Electro-activated persulfate degradation of chlorophene (CP): Kinetics mechanisms and theoretical calculations

Background: Activation of persulfate (PS) to generate sulphate radicals is an effective method to remove organic pollutants from water. However, conventional methods still face challenges in efficient wastewater treatment due to the need to add additional reagents. Methods: Degradation of chlorophene (4-chloro-2-(phenylmethyl)phenol, CP) by activation of PS through electroactivation. Comprehensive experimental and product toxicity results showed that Electro-PS is an environmentally friendly and effective method for removing pollutants from water. Significant findings: When the pH value was 7.0, the current density and PS concentration were 10 mA/cm(2) and 1.0 mM, respectively, the removal rate of CP reaches 90.1 % within 10 min. The presence of humic acid (HA), NO3-, and HCO3- may deplete the active substance and thus inhibit the degradation of CP. On the contrary, Cl- could promote CP degradation due to the generation of Cl center dot. The EPR results indicated that SO4 center dot- , center dot OH, O-1(2), and O-2(center dot-) contributed to the degradation of CP, and the quenching experiments proved their contributions to be 40.6 %, 24.9 %, 11.3 % and 7.5 %, respectively. The main types of oxidation products of CP in the Electro-PS system were identified and oxidation pathways were determined by mass spectrometry, and the product structures were verified by theoretical calculations. Evaluation by the ECOSAR software showed that the toxicity of CP oxidation products was reduced.