Synergistic effect of Cu2+ in Fe2+/H2O2 reaction system to enhance oxytetracycline degradation in polluted water

The higher production of HO· concentration associated with the presence of a Cu2+ co-catalyst in a Fe2+/H2O2 system is reported. The synergistic effect of the co-catalyst was investigated to evaluate the possibility of further enhancement of the oxytetracycline degradation. Several experiments with different ratios of Cu2+ to Fe2+ (0.5:5, 1:5, 2:5, 3:5, and 4.5:5) were conducted to show the effect of Cu2+ co-catalysis. The parameters studied for the degradation of OTC were the initial pH (2–7), initial concentration of OTC (5–20 mg/L), and H2O2 concentration (25–180 mg/L). Almost all OTC was completely degraded at the end of the process (60 min) by (Cu2+–Fe2+)/H2O2 when the Cu2+/Fe2+ ratio was 1:5 and initial concentrations were 20 mg/L, 60 mg/L, 2 mg/L, and 0.4 mg/L of OTC, H2O2, Fe2+, and Cu2+, respectively. The effect of natural solar light was also investigated on the degradation of OTC in the Fe2+/Cu2+ system at 60 min. The results showed that the Cu2+–Fe2+/H2O2 system was more effective than the Fe2+/H2O2 system for OTC degradation, and less inhibition effect was found with the coexistence of Cl−, CO32−, HCO3−, NO3−, and NO2− ions.