Wits graduate harvests sun to purify water

by | Apr 13, 2018

Manthako Lethobane at the Humphrey Raikes Building lab where she conducted her experiments as a masters student.

Research aims to change the lives of people with no access to potable water

A former Wits student, Manthako Lethobane, has come up with a way to use the power of the sun to purify water that has organic pollutants.

The National Research Foundation (NRF) announced on Thursday, April 5, that Lethobane’s research focused on synthesising nanocatalysts that can use the power of the sun to purify water that is contaminated with organic pollutants. Organic pollutants are “toxic chemicals that adversely affect human health and the environment”. (www.epa.gov/international-cooperation/persistent-organic-pollutants-global-issue-global-response)

This research may be useful to people who do not have potable drinking water. They would be able to put the catalyst inside the water they have collected, and leave it outside in the sun, so the catalyst could be activated by the sun to clean the water.

Lethobane, who graduated in March with a chemistry masters degree, told Wits Vuvuzela: “The idea behind the research was changing the properties of the nanoparticles which include size and shape, [this] would result in these nanoparticles having better effect in cleaning waste waters during photocatalysis, which is a reaction that uses light to activate a substance that modifies the rate of a chemical reaction without being involved itself.”

Inorganic coordination chemistry expert and Lethobane’s supervisor, Dr Izak Kotzé, said, “It might not clean the water from everything, so then there might be metal contaminations which will not be cleaned with this method, but it can be used in conjunction with other purification methods as well. This method can make the water safe from water organic pollutants.”

Lethobane added, “When I started my masters, I wanted to do research in a topic that is marketable and speaks to Africa’s day-to-day issues and is relevant now and for years to come. One of the biggest problems is both the scarcity of water and the non-renewable energy. When my supervisor and I bounced off ideas about this project, I knew this was it.”

Lethobane’s research was not without its challenges. “During my research I was going to the lab for a whole year with no promising results. There were days when I would leave at midnight in the lab, cause accidents [in the lab] and still have nothing to show for it. It was clear that changing little factors such as temperature, length of time and probably the energy you bring to the lab contributes a whole lot to the success of your work.”

Professor Nosipho Moloto, a nanotechnology coordination chemistry expert and Lethobane’s supervisor in this field, said, “We have released the results through a dissertation that is out there in the public domain. Other people can expand on it as we are expanding on it.”

Kotzé expressed similar sentiments: “When the information is out in the public domain, it exposes us for future collaborations with other people and institutions and that is how the university would benefit from a project like this.”

“I certainly hope my research is applied. In my current space at the [South African Breweries], we have project teams that are constantly working on ways to make an impact in society and one of these projects is actually assisting in the water scarcity in Cape Town. I certainly hope that this idea will be warmly received,” Lethobane said.

 

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