Tiny self-propelled microbots can remove up to 95 percent of the lead in wastewater produced by industrial activity.
Artistic impression of the nanobots in action.
Humans are pretty effective at messing up
everything. Look at all the tech we use. It doesn't come without a cost.
Manufacturing electronics and batteries produces contaminants such as
lead, cadmium, mercury, arsenic and chromium, none of which is
particularly good for living organisms.
To
help combat this destructive effect, an international team of
researchers has developed a school of tiny microbots, each smaller than
the width of a human hair, which is capable of removing lead particles
from contaminated water more efficiently than previously developed
methods.
The robots are shaped like tiny tubes, in three layers.
Graphene oxide on the outside absorbs lead particles from the water. The
middle layer is nickel, which allows external control of the robots
using a magnetic field. The inner layer is platinum, which gives the
robots self propulsion by adding hydrogen peroxide to the water. This
interacts with the platinum, which decomposes the hydrogen peroxide into water and oxygen, propelling the microbot forwards.
The team writes in their paper, published in the journal Nano Letters,
that a swarm of the microbots can reduce the amount of lead in water
from 1,000 parts per billion to just 50 parts per billion, a reduction
of 95 percent, in just 60 minutes.
Obviously this is dependent
on the amount of water and number of microbots, but what makes it even
more impressive is that the robots can be reused. The same magnetic
field that controls the microbots can be used to retrieve them. They can
then be cleaned and used again.
Moreover, the lead ions that have been cleaned off the microbots can be reused too.
"This is a new application of smart nanodevices for environmental applications," co-author Samuel Sánchez of the Max Planck Institute for Intelligent Systems in Germany told Phys.org.
"The
use of self-powered nanomachines that can capture heavy metals 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."
The next step in the research is
to develop microbots that can clean up a much wider range of industrial
pollutants, while trying to reduce the costs of fabrication.