Determination of nitrate reduction reaction products on Cu catalyst by UV-Vis spectroscopy and online gas chromatography

Abstract

Nitrate, well-known as a harmful contaminant in waste and groundwater systems, is an issue in Vietnam and many other countries globally. Many techniques have been developed for the treatment of nitrated polluted water, in which the electrochemical reduction of nitrate is attracting many researchers due to its high treatment efficiency with any type of water, scalability with low investment, and maintenance costs. A key challenge to study the electrochemical reduction of nitrate is determining reaction products conveniently and accurately for better evaluation of the yield and efficiency of the main products on each catalyst. In this study, a semiflow cell was developed and utilized as an electrochemical cell for the reduction of nitrate, allowing the gas to flow directly into the gas chromatography (GC) for N₂ detection during the reaction. Meanwhile, UV-Vis spectroscopy was utilized to detect NO₂- and NH₄+ after the reaction. The nitrate reduction on the Cu cathode was tested to prove the suitability of the electrolysis and analysis setup for the nitrate reduction reaction.