Microbots can clean up polluted water

April 11, 2016 by Lisa Zyga feature
Illustration of a self-propelled graphene oxide-based microbot for removing lead from wastewater. Credit: Vilela, et al. ©2016 American Chemical Society

(Phys.org)—A new study shows that a swarm of hundreds of thousands of tiny microbots, each smaller than the width of a human hair, can be deployed into industrial wastewater to absorb and remove toxic heavy metals. The researchers found that the microbots can remove 95% of the lead in polluted water in one hour, and can be reused multiple times, potentially offering a more effective and economical way to remove heavy metals than previous methods.

The researchers, Diana Vilela, et al., have published a paper on the lead-adsorbing microbots in a recent issue of Nano Letters.

"This work is a step toward the development of smart remediation system where we can target and remove traces of pollutant without producing an additional contamination," coauthor Samuel Sánchez, at the Max-Planck Institute for Intelligent Systems in Stuttgart, Germany; the Institute for Bioengineering of Catalonia in Barcelona; and the Catalan Institution for Research and Advanced Studies in Barcelona, told Phys.org.

Heavy metal pollution in water is a common problem stemming from industrial activities, including the manufacturing of batteries and electronics, as well as mining and electroplating. These activities produce metals such as lead, arsenic, mercury, cadmium, and chromium, all of which pose a safety hazard to living organisms and the environment.

In the new study, the researchers focused specifically on removing lead from wastewater by designing tube-shaped microbots with three functional layers. The outer layer of graphene oxide adsorbs the lead from the water. The middle layer, nickel, makes the microbots ferromagnetic so that their direction of motion can be controlled by an external magnetic field. The inner layer, platinum, gives the microbots the ability to self-propel themselves through water. When hydrogen peroxide is added to the wastewater, the platinum decomposes the hydrogen peroxide into water and oxygen microbubbles, and ejecting the microbubbles from the back of the microbot propels it forward.

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Magnetic guidance of a microbot. Credit: Vilela, et al. ©2016 American Chemical Society

When the microbots are finished adsorbing the lead, a magnetic field can be used to collect them all from the . Then the microbots are treated in an acidic solution to remove the lead ions, which can later be recovered and reused. The microbots can also be reused for further clean-up.

"This is a new application of smart nanodevices for environmental applications," Sánchez said. "The use of self-powered nanomachines that can capture from contaminated solutions, transport them to desired places and even release them for 'closing the loop'—that is a proof-of-concept towards industrial applications."

In the future, the microbots could even be controlled by an automated system that magnetically guides the swarm to accomplish various tasks.

"We plan to extend the microbots to other contaminants, and also importantly reduce the fabrication costs and mass-produce them," Sánchez said.

The combination of self-propelled robots with functional layers also opens the doors for similar designs that could have applications in areas including drug delivery and sensing.

Explore further: Microbots individually controlled using 'mini force fields'

More information: Diana Vilela, et al. "Graphene-Based Microbots for Toxic Heavy Metal Removal and Recovery from Water." Nano Letters. DOI: 10.1021/acs.nanolett.6b00768

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12 comments

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paul_thrush
3.7 / 5 (3) Apr 11, 2016
What's happens to the animals that eat the microbots?
topkill
1 / 5 (3) Apr 11, 2016
....OR we could stop dumping SH|T into the water in the first place! Wow, I'm a frigging genius. I'll take my Nobel now, thank you.
Edenlegaia
3.5 / 5 (4) Apr 11, 2016
....OR we could stop dumping SH|T into the water in the first place! Wow, I'm a frigging genius. I'll take my Nobel now, thank you.


