New material helps reduce nitrate in water
According to a paper published recently on Chemical Communications, researchers from the Chinese Academy of Sciences have made a material that can make the electrocatalytic reduction of nitrate from water more efficient.
"This material is a success in improving the selectivity of electrocatalytic reduction of nitrate for N2 in water," says associate Tang Haibin, who lead the study.
Nitrate, a dangerous water pollutant, is inclined to lead to water eutrophication, algal blooms, and other ecological and environmental problems.
Among the nitrate removal methods and technologies, the electrocatalytic reduction method stands out because it can selectively convert nitrate (NO3-) into ammonium (NH4+) or nitrogen gas (N2). However, the materials of this method have not been suitable for application in practical water environments, such as lakes and rivers.
In this latest research, the team fabricated a thin copper film with a surface of porous copper foam frame. The structure was used as a cathode for electrocatalytic reduction of nitrate, thanks to the conductive porous copper foam frame. It was found that, with this material, the catalytic reduction of nitrate to N2 was significantly improved.
"In alkaline solution, the removal rate of nitrate was 93 percent with the selectivity for N2 of 99 percent; in neutral solution, the removal rate of nitrate was 94.3 percent with the selectivity for N2 of 49.2 percent", says Haibin.
The electrocatalytic test was also carried out with the practical lake water collected from a local reservoir.
"The removal rate reached as high as 91.1 percent for nitrate and the selectivity for N2 rose up to 64.2 percent," Haib further explains. "Both were higher than what we had expected."
The preparation of the cathode material in this research is simple, and it can realize high selectivity for nitrogen gas, showing the potential of electrocatalytic reductions of nitrate to nitrogen gas.
This work provides a valuable reference for further designs of stable and efficient electrocatalytic materials for removal of nitrogen in water, contributing to the treatment and protection of water ecological environment.