SoylentNews is people
SoylentNews
from the do-they-have-a-citrus-smell? dept.
Orange peels used to extract valuable metals from spent batteries:
Just because a lithium-ion battery no longer holds a charge doesn't mean it no longer holds any value. It still contains useful metals, which can now be reclaimed via a more eco-friendly technique – the key ingredient is orange peel waste.
[...] With that limitation in mind, scientists at Singapore's Nanyang Technological University tried using orange peels instead of the usual acids and hydrogen peroxide. More specifically, they utilized oven-dried orange peels that had been ground into a powder, combined with citric acid obtained from citrus fruit.
Doing so, the researchers were able to extract about 90 percent of the lithium, cobalt, nickel and manganese from spent lithium-ion batteries. This level of efficiency is roughly what had been achieved previously. Importantly, though, when using the orange peels, the residue was found to be non-toxic.
[...] The researchers used the reclaimed metals in new lithium-ion batteries, that have a charge capacity similar to that of commercially available models. Further testing is now being conducted, to see if the new batteries last for a comparable number of charge/discharge cycles.
A paper on the research, which is being co-led by Prof. Madhavi Srinivasan, was recently published in the journal Environmental Science & Technology.
Journal Reference:
Zhuoran Wu, Tanto Soh, Jun Jie Chan, Shize Meng, Daniel Meyer, Madhavi Srinivasan, and Chor Yong Tay. Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries . Environmental Science & Technology 2020 54 (15), 9681-9692
DOI: 10.1021/acs.est.0c02873
(Score: 3, Interesting) by Immerman on Thursday September 03 2020, @02:47PM
The nickle is what's recycled - the non-toxic residue is what's left over after the nickel, etc. has been removed.
Once you have ions in solution fully precipitating them out is relatively trivial, so I would assume the 10% that's not recycled failed to react with the solvent in the first place - presumably stuff already locked into some more stable compound, which will tend to be non-toxic.
Now, I probably still wouldn't want to grow my vegetables in the residue, or have it dumped in my drinking water reservoir, but keep in mind that the alternative (for now at least) is to either use the far more toxic recycling processes already available, or have unprocessed batteries leaching toxic chemicals into the ground, plus producing all the mining tailings from extracting fresh nickel, etc.
It's not perfect, but perfection is the enemy of good enough (and of better than now).