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23 November 2021 | Story Leonie Bolleurs | Photo Tania Allen
Dr Jana Vermaas and Ketshepileone Matlhoko are working on research that leaves your washing clean and fresh without the use of any detergents, which is also beneficial to the environment.

Cold water or hot water? Omo or Skip? Laundry blues is a reality in most households and when you add stains to the equation, then what was supposed to be part of your weekly household routine, becomes frustrating and time consuming. 

Researchers at the University of the Free State (UFS) are conducting research that is putting a whole new environmentally friendly spin on laundry day.

Sustainability and environmental conservation

Dr Jana Vermaas, Lecturer in the Department of Sustainable Food Systems and Development at the UFS, is passionate about textiles and sustainability – almost a decade ago, she conducted a study on the efficacy of anolyte as a disinfectant for textiles.

She describes the process: “During electrochemical activation, a dilute solution of natrium chloride/salt passes through a cylindrical electrolytic cell where the anodic and cathodic chambers are separated. Two separate streams of electrochemically activated water are produced. Anolyte as water was produced at the positive electrode and has a low pH, high oxidation-reduction potential and contains dissolved chloride, oxygen, and hydroxyl radical. It also has an antimicrobial effect.”

The benefits of this process are in line with her enthusiasm for environmental conservation. 

According to Dr Vermaas, the amount of water and chemicals used to clean textile articles is massive. “Chemicals used to disinfect, for example, hospital laundry, are hazardous. Not all laundries in the industry have a closed loop system or try to remove the chemicals before the wastewater is discarded.”

“Different amounts of detergents have various effects on our fauna and flora. Due to their low biodegradability, toxicity, and high absorbance of particles, detergents can reduce the natural water quality, cause pH changes in soil and water, lead to eutrophication (too many nutrients), reduce light transmission, and increase salinity in water sources.”

“But with the catholyte and anolyte process, water returns to its original status, which means that the water solution becomes inactive again after production where it existed in a metastable state while containing many free radicals and a variety of molecules for 48 hours. Thus, no chemicals are left in the wastewater. The water can therefore be recycled, not as potable water but, for example, to flush toilets or to water plants.

“We should do what we can to save water,” she says. 

Should you, like Dr Vermaas, also feel strongly about protecting the environment and want to obtain one of these machines that leaves your washing clean and fresh without the use of any detergents, you will be able to find such an appliance in South Arica. However, it does not come cheap. “It is a bit costly for residential use, but might be more accessible in the future,” states Dr Vermaas, who is of the opinion that it is a more sustainable option for commercial laundries.

Detergency properties and colourfastness 

Recently, more research has been conducted on this topic, but with a focus on the detergency properties of the catholyte to clean different textile fibres (natural and synthetic). Catholyte, she explains, is water produced at the negative electrode with a high pH, low oxidation-reduction potential, containing alkaline minerals. It also has surface active agents that increase the wetting properties, and it is an antioxidant. 

“A master’s student in the department, Ketshepileone Matlhoko, will be submitting her dissertation at the end of November on the possibility of using the catholyte as a scouring agent to clean raw wool,” says Dr Vermaas. 

The department is also conducting studies to investigate the influence of both catholyte and anolyte on colourfastness.

*Graphic: Production of electrolysed water (Nakae and Indaba, 2000). Diagram: Supplied



News Archive

NRF grants of millions for Kovsie professors
2013-05-20

 

Prof Martin Ntwaeaborwa (left) and Prof Bennie Viljoen
20 May 2013


Two professors received research grants from the National Research Foundation (NRF). The money will be used for the purchase of equipment to add more value to their research and take the university further in specific research fields.

Prof Martin Ntwaeaborwa from the Department of Physics has received a R10 million award, following a successful application to the National Nanotechnology Equipment Programme (NNEP) of the NRF for a high-resolution field emission scanning electron microscope (SEM) with integrated cathodoluminescence (CL) and energy dispersive X-ray spectrometers (EDS).

Prof Bennie Viljoen from the Department of Microbial, Biochemical and Food Biotechnology has also been awarded R1,171 million, following a successful application to the Research Infrastructure Support Programme (RISP) for the purchase of a LECO CHN628 Series Elemental Analyser with a Sulphur add-on module.

Prof Ntwaeaborwa says the SEM-CL-EDS’ state-of-the art equipment combines three different techniques in one and it is capable of analysing a variety of materials ranging from bulk to individual nanoparticles. This combination is the first of its kind in Africa. This equipment is specifically designed for nanotechnology and can analyse particles as small as 5nm in diameter, a scale which the old tungsten SEM at the Centre of Microscopy cannot achieve.

The equipment will be used to simultaneously analyse the shapes and sizes of submicron particles, chemical composition and cathodoluminescence properties of materials. The SEM-CL-EDS is a multi-user facility and it will be used for multi- and interdisciplinary research involving physics, chemistry, materials science, life sciences and geological sciences. It will be housed at the Centre of Microscopy.
“I have no doubt that this equipment is going to give our university a great leap forward in research in the fields of electron microscopy and cathodoluminescence,” Prof Ntwaeaborwa said.

Prof Viljoen says the analyser is used to determine nitrogen, carbon/nitrogen, and carbon/hydrogen/nitrogen in organic matrices. The instrument utilises a combustion technique and provides a result within 4,5 minutes for all the elements being determined. In addition to the above, the machine also offers a sulphur add-on module which provides sulphur analysis for any element combination. The CHN 628 S module is specifically designed to determine the sulphur content in a wide variety of organic materials such as coal and fuel oils, as well as some inorganic materials such as soil, cement and limestone.

The necessity of environmental protection has stimulated the development of various methods, allowing the determination of different pollutants in the natural environment, including methods for determining inorganic nitrogen ions, carbon and sulphur. Many of the methods used so far have proven insufficiently sensitive, selective or inaccurate. The availability of the LECO analyser in a research programme on environmental pollution/ food security will facilitate accurate and rapid quantification of these elements. Ions in water, waste water, air, food products and other complex matrix samples have become a major problem and studies are showing that these pollutants are likely to cause severe declines in native plant communities and eventually food security.

“With the addition of the analyser, we will be able to identify these polluted areas, including air, water and land pollution, in an attempt to enhance food security,” Viljoen said. “Excess levels of nitrogen and phosphorous wreaking havoc on human health and food security, will be investigated.”

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