Optimization of the N2 generation selectivity in aqueous nitrate reduction using internal circulation micro-electrolysis

The reduction of nitrate using internal circulation micro-electrolysis te chnology(ICE) was investigated.The effect of the reaction time,initial pH,Fe/C ratio,and aeration rate on the nitrate reduction was investigated using a single factor experiment.Based on the results of the single factor experiment,a response surface methodology(RSM) was applied to optimize the Ngeneration selectivity.The effects and interactions of three independent variables were estimated using a Box-Behnken design.Using the RSM analysis,a quadratic polynomial model with optimal conditions at pH=8.8,Fe/C=1:1,and an aeration rate of 30 L·minwas developed by means of the regre ssion analysis of the experimental data.Using the RSM optimization,the optimal conditions yielded a Ngeneration selectivity of 72.0%,which is in good agreement with experimental result(73.2%±0.5%) and falls within the 95% confidence interval(IC:66.8%-77.3 %) of the model results.This indicates that the model obtained in this study effectively predicts the Ngeneration selectivity for nitrate reduction by the ICE process,thus providing a theoretical basis for process design.