Microbots hailed as success for cleaning up polluted water


By Tanya Harrington

Stating that “heavy metal contamination in water is a serious risk to the public health and other life forms on earth,” several researchers from universities and institutions around the world have collaborated to theorise about the mass production of a “GOx-microbot” – a piece of nanotechnology with the capability to remove damaging pollutants from water without leaving any residue behind.

The microbots are reusable, self-powering, and are described as being in a cylindrical tube shape and “smaller than the width of a human hair.” Specifically, the microbots target lead pollution – which, considering the catastrophic events surrounding the current water crisis in Flint, Michigan, is certainly a very real problem we face.

The researchers, Diana Vilela, Jemish Parmar, Yongfei Zeng, Yanli Zhao, and Samuel Sánchez, designed the microbots to have three “layers,” and to work in polluted water which has had hydrogen peroxide added to it. The hydrogen peroxide is designed to react with the innermost layer of the microbots, which consists of platinum – the platinum would then decompose the hydrogen peroxide into “microbubbles” of water and oxygen, with the expulsion of these bubbles from inside the microbot providing enough force to propel it through the water. The second, or middle, layer of the microbots is made up of nickel, the purpose of which is to allow magnets to pull them out of the water once the pollutants have been dealt with. Thirdly, the outer layer of the microbots is made out of graphene oxide, which adsorbs lead ions from the wastewater.

The high absorption of lead by these microbots, alongside the fact that they leave no harmful residue behind and can later be “cleansed” of lead ions through a pH readjustment and reused, makes this an incredibly efficient and economical model for dealing with rising heavy metal pollution levels worldwide. Researcher Samuel Sánchez particularly stressed the importance of creating a “smart remediation system where we can target and remove traces of pollutant without producing an additional contamination,” when designing the microbots.

The outcomes of this study could potentially lead to improved methods of dealing with the fallout of a rise of industrial activity, such as mining and the creation (and disposal) of batteries and electronics.

Unfortunately, there are certain issues with the production of these microbots that could mean putting them into widespread action may not be plausible for some time. The cost of creating such complex, yet tiny technology, alongside the fact that many of the production materials, such as platinum, are expensive to acquire and work with, means that a suitable business model and source of funding will need to be established before the microbots can be mass produced.

However, the idea of a self-propelling microbot has now inspired researchers from other fields, such as medicine, to theorise about the prospect of using such nanotechnology for both the discovery and treatment of disease in humans. So, it seems that despite technical and financial issues which may need to be dealt with in the early stages of this technology’s development, microbots could provide new solutions for problems in many areas in the years to come.

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