The effect of chloride ion on the reinforcement of zero-valent copper activated peroxysulphate

The use of the zero-valent copper activated peroxysulphate system (Cu(0)/PS system) has been widely studied for pollutant degradation. However, the presence of Cu(I) in the Cu(0)/PS system was limited due to the interaction of Cu(I) with O 2 and the occurrence of disproportionation reaction, which greatly reduced the effectiveness of the Cu(0)/PS system. To solve this problem, chloride ion (Cl − ) were introduced into the Cu(0)/PS system (Cl − /Cu(0)/PS system). When 10 mM Cl − was added to the Cu(0)/PS system, the degradation rate of tetracycline (TC) was enhanced from 48.5 % to 81.0 % within 8 min, while the reaction rate was also increased by about 2.5 times. The results indicated that the presence of Cl − significantly restricted the disproportionation and ineffective oxidation of Cu(I) by forming a stable Cu Cl complex with Cu(I). This ultimately enhanced the utilization of Cu(I). Furthermore, Cl − facilitated the reaction between Cu(0) and Cu(II) to produce CuCl, thereby establishing the Cu(II)/Cu(I) cycle, which was more conducive to the production of Cu(I). The main reactive species in the Cl − /Cu(0)/PS system were sulfate radicals (SO 4 − ), hydroxyl radicals ( OH), and reactive chlorine species (RCS). Overall, Cl − incorporation is a viable facilitator for the Cu(0)/PS system.