Insight into reactive oxygen species and synergistic mechanism in Fenton-like system using Cu(0) and Fe(III) as the activator

Zero-valent copper (Cu(0))-triggered hydrogen peroxide (Cu(0)/H2O2) process was used to eliminate and mineralize contamination, while its oxidation efficacy was limited by the reaction of Cu(I) with O-2. In this study, ferric ion (Fe(III)) was spiked into the Cu(0)/H2O2 (Fe(III)/Cu(0)/H2O2) system, and the degradation rate of paracetamol decreased from 24.9% to 95.4%. In the Fe(III)/Cu(0)/H2O2 system, the reaction of Cu(0) and Cu(I) with Fe(III) expedited the conversion from Fe(III) to Fe(II). The reaction of Cu(I) with O-2 was weakened by the competition reaction between Cu(I) and Fe(III), promoting the generation of reactive oxygen species and increasing the utilization of Cu(0). The main reactive oxygen species for pH 4.0 was center dot OH and Fe(IV) with the contribution rate of center dot OH and Fe(IV) being 92.3% and 7.7%, but the dominant reactive oxygen species at pH 3.0 was only center dot OH in the Fe(III)/Cu(0)/H2O2 process. Especially, the contribution of Fe(IV) rose and the contribution of center dot OH decreased, when the concentrations of 20-80 mu mol/L Fe(III), 0.05-0.3 g/L Cu(0) and 50-300 mu mol/L H2O2 incremented. In the Fe(III)/Cu(0)/H2O2 process.After we increased the pH of end solution to 7.0/7.5/8.0 and leaching, the total copper in reaction solution was under 6.4/3.3/1.5 mu mol/L. In addition, Ni(II) (57.7%), Fe (II) (100%) and Mn(II) (72.4%) obviously enhanced the degradation of paracetamol in the Cu(0)/H2O2 process.