Maximizing selectivity and activity in the catalytic reduction of nitrates with formic acid under optimal pH conditions

Abstract

This study delves into the catalytic reduction of nitrate in water using a Pd 1(wt%) In 0.25(wt%) catalyst supported on alumina. Investigating the influence of formic acid concentration, pH control, and catalyst characteristics on performance and selectivity, we find that higher formic acid concentrations boost initial reaction rates until saturation, impacting activity. Stoichiometric formic acid concentration strikes the best balance between activity and N2 selectivity. Comparative studies with hydrogen highlight formic acid´s unique role in nitrate reduction. pH control using formic acid ensures full nitrate conversion, highlighting its dual role as a pH regulator and reducing agent. Additionally, the study uncovers a volcano-type behavior and surface properties affecting catalytic activity. Characterization through XPS, XRD, and SEM techniques provides valuable insights into the catalyst´s composition and distribution. This comprehensive investigation sheds light on key parameters influencing catalytic nitrate reduction, guiding optimal water treatment processes. The economically advantageous and efficient (Pd, In)-based catalyst emerges as a promising solution for nitrate removal applications, addressing global water contamination challenges.