AF aerogel
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An AF aerogel is an aerogel that has been developed using amyloid fibrils derived from whey, as an adsorbent for gold recovery from e-waste.[1][2] Other earlier AF aerogels have been developed that use synthetic aramid fibers, in particular for thermal insulation.[3] A study has demonstrated that protein derived AF aerogels have a high capacity for gold adsorption. Their use would have a less environmental impact than that of the conventional use of activated carbon as adsorbent.[1]
Process
[edit]
Nanofibrils of protein amyloid derived from whey is a novel (as of 2023) adsorbent for the extraction of gold from electronic waste. Materials scientists at the Swiss Federal Institute of Technology developed the method.[2] Prepared AF aerogels have a very high capacity for the adsorption of gold. [1]
The process begins with the separation of amyloid fibrils from waste dairy products, and their incorporation into an aerogel. The AF aerogel is then used in a solvent of dissolved computer motherboards (the main printed circuit board in a computer) to extract the gold contained. Af aerogels can convert gold (Au) ions into single crystalline flakes. The result is a yield of high purity gold nuggets, equating to around 21-22 carats, with only trace amounts of other metals present.[1]
Economics
[edit]The use of AF aerogels has a profitable profile. It costs just over one dollar to retrieve one gram of gold, and the market value of a gram of gold (as of 2023) is around 50 dollars.[1]
Environment
[edit]One ton of e-waste generates more than a hundred times more gold than a ton of gold ore. In a report by the UN to address the increasing issue of e-waste one of the solutions put forward was the use of urban mining, to extract metals and minerals from e-waste.[4]
The use of AF aerogels compares favourably in terms of environmental impact in comparison to the conventional use of activated carbon adsorbents.[1]
References
[edit]- ^ a b c d e f Peydayesh, M; Boschi, E; Donat, F; Mezzenga, R (May 2024). "Gold Recovery from E-Waste by Food-Waste Amyloid Aerogels". Advanced Materials. 36 (19): e2310642. Bibcode:2024AdM....3610642P. doi:10.1002/adma.202310642. hdl:20.500.11850/658267. PMID 38262611.
- ^ a b Carolyn Wilke, Special To c&En (19 February 2024). "Whey protein aerogel captures e-waste gold". C&EN Global Enterprise. 102 (5): 7. doi:10.1021/cen-10205-scicon1.
- ^ Li, Zhi; Cheng, Xudong; He, Song; Shi, Xiaojing; Gong, Lunlun; Zhang, Heping (1 May 2016). "Aramid fibers reinforced silica aerogel composites with low thermal conductivity and improved mechanical performance". Composites Part A: Applied Science and Manufacturing. 84: 316–325. doi:10.1016/j.compositesa.2016.02.014.
- ^ "UN report: Time to seize opportunity, tackle challenge of e-waste". www.unep.org. 24 January 2019. Retrieved 31 December 2024.