The latest potential tool to protect Ohio’s drinking water from harmful algal blooms? Corncobs!
A sample of corncob material, left, and activated charcoal.
In order to combat drinking water contaminated by cyanotoxins, treatment plants often rely on the physical process of adsorption to remove contaminants from the water. Activated carbon (AC), also called activated charcoal, has proven to be the most efficient adsorbent available because of its large surface area with many pores.
However, commercial activated carbon — often derived from wood or coal — isn’t environmentally sustainable, and it tends to be expensive. Corncobs, meanwhile, are a common byproduct of agriculture in the Great Lakes and Midwest regions, and previous studies showed they can remove contaminants from water when modified.
Recognizing this potential solution, researchers led by Dr. Dragan Isailovic, professor in The University of Toledo’s Department of Chemistry and Biochemistry, explored whether corncobs could be used to make materials that will adsorb potent cyanotoxins from drinking water. The project was funded through the Ohio Department of Higher Education’s Harmful Algal Bloom Research Initiative (ODHE HABRI).
Dr. Dragan Isailovic, professor at The University of Toledo, holds a corncob sample in his lab. He and his collaborators evaluated how well carbonized corncobs can remove cyanotoxins from water.
“While other methods for cyanotoxin removal are available, AC is commonly used for water treatment both locally and around the world,” Isailovic said. “However, AC is often produced from carbon-containing materials that are not readily affordable and its applications for water treatment could be cost-prohibitive.”
The team received corncobs from The Andersons of Maumee, Ohio, and chemically treated and heated the corncobs to increase their surface area and porosity, creating biochar and activated carbon. These sorbent materials were characterized to determine their important properties, such as pore sizes and surface area. Then, researchers put the materials to the test by conducting experiments with samples of water taken from western Lake Erie during harmful algal blooms from 2020 to 2022.
Researchers found that corncob-based activated carbon is especially efficient at removing microcystins from HABs as well as nodularin, a closely related cyanotoxin. The activated carbon produced has an estimated sorption capacity slightly lower than commercially available activated carbon used in water treatment plants.
In their research, from left to right, Dr. Michal Marszewski, Manjula Kandage, Hasaruwani Kiridena, Yohan Sudusingha, Dr. Sharmila Thenuwara, and Dr. Dragan Isailovic found that corncob-based activated carbon is especially efficient at removing microcystins.
“It was exciting to learn that corncob-based ACs prepared by our students can efficiently remove different congeners of microcystins from the lake water, and its efficiency approaches commercial AC,” said Isailovic. “It was also a pleasure to collaborate on this project with the scientists from The University of Toledo, Ohio-based companies, and the Toledo Water Treatment Plant.”
Since then, the team has published their results in the academic journal Separations. They are also currently developing a new generation of activated corncob that is expected to have higher sorption capacity and remove nonpolar forms of microcystin more efficiently.
For more information about this research, contact Isailovic at Dragan.Isailovic@utoledo.edu.
Ohio Sea Grant is supported by The Ohio State University College of Food, Agricultural, and Environmental Sciences (CFAES) School of Environment and Natural Resources, Ohio State University Extension, and NOAA Sea Grant, a network of 34 Sea Grant programs nation-wide dedicated to the protection and sustainable use of marine and Great Lakes resources. Stone Laboratory is Ohio State’s island campus on Lake Erie and is the research, education, and outreach facility of Ohio Sea Grant and part of CFAES School of Environment and Natural Resources.