Turning waste into resources for drinking water

How did you hear about the Excellence in Africa initiative's 100 PhDs programme?
I first came across the call for applications on the Makerere University website in 2021. This led me to further explore the EXAF website, where I learned more about the programme and its opportunities.

What prompted you to apply?
The fact that this opportunity could offer upto 80,000 CHF gave an assurance of executing the PhD research without any financial hindrances. Moreover, the possibility to visit EPFL and be co-supervised by a professor at one of the world’s top universities was a unique chance to gain exposure and enhance my research skills.

Was the application process easy for you?
The process was straightforward. The templates and supporting documents were clear, which made the application smooth to complete.

Can you describe your project? What is/are your research question(s)?
My PhD research focuses on the development of iron oxide–activated carbon nanocomposites for the detection and removal of pollutants from drinking water. The approach relies on transforming waste into resources:

• iron dust waste from steel industries is used to generate magnetic iron oxide nanoparticles (IONPs);
• rice husks waste is converted into activated carbon (AC).

The AC is further used to enhance the properties of IONPs to generate IONP@AC nanocomposite. The generated nanocomposites are used to modify electrochemical sensors for detection of heavy metal ions (HMIs) in drinking water. Furthermore, the same nanocomposite is used to remove the HMIs from water. The following research questions guide the study:

1. Do the characteristics of magnetic iron oxide nanoparticles developed from Iron powder waste comparable to those derived from commercial ferric and ferrous salts?
2. How does the functionalization of iron oxide nanoparticles with rice husk based activated carbon affect its properties?
3. Does modification of electrochemical sensors with iron oxide-activated carbon nanocomposites improves their sensitivity, and selectivity towards heavy metals pollutants?
4. What are the adsorptive and antimicrobial efficiencies of Iron oxide –rice husk activated carbon nanocomposites towards HMIs in environmental water samples?

Could you give some practical applications of your research?
First, the research is utilizing waste materials from both industrial (iron dust waste) and agricultural (rice husks waste) to generate a product for environmental application. Secondly, the modification of electrochemical sensors with the developed nanocomposites will enable real time and insitu detection of heavy metal ions in real waste samples. The use of the nanocomposites for removal of the pollutant will also solve the challenges of sophiscated treatment technologies such as membrane filtration reverse osmosis and advanced oxidation process

What is the scientific challenge of your research topic?
The development of nanoparticles requires highly controlled laboratory conditions (such as use of fume hoods) and advanced characterization equipment, both of which are costly and need specialized expertise. This makes the research particularly demanding.

Could you briefly introduce your supervisor and co-supervisor?
My Supervisor is Associate Professor Peter Wilberforce Olupot. He is the Head of Department of Mechanical Engineering of Makerere University, and his area of specialization is in Materials Science and Engineering. Prof Olupot has published over 40 peer reviewed articles in the area of materials science.

My Co-Supervisor is Professor Sandro Cararra. Prof Sandro is the Head of Bio/CMOS interfaces laboratory at EPFL. He has an outstanding experience in the field of design of nanoscale biological CMOS sensors. Prof. Cararra has more than 340 scientific publications and is author of 14 patents. He is the Editor-in-Chief of the IEEE Sensors Journal.

What are the advantages of co-supervision between your supervisor in Africa and your co-supervisor at EPFL?
The co-supervision has enabled me get exposed to different environments and widen my academic network. Additionally, the two supervisors are experts in different fields and thus, this is building my capacity both in materials science and electrochemistry for environmental applications

How will the collaboration with EPFL help you meet the scientific challenge described in the previous question?
EPFL has well established and fully equipped laboratories which has enabled me perform my experiments without any drawbacks. The personnel responsible for the labs/equipment are very resourceful and experienced, with timely responses to any inquiries raised. Additionally, the training given before having full access to the labs and/or equipment has enabled me become an independent confident researcher.

Can we talk about your stay in Switzerland? Was it easy to prepare your site for Switzerland?
The preparation was quite challenging. I had to apply twice for a visa: the first attempt was rejected because of timing, and during the second attempt I waited for two and a half months before approval. This delay prevented me from attending the summer school in Morocco, as my passport was held at the Swiss Embassy in Nairobi.

Once in Switzerland, however, my stay was very pleasant. I lived in Neuchâtel, only a two-minute walk from EPFL Microcity. Finding this accommodation was not easy, as most rentals were for six months or more, while my stay was only for two months.

What did you do?
I remained in close contact with the EXAF administrators as well as the laboratory administrator. They provided great support, especially with the visa process. Carine also shared leads that eventually helped me secure housing.

Do you have any amusing or unexpected anecdotes to share with us about your stay?
My stay in Neuchatel was so amazing!, my land-lady was so accommodative and supportive. The apartment was located in a very prime setting with full access to the shopping mall, the stadium, the university and the lake. The fact that I had full access to university made my research activities so smooth. I surely can’t ask for more!

What does excellence mean to you?
Excellence is having a dream/goal without an assurance of the resources to support this dream, but moving with hope each day through continuous improvement and self-determination, and one day having this dream/goal realized.