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09 December 2022 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Dr Refilwe Mogale
Dr Refilwe Mogale received her PhD in Chemistry. She is fascinated by the ability of chemistry and science in general to solve some of the world’s most pressing issues, such as water scarcity.

“Chemistry chose me,” says Dr Refilwe Mogale, who wanted to enrol for Psychology years ago when she decided to study at the University of the Free State (UFS). 

“On the day of registration, however, as I was standing in the queue, something inside me said this was not the right choice for me. Ultimately, I chose my second option, which was a BSc degree majoring in biology, physics, and chemistry.”

“Once I started the BSc programme, I gravitated towards chemistry, and as difficult as it was juggling classes and six-hour practical sessions, I loved it. I am fascinated by the ability of chemistry and science in general to solve some of the world’s most pressing issues, such as water scarcity, alternative generation, access to antibacterial hygiene products, as well as novel strategies to cure diseases, among many other things.”

The UFS awarded Dr Mogale a PhD in Chemistry on 9 December 2022.

Addressing a global challenge

Being passionate about applied chemistry – where scientific research can be used to create products to address everyday problems – Dr Mogale focused her thesis on Aluminium- and Zirconium-based metal organic frameworks with azobenzene and stilbene dicarboxylate ligands for use in wastewater treatment. 

She has also published multiple articles on topics of environmental chemistry and wastewater management in international journals. 

Dr Mogale is of the opinion that water pollution by financially lucrative industries and access to clean drinkable water is one of our planet’s most challenging environmental and health issues. “The waste generated by some of the industries that contribute heavily to our country’s economy, such as the textile, agricultural, and medical industries, may end up in the limited drinking water resources we have. I chose my research topic because I wanted to positively contribute to this global challenge,” she says.

“My research was based on making highly porous metal-organic frameworks (MOF) to be used in the wastewater treatment technique called adsorption,” explains Dr Mogale, describing MOFs as “really cool three-dimensional ‘sponges’ that can suck up very high amounts of gases and pollutants, trapping them in their pores. These trapped materials can later be released from the pores to be re-used when MOFs are exposed to certain stimuli.”

She continues, “Low cost and simplicity make this method attractive for industrial use. Considering our current energy crisis, other methods are not ideal, since they require large amounts of energy.” 

Focused on developing highly effective adsorbent for wastewater purification systems, Dr Mogale synthesised a novel MOF with one of the highest adsorption capacities compared to existing counterparts.

According to her, should MOFs with their incredibly high surface areas – which allow them to absorb more waste than their existing counterparts – be implemented in wastewater purification systems, they would be able to address the environmental issue of water pollution and the health issue of access to drinkable water.

Tackling everyday societal issues

She is currently doing a postdoctoral fellowship in the UFS Department of Chemistry – to broaden her knowledge in chemistry beyond MOFs. Her plans are, however, to transition to industry and ultimately entrepreneurship, where she will be able to develop scientific products that can tackle everyday societal issues. 

Dr Mogale dreams of adding value to society by practically contributing to the water crisis issue through the development of low-cost water generation and purification products.

News Archive

Research by experts published in Nature
2011-06-02

 
The members of the research group are, from the left, front: Christelle van Rooyen, Mariana Erasmus, Prof. Esta van Heerden; back: Armand Bester and Prof. Derek Litthauer.
Photo: Gerhard Louw

A  research article on the work by a team of experts at our university, under the leadership of Prof. Esta van Heerden, and counterparts in Belgium and the USA has been published in the distinguished academic journal Nature today (Thursday, 2 June 2011).

The article – Nematoda from the terrestrial deep subsurface of South Africa – sheds more light on life in the form of a small worm living under extreme conditions in deep hot mines. It was discovered 1,3 km under the surface of the earth in the Beatrix Goldmine close to Welkom and is the first multi-cellular organism that was found so far beneath the surface of the earth. The worm (nematode) was found in between a rock face that is between 3 000 and 12 000 years old.

The research can shed some new light on the possibility of life on other planets, previously considered impossible under extreme conditions. It also expands the possibilities into new areas where new organisms may be found.

These small invertebrates live in terrestrial soil subjected to stress almost for 24 hours They live through sunshine, rain, scorching temperatures and freezing conditions. Through time they developed a means to cope with harsh conditions. Terrestrial nematodes (roundworms, not to be confused or related to earthworms) are among those very tough small invertebrates that deal with those conditions everywhere. After insects they are the most dominant multi-cellular (metazoan) species on the planet having a general size of 0,5 to 1 mm and are among the oldest metazoans on the planet, Nature says in a statement on the article.

They inhabit nearly every imaginable habitat form the deep seas to the acid in pitcher . Some nematodes simply eat bacteria and these are the ones we study here. Terrestrial nematodes have developed a survival stage that can take them through hard times (absence of food, extreme temperatures, too little oxygen, crowding, and more).

At the head of the research was Prof. Gaetan Borgonie of the Ghent University in Belgium and a world leader in the discipline of nematode research. He was brought into contact with the South African research leader, Prof. Esta van Heerden, who set up a cooperation agreement with the University of Ghent and Prof. Borgonie. Prof. Van Heerden manages the Extreme Biochemistry group at the UFS and the research was funded by several research grants.

The search for worms began in earnest in 2007, but it was soon clear that the sampling strategy was insufficient. A massive sampling campaign in 2008-2009 in several mines led to the discovery of several nematodes and the new nematode species Halicephalobus mephisto. It is named after the legend of Faust where the devil, also known as the lord of the underworld is called Mephistopheles.

Nature says special filters had to be designed and installed on various boreholes. Unfortunately, there is no easy way of finding a magic formula and designs had to be adapted by trial and error; improving existing designs all the time. The work of the UFS Mechanical Workshop, which manufactured, adapted and helped design it, was crucial in this respect. Filters were left on the holes for varying periods, sometimes for a few hours and sometimes for months. Prof. Derek Litthauer from the UFS played a big role in sampling, filter designs and coming up with ideas for names for the new nematode with Prof. Borgonie.

Research showed that the nematodes can live in the deep for up to 12 000 years. Three students – Armand Bester, Mariana Erasmus and Christelle van Rooyen from the UFS – did the work on this.

The importance of multi-cellular animals living in the ultra-deep subsurface is twofold: The nematodes graze on the existing bacterial population and influence their turnover. Secondly, if more complex multi-cellular organisms can survive in the deep subsurface on earth, this may be good news when looking for life on other planets where the surface is considered too inhospitable (e.g. Mars). Complex life forms can be found in ecosystems previously thought to be uninhabitable. Nature says this expands the possibilities into new areas where new organisms may be discovered.

Future research will focus on selective boreholes to look for more metazoans, so that a better idea of the complexity of the ecosystems there can be obtained. It will also look for metazoans in the deep subsurface on other continents to determine similarities and differences.

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