Water is life, but the same water that is meant to sustain life could be carrying hidden dangers. Across the world, toxic heavy metals released from factories, mining activities, and untreated waste continue to contaminate rivers, lakes and groundwater, threatening both ecosystems and human health. These pollutants are often invisible, odourless and difficult to remove, making water pollution one of the most complex environmental challenges of our time.

It is against this backdrop that researchers led by Dr. Lucy Kiruri, a Lecturer in the Department of Chemistry at Kenyatta University, sought to explore an innovative and affordable solution to heavy metal pollution in water sources through a project titled ‘Building of Heavy Metal Cations - Binding of Heavy Metal Cations - Ethylenediamine (Modified) Maize Tassel Complexes: Insights from the Density Functional Theory – Molecular Dynamics (DFT-MD) Simulations.’

Dr. Kiruri was among five lead researchers that were awarded Ksh. 1.5 million each under KENET’s Computational Modeling and Materials Science (CMMS) Special Interest Group (SIG) academic area in 2019. Her project fell under the category of materials modelling and development for energy conversion using basic applied sciences.

The grant facilitated the purchase of high-performance computers that were essential for running complex simulations and handling large datasets. These systems allowed the team to carry out local runs, including preparing input files before submitting jobs for computation. After the simulations were completed, the same machines were used to analyze output files and study molecular trajectories in detail.

“Since I completed my PhD in the US in 2014, this grant opened my research journey. I have published 15 papers, which I largely attribute to the support from KENET in acquiring the computers that my students use to date. The grant also opened doors for collaboration with other researcher since funding attracts partnerships and new opportunities,” said the Chemistry Lecturer.

An illustration of how modified maize tassels can be used to treat polluted water.

The study looked at how modified maize tassels can be used to remove toxic heavy metals from contaminated water through the science of biosorption. This approach was rooted in the idea that natural and readily available materials can be transformed into effective purification agents when their surface chemistry is enhanced.

To improve performance, the maize tassels were treated with ethylenediamine, a compound known to strengthen the ability of materials to bind positively charged metal ions. This treatment increased the number of active sites on the tassels, allowing them to better capture and hold metals such as lead, cadmium, and copper from polluted water.

Dr. Kiruri’s project was further enhanced by the use of advanced computational chemistry techniques, which set it apart from conventional water treatment processes. The team used Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations to examine how heavy metals interact with the modified maize tassel material at both atomic and molecular levels. This combination of environmental chemistry and theoretical simulation provided deeper insights into the binding mechanisms and helped predict how effective the material could be under different conditions.

Beyond its scientific value, the study also demonstrated that this method offers environmental and socio-economic benefits. It showed that widely available agricultural waste can be effectively used as a sustainable alternative to expensive water treatment methods such as activated carbon systems, membrane filtration, and chemical precipitation.

Dr. Kiruri undertook the project in collaboration with Dr. Isaac Mwangi, a Lecturer in the Department of Educational Communication & Technology at Kenyatta University, and Dr. Joanne Ogunah, a Lecturer in the Department of Physical Sciences at the University of Embu.