A research collaboration between the University of Edinburgh and the Indian Institute of Technology Kharagpur is progressing our understanding of photocatalytic water treatment.
Point-of-use water purification could offer a solution to millions of people worldwide who do not have access to clean, safe drinking water.
“The technology we are currently developing is sunlight-activated catalysts that can remove pathogenic and chemical contaminants in water,” says PhD student, Victoria Porley.
Victoria is a member of Professor Neil Robertson’s research group at the University of Edinburgh. The group focuses on molecular materials, dye-sensitised solar cells, luminescent materials, and conducting/magnetic materials. Earlier this year, Victoria’s research – ‘Photocatalysis for water treatment in rural India’ – won her a prize at the 2nd Commonwealth Chemistry Posters. Her excitement for the science is underpinned by the desire to make a difference. “Water is not only essential for survival, with the quality and accessibility of water impacting the health of every individual on the planet, but also the opportunities available to each and every one of us,” says Victoria.
“It is a sad reality that, without a dependable supply of safe drinking water close to home, many people globally will have to travel long distances to collect water, which can lead to insufficient quantities collected, time out of work or school, which often impacts women and girls most, and, of course, illness if the most accessible water supply is not well-treated.”
The global water crisis
In 2020, around 1 in 4 people lacked safely managed drinking water in their homes and nearly half the world’s population lacked safely managed sanitation.1 At the onset of the pandemic, 3 in 10 people worldwide could not wash their hands with soap and water within their homes.2
The availability and sustainable management of clean water and sanitation for all is one of the United Nations 17 Sustainable Development Goals (SDGs). Progress has been made but, at the current rate, 1.6 billion people will still be without safely managed drinking water by 2030.3
Contaminated water can transmit diseases such as diarrhoea, cholera, dysentery, typhoid and polio. And it is estimated that contaminated water is responsible for 485,000 diarrhoeal deaths each year.4 Those living in rural regions, and children in particular, are especially vulnerable to water-related diseases due to the lack of access to basic services.
In 2019, Victoria spent three weeks at the Indian Institute of Technology (IIT) Kharagpur in India. Under the supervision and guidance of Professor B C Meikap, Professor Mishra and Dr Somnath Ghosal, Victoria visited rural villages to gain greater insight into the water sources that people rely on, and current water treatment methods used.
“This gave a much better context for knowing how my research fits in, and the requirements the technology I have been developing would need to fulfil,” says Victoria.
People-first chemistry solutions
The collaboration between Professor Robertson’s research group and IIT Kharagpur illustrates how crucial such relationships are to enabling progress in tackling the SDGs. Solutions must consider the cultural, social and economic factors that impact communities.
“When addressing real-world problems, it is of paramount importance that the context is carefully understood and a solution is developed that is actually addressing the needs and desires of the people it is intended for, with respect and care for different ways of life.”
“For example, many research groups have developed fascinating and extremely well-performing materials for water treatment, but these may have complicated synthesis routes that would be difficult to scale up, or may require expensive, rare or toxic chemicals. Though these push scientific understanding forward and help us understand fundamental mechanisms in play, and could be very useful for water treatment in different contexts, for rural areas, this would inhibit applicability.”
“Once a material is developed and looks to be promising in the lab, I can then perform field testing which helps to check the validity of the material in a real-world context, with genuine water samples and sunlight. This has helped keep my research on track and learn much more about the best practical set-ups to make the treatment as user-friendly as possible.”
While there is no one-size-fits-all water treatment method, Victoria explains that solar activated water purification is easily scalable and adaptable for different levels of chemical and pathogenic contamination, and varying levels of light available.
“Recent field tests in India were performed using 500 ml plastic bottles as these are widely available and reflect a personal scale that can be used as a point-of-source water treatment method. This could be scaled using larger plastic bottles that are also widely available, e.g. two litres, but, for community-scale, larger volumes would be required. This could involve bespoke containers being made, and add complexities to the set-up (for example, at larger scales, things like stirring the water may need to be considered). The initial cost of the system would therefore go up, but this could be outweighed by the greater extent of water treatment achieved through other methods, such as simple solar water disinfection (SODIS).
“Therefore, when thinking about scaling up, it is important to consider the desires of the communities that could be potential users – what would people be willing to pay? How likely is continued use after installation? Could this provide a local enterprise opportunity to help instal and maintain the treatment facility? Questions like these are currently being explored as part of a socio-economic study being conducted in collaboration between our team in Edinburgh and scientists at IIT Kharagpur in order to learn about how best to take this technology forward in a way that appropriately addresses people’s needs at various scales.”
Taking the research to a wider audience
Having the opportunity to share her research at the virtual 2nd Commonwealth Chemistry Posters in 2021 meant that Victoria could reach a wider audience and meet chemists from across the Commonwealth.
“The poster event was really great for engaging with other scientists outside of my direct research field, but all with similar motives in addressing the SDGs. It is really inspiring to see how this type of research is taking place on a global scale, which reflects its importance! Some of the scientists in attendance were working on similar projects concerning photocatalytic water treatment, and that was really interesting to hear about the different ways it can be harnessed and applied for different contexts, showing just how useful it can be.”
At the time of publishing, Victoria is in the final stages of her PhD at the University of Edinburgh. She hopes to do more studies covering the removal of various pathogens, including Cryptosporidium which is notorious for causing illness and being difficult to remove from water with traditional methods such as chlorination.
1,2 WHO/UNICEF Joint Monitoring Programme (JMP) for Water Supply, Sanitation and Hygiene (WASH) Progress on household drinking water, sanitation and hygiene 2000–2020.
3 JMP Progress on household drinking water, sanitation and hygiene 2000–2020.
4 Drinking water factsheet, 2019, WHO
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