A new water desalination design from University of Michigan and Rice University researchers replaces the need for expensive chemicals using novel carbon cloth electrodes to remove boron.
Natural occurring in seawater, boron is a toxic contaminant of drinking water when it passes through traditional filtration methods designed to remove salts. With most seawater containing over twice the World Health Organization's most lenient limits, its removal is critical for desalination operations intended for human consumption.
"Most reverse osmosis membranes don't remove very much boron, so desalination plants typically have to do some post treatment to get rid of the boron, which can be expensive," said Jovan Kamcev, U-M assistant professor of chemical engineering and macromolecular science and engineering. "We developed a new technology that's fairly scalable and can remove boron in an energy-efficient way compared to some of the conventional technologies."
Their work, published in Nature Water, utilizes a novel electrode based approach to trap boron inside its pores while allowing seawater to pass through to maximize its boron capturing capability. The method reduces costs when compared to traditional methods which rely on the addition, and subsequent neutralization, of a base to capture boron.
"Our study presents a versatile platform that leverages pH changes that could transform other contaminants, such as arsenic, into easily removable forms," said Menachem Elimelech, Professor of Civil and Environmental Engineering and Chemical and Biomolecular Engineering at Rice University. "Additionally, the functional groups on the electrode can be adjusted to specifically bind with different contaminants, facilitating energy-efficient water treatment."