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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

Well-established root system important for sustainable production in semi-arid grasslands
2015-02-24

Plot layout where production and root studies were done
Photo: Supplied

The importance of a well-established root system for sustainable production in the semi-arid grasslands cannot be over-emphasised.

A study of Prof Hennie Snyman from the Department of Animal and Wildlife and Grassland Sciences at the University of the Free State is of the few studies in which soil-water instead of rainfall has been used to estimate above- and below-ground production of semi-arid grasslands. “In the past, plant ecological studies have concentrated largely on above-ground parts of the grassland ecosystem with less emphasis on root growth. This study is, therefore, one of the few done on root dynamics in drier areas,” said Prof Snyman.

The longevity of grass seeds in the soil seed bank is another aspect that is being investigated at present. This information could provide guidelines in grassland restoration.

“Understanding changes in the hydrological characteristics of grassland ecosystems with degradation is essential when making grassland management decisions in arid and semi-arid areas to ensure sustainable animal production. The impact of grassland degradation on productivity, root production, root/shoot ratios, and water-use efficiency has been quantified for the semi-arid grasslands over the last 35 years. Because of the great impact of sustainable management guidelines on land users, this study will be continuing for many years,” said Prof Snyman.

Water-use efficiency (WUE) is defined as the quantity of above- and/or below-ground plant produced over a given period of time per unit of water evapotranspired. Sampling is done from grassland artificially maintained in three different grassland conditions: good, moderate, and poor.

As much as 86, 89 and 94% of the roots for grasslands in good, moderate and poor conditions respectively occur at a depth of less than 300 mm. Root mass is strongly seasonal with the most active growth taking place during March and April. Root mass appears to be greater than above-ground production for these semi-arid areas, with an increase in roots in relation to above-ground production with grassland degradation. The mean monthly root/shoot ratios for grasslands in good, moderate, and poor conditions are 1.16, 1.11, and 1.37 respectively. Grassland degradation lowered above- and below-ground plant production significantly as well as water-use efficiency. The mean WUE (root production included) was 4.79, 3.54 and 2.47 kg ha -1 mm -1 for grasslands in good, moderate, and poor conditions respectively.

These water-use efficiency observations are among the few that also include root production in their calculations.

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