova_meta_subtitle":"The protein sponge sucks up three times as much gold per gram as a typical activated carbon adsorbent ","footnotes":""},"categories":[5572,17143],"tags":[21787,5838,10416,23669,18666,23670,12417,10453],"supplier":[277],"class_list":["post-139603","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bio-based","category-recycling","tag-aerogel","tag-bioeconomy","tag-circulareconomy","tag-extraction","tag-filter","tag-nanofibrils","tag-proteins","tag-recycling","supplier-eidgenoessische-technische-hochschule-zuerich-eth-zuerich"],"_links":{"self":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/139603","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/users\/59"}],"replies":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/comments?post=139603"}],"version-history":[{"count":0,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/posts\/139603\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media\/139635"}],"wp:attachment":[{"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/media?parent=139603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/categories?post=139603"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/tags?post=139603"},{"taxonomy":"supplier","embeddable":true,"href":"https:\/\/renewable-carbon.eu\/news\/wp-json\/wp\/v2\/supplier?post=139603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}