Degradation of diclofenac in water by Cu(II)-combined with heat activation of peracetic acid

Removal of diclofenac (DCF) in water by Cu(II)-combined with heat activation peracetic acid (Cu(II)-heat/PAA) was investigated, and the main active species in Cu(II)-heat/PAA system were identified. The effects of common water matrix (Cl-, SO42-, NO3-, HCO3- and natural organic matter (NOM)) on the removal of DCF were explored and the degradation of DCF in natural water was studied. As a result, the removal efficiency of DCF in Cu(II)-heat/PAA process presented a relatively faster rate than those in Cu(II)/PAA and heat/PAA systems, indicating that the combination of heat and Cu(II) had a synergistic effect on the activation of PAA. At pH 8, hydroxyl radical (center dot OH) and organic radicals (R-O center dot, CH3C(=O)O center dot and CH3C(=O)OO center dot) were the main active substances for DCF removal in Cu(II)-heat/PAA system and R-O center dot played a major role in DCF removal. Presence of SO42-, NO3- and HCO3- had little effect on DCF degradation; Cl- could weakly promote the degradation of DCF; NOM inhibited DCF removal, which resulted in the inhibition on DCF removal in lake water and river water.