Electrocatalytic activity survey of some cathode materials for the reduction of nitrites and nitrates in aqueous solution

The electrochemical techniques are the subject of increasing interest on the environmental remediation methods thanks to their efficiency and their selectivity. It was classified among the cleanest methods because it does not produce sludge and undesirable intermediate byproducts. For these reasons, we have chosen this technology for the reduction of nitrites and nitrates ions from aqueous solutions. The objective of our study is the comparison of several cathodes materials performances, in order to promote an optimal electro-reduction of these ions. Indeed, we have used the copper, graphite, stainless steel and zinc as cathodes; among them, we have selected the most efficient on which we have optimized the operational conditions. The results suggested that the copper cathode was the most efficient for the reduction of both tested ions compared to the other tested materials. Therefore, the optimization of operational conditions allows us to fixed them at: scan rate=50mV/s, initial effluent concentration=100 mg/L, pH=7 and potential range of the cyclic voltammetry scanning of [-1,+1]V/SCE for both ions. Under these optimal parameters, the reduction yield after 45min was important that can achieve 96.5% and 99% for nitrites and nitrates respectively.