100PhDs for Africa - news from Joseph Jjagwe
© 2025 EXAF/EPFL
We are pleased to highlight the significant work of Joseph Jjagwe, supervised by Peter Wilberforce Olupot (Makerere University) and Sandro Carrara (EPFL), who propose an innovative approach to monitoring lead (Pb²⁺) contamination in drinking water. Their research showcases the power of nanomaterials science to tackle urgent environmental health challenges.
Faced with increasingly strict limits on permissible lead concentrations — reduced from 10 μg/L to 5 μg/L — the team has conducted a comprehensive review of electrochemical sensors modified with iron oxide nanoparticles (IONPs) and nanocomposites. These devices, valued for their affordability, rapid response, and simplicity of use, offer a promising alternative to conventional, costly laboratory techniques.
The study examines 23 research works over the past decade, revealing that iron oxide-modified electrodes achieve excellent sensitivity, with detection limits as low as 2.5 × 10⁻⁹ μg/L — well below recommended thresholds. Most sensors operated using square wave anodic stripping voltammetry in acetate buffer solutions, and showed optimal results at acidic pH levels (between 3 and 5.6).
Importantly, the review also highlights sustainability challenges: current practices often rely on commercial iron salts and complex preparation processes, which can hinder reproducibility and scalability. To address this, the authors advocate for future research into the use of industrial steel waste and biomass-derived activated carbon to produce and functionalize IONPs — opening new pathways toward greener and more affordable sensor technologies.
By enhancing both the sensitivity and sustainability of water quality monitoring, this work illustrates how materials science can contribute to ensuring safer drinking water worldwide.