Enhancement of the working pH range for degradation of p-nitrophenol using Fe2+–aspartate and Fe2+–glutamate complexes as modified Fenton reagents

We examined the degradation of p-nitrophenol (p-NP) by a modified Fenton reaction at near neutral pH conditions using FeII–aspartate and FeII–glutamate complexes as a source of Fe2+. The reaction was conducted using 0.081 mM (10 mg L−1) of p-NP in the presence of 65 mM H2O2 at room temperature. Complex concentrations of 5, 10, 15 and 20 mM (Fe2+ = 0.81, 1.62, 2.43 and 3.23 mM) were assayed which showed effective extents of p-NP degradation. In the pH range 5–7 the complex activity is pH dependent, and the optimal pH was 6.3. The degradation was monitored by an HPLC system. The rate of degradation recorded at near neutral pH in the presence of 20 mM of Fe–aspartate and Fe–glutamate complexes was equal to that obtained in the presence of Fe2+ (2.5 mM) at pH 2.7. Aspartate and glutamate complexes formed with Cu2+ or Co2+ did not show the improved degradation observed in the case of FeII–aspartate and FeII–glutamate.