When added to water, conventional coagulants like aluminum sulfate and other metallic salts remove larger particles from water by causing them to group together into larger formations and settle. However, these coagulants do not remove smaller particles dissolved in water, making further treatment methods necessary. The practice of using multiple technologies for water treatment is energy-intensive and expensive.
To address this, researchers synthesized a novel, highly stable nanocoagulant that differs from conventional coagulants in structure, performance, and behavior. In additional to removing suspended particles, the nanocoagulant also removes small dissolved contaminants.
The team synthesized the coagulant using organic and inorganic components to replicate the structure of the sea anemone Actinia. Similar to Actinia, the nanocoagulant has a core-shell structure that turns inside out in water. The shell destabilizes and enmeshes larger suspended particles, while the exposed core captures the smaller, dissolved ones. It removes a broad spectrum of contaminants, from trace micropollutants to larger particles, many of which elude conventional methods and pose significant public health concerns.
“The ability to remove nitrate was quite surprising, as traditional water coagulants exhibit negligible removal of nitrate,” said Menachem Elimelech, Roberto C. Goizueta Professor of Chemical & Environmental Engineering at Yale University. It is also critical to water treatment, since nitrate contamination is associated with “blue-baby” syndrome, a potentially fatal condition that affects young children in some parts of the world.
Because it is a one-step process, said Professor Huazhang Zhao of Peking University, the work holds promise for replacing current water treatment methods and greatly reducing the operating costs of water treatment.