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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

UFS venture cleans up acid mine drainage
2015-07-06

The system that puts oxygen back into the water.

Photo: Supplied

South Africa is one of the most important mining countries in the world, beginning in the 1870s. Although the mining industry has been responsible for significant development and employment, it pollutes the environment and waters sources. Through the joint effort of a well-known mining company, the University of the Free State, and the Technology Innovation Agency (UFS/TIA) SAENSE Group, a new treatment for Acid Mine Drainage (AMD) has been developed.

The system treats the major contaminants found in acid mining wastewater effectively.  
 
The UFS remediation systems use a reservoir tank into which the AMD is pumped. The water then flows passively (without using energy) to the Barium Carbonate Dispersed Alkaline Substrate (BDAS) system. The metals and anions in the AMD react chemically with the barium carbonate and precipitate (form solids). The solids stay in the tank while the clean water is released.

The efficacy and applicability of the research was demonstrated on site in Belfast, Mpumalanga where the team constructed a pilot plant in July 2014. This patented technology has treated 1 814 400 litres of Acid Mine Drainage to date with an outflow water quality that satisfies the South African National Standards (SANS) 241:2006 & 2011 regulations for drinking water.   

Rohan Posthumus from the (UFS/TIA) SAENSE Group said: “At this stage, we do not recommend that the water should be used as drinking water, but certainly it can lower water usage in mines while finding application in dust suppression of washing processes. The team would like to complete a full characterisation of the final released water. There are currently no toxic by-products formed, and even very basic filtration can make the outflow drinking water.”

Prof Esta van Heerden’s research group from the Department of Microbial, Biochemical, and Food Biotechnology has been working on AMD research for some time, but the development of the BDAS system was started in 2013 by post-doctoral student, Dr Julio Castillo, and his junior researcher, Rohan Posthumus.

The data from the BDAS system have led to two publications in peer-reviewed journals as well as a registered patent.

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