And do nothing with the shit already there? Veto for your Nobel.
xponen
4.8 / 5 (4) Apr 11, 2016
Is this the first microbot with practical application?!! Or did I miss a lot of them?
Dug
not rated yet Apr 11, 2016
Don't look now, but a host of naturally occurring organisms clean up the water already - and for free. The problem is that human over population has exceeded this natural ability. Thinking that the planet can now provide even more of our finitely limited critical resources to make bots to correct our over population is exceptionally bad thinking. Only one thing equals less anthropogenic environmental impacts (climate change, pollution, species and ecosystem displacements, etc.) - about 5 billion less anthropogenes.
We-Are-NerdsPorn
not rated yet Apr 12, 2016
Amazing. Isn't it ??. I truly believe we are living in future. I also wrote an article amazed by this. Hope it helps.

nerdsporn.com/7-amazing-facts-about-microbes-you-should-know/
antialias_physorg
5 / 5 (4) Apr 12, 2016
What's happens to the animals that eat the microbots?

We're talking about catch basins for toxic substances . There are no animals there.

Is this the first microbot with practical application?!!

Similar bots are being developed (by the same group at Max Planck) for medical applications for targetting blood clots and cancer cells.
BerylliumErbide
3.7 / 5 (3) Apr 12, 2016
....OR we could stop dumping SH|T into the water in the first place! Wow, I'm a frigging genius. I'll take my Nobel now, thank you.


You should probably consider that maybe, JUST MAYBE, this research isn't necessarily targeted at environmental pollution as you're implying in the first place.

LOTS of chemistry in industry is done in water-based environments - meaning, when the chemists who make the drugs that save your life from an infection or cancer produce said drug, they're carrying out those chemical reactions in water with a whole lot of other stuff present.

When they've finished the reaction they're left with at least two things - a liquid containing that life-saving drug, and another liquid containing all the other junk that was left over from making that drug. That left-over mix of waste may have all sorts of stuff in it, including lead. These microbots can remove the lead from that waste and make it more safe.
BerylliumErbide
5 / 5 (2) Apr 12, 2016
What's happens to the animals that eat the microbots?


Good question! Hopefully that won't be a concern, seeing as the microbots can be pulled from water with a magnet. My guess is that this research is going to be targeted towards industrial applications of chemistry, where heavy metals like lead are often unfortunate necessities in the steps for producing the kinds of chemicals that are turned into useful things, such as anti-cancer drugs and plastics.

Using these bots they can clean up the waste water (read: the water left over after removing the desired chemical products from it) and allow scientists and engineers to dispose of the waste water more easily. Lead and other heavy metals make disposing wastewater more difficult and more costly, which is often a reason (regardless of how bad of one) that companies decide to cut corners and improperly dump chemical waste. Hopefully these kinds of advancements change that.
manifespo
not rated yet Apr 12, 2016
Magnetic guidance of a microbot. Credit: Vilela, et al. ©2016 American Chemical Society
When the microbots are finished adsorbing the lead, a magnetic field can be used to collect them all from the water.

Read more at: http://phys.org/n...html#jCp
topkill
5 / 5 (1) Apr 16, 2016
....OR we could stop dumping SH|T into the water in the first place! Wow, I'm a frigging genius. I'll take my Nobel now, thank you.


You should probably consider that maybe, JUST MAYBE, this research isn't necessarily targeted at environmental pollution as you're implying in the first place.


Did you even read the article you stupid asshat?...

"Heavy metal pollution in water is a common problem stemming from industrial activities, including the manufacturing of batteries and electronics, as well as mining and electroplating. These activities produce metals such as lead, arsenic, mercury, cadmium, and chromium, all of which pose a safety hazard to living organisms and the environment."

Don't comment if you're too F'ing stupid to read the article first.
topkill
5 / 5 (1) Apr 17, 2016
....OR we could stop dumping SH|T into the water in the first place! Wow, I'm a frigging genius. I'll take my Nobel now, thank you.


And do nothing with the shit already there? Veto for your Nobel.


Sigh. You missed the point: Stop dumping it in the water and causing the problem. NOBODY said to stop trying to fix the stuff already there.

Question for you: So I take an extreme/green position to stop polluting and your first assumption is that I'd be happy to leave existing pollution where it is? Talk about ironically stupid assumptions.

Do you have any logical abilities...at all? Again...sigh.

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