1 research outputs found
Overlooked Role of Coexistent Hydrogen Peroxide in Activated Peracetic Acid by Cu(II) for Enhanced Oxidation of Organic Contaminants
Cu(II)-catalyzed peracetic acid (PAA)
processes have
shown significant
potential to remove contaminants in water treatment. Nevertheless,
the role of coexistent H2O2 in the transformation
from Cu(II) to Cu(I) remained contentious. Herein, with the Cu(II)/PAA
process as an example, the respective roles of PAA and H2O2 on the Cu(II)/Cu(I) cycling were comprehensively investigated
over the pH range of 7.0–10.5. Contrary to previous studies,
it was surprisingly found that the coexistent deprotonated H2O2 (HO2–), instead of PAA,
was crucial for accelerating the transformation from Cu(II) to Cu(I)
(kHO2–/Cu(II) = (0.17–1)
× 106 M–1 s–1, kPAA/Cu(II) –1 s–1). Subsequently, the formed Cu(I) preferentially
reacted with PAA (kPAA/Cu(I) = (5.84 ±
0.17) × 102 M–1 s–1), rather than H2O2 (kH2O2/Cu(I) = (5.00 ± 0.2) × 101 M–1 s–1), generating reactive species
to oxidize organic contaminants. With naproxen as the target pollutant,
the proposed synergistic role of H2O2 and PAA
was found to be highly dependent on the solution pH with weakly alkaline
conditions being more conducive to naproxen degradation. Overall,
this study systematically investigated the overlooked but crucial
role of coexistent H2O2 in the Cu(II)/PAA process,
which might provide valuable insights for better understanding the
underlying mechanism in Cu-catalyzed PAA processes