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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 on cactus pear grabs attention of food, cosmetic and medical industry
2015-02-18

Cactus pear
Photo: Charl Devenish

The dedicated research and development programme at the UFS on spineless cactus pear (Opuntia ficus-indica) – also known as prickly pear – has grown steadily in both vision and dimension during the past 15 years. Formal cactus pear research at the UFS started with the formation of the Prickly Pear Working Group (PPWG) in June 2002. It has since gone from strength to strength with several MSc dissertations and a PhD thesis as well as popular and scientific publications flowing from this initiative.

According to Prof Wijnand Swart from the Department of Plant Sciences, the UFS is today recognised as a leading institution in the world conducting multi-disciplinary research on spineless cactus pear.

Cactus pear for animal feed

Increasing demands on already scarce water resources in South Africa require alternative sources of animal feed – specifically crops that are more efficient users of water. One alternative with the potential for widespread production is spineless cactus pear. It is 1.14 x more efficient in its use of water than Old man saltbush, 2.8 x more efficient than wheat, 3.75 x more efficient than lucerne and 7.5 x more efficient than rangeland vegetation.

“Studies on the use of sun-dried cactus pear cladodes suggest that it has the potential to provide some 25% of the basic feed resources required by South Africa’s commercial ruminant feed manufacturing sector,” says Prof HO de Waal of the Department of Animal, Wildlife and Grassland Sciences at the UFS.

Until recently, research has focused extensively on the use of cactus pear as drought fodder. However, this is now beginning to shift, with growing interest in the intensive production of spineless cactus pear for other types of animal feed. One example is the spineless cactus pear fruit, produced seasonal, yielding large quantities of fruit in a relatively short period of a few months in summer. Unless kept in cold storage, the fruit cannot be stored for a long period. Therefore, a procedure was developed to combine large volumes of mashed cactus pear fruit with dry hay and straw and preserve it for longer periods as high moisture livestock feed, kuilmoes – a high water content livestock feed similar to silage.

Cactus pear and Pineapple juice
Photo: Charl Devenish

Cactus pear for human consumption

“In addition to its use as a livestock feed, cactus pear is increasingly being cultivated for human consumption. Although the plant can be consumed fresh as a juice or vegetable, significant value can be added through processing. This potential is considerable: the plant can be pickled; preserved as a jam or marmalade; or dried and milled to produce baking flour. It can also serve as a replacement of egg and fat in mayonnaise,” said Dr Maryna de Wit from the Department of Microbial, Biochemical and Food Biotechnology.

The extraction of mucilage from fresh cladodes can form a gelling, emulsifier, and fat-replacing agent commonly found in food products such as mayonnaise and candy. During an information session to the media Dr De Wit and her team conducted a food demonstration to showcase the use of the cladodes in a juice, chicken stir-fry, biscuits and a salad.

The extrusion of cactus pear seed oil provides a further lucrative niche product to the array of uses. These include high-value organic oil for the cosmetic sector, such as soap, hair gel and sun screens.

The cladodes and the fruit also have medicinal uses. It has anti-viral, anti-inflammatory, pain killing and anti-diabetic agents. It is also high in fibre and can lower cholesterol. The fruit also prevents proliferation of cells and suppresses tumour growth and can even help to reduce a hangover.

In South Africa the outdated perception of cactus pears as thorny, alien invaders, is rapidly disappearing. Instead, farmers now recognise that cactus pear can play a vital role as a high yielding, water-efficient, multi-use crop, said Prof de Waal and the members of the Cactus Pear Team.

Facebook photo gallery
Dagbreek interview with Dr Maryna de Wit  

Research on cactus pear (read the full story)

For more information or enquiries contact news@ufs.ac.za

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