Recent Advancements in the Treatment of Emerging Contaminants Using Activated Persulfate Oxidation Process

Emerging contaminants (ECs) usually refer to pesticides, polycyclic aromatic hydrocarbons (PAHs), dioxins, personal care products, cosmetics, and medications. Due to the strong demand and quick growth of these businesses, the ECs have continuously been found in alarming amounts in groundwater, surface water, and wastewater. These ECs provide a significant non-esthetic threat to the ecosystem as a whole and can cause significant non-esthetic contamination when released into the aquatic environment. The conventional wastewater treatment techniques such as activated sludge, membrane filtration, coagulation, adsorption, and ozonation showed ECs removal performance to a certain extent. In turn, numerous emerging advanced oxidation processes (AOPs), especially activated persulfate oxidation, have garnered a huge amount attention due to their outstanding performance in the remediation of ECs. This article presents a systematic and critical review of electro, sono and thermal activation of persulfate for the treatment of ECs. The effect of key parameters such as electrode materials, solution pH, persulfate concentration, current density, and temperature on electro, sono- and thermal-activated degradation of ECs was discussed. The possible reaction mechanism of ECs degradation was also elucidated in detail. It was closed with a note on the situation now and the future course of electro, sono and thermal activation in ECs degradation applications. Experiments performed in recent studies show that with the aid of persulfate in electro activation, the removal efficiency of chemical oxygen demand can be achieved up to 72.8%. Persulfate activated by sono shows 100% removal efficiency of 1,1,1-trichloroethane and sulfamethoxazole. While for thermal activation of persulfate, 100% removal efficiency of carbamazepine, atrazine and sulfamethazine was achieved. All these vital shreds of evidence are substantial enough to picture the negative impact of ECs on the environment.