Removal of antibiotics from aquaculture wastewater using a continuous flow/EC/PMS coupled system

Abstract

The electricity activated peroxomonosulfate (ion) coupled system (EC/PMS) has important application value in water pollution treatment. However, the traditional batch system commonly used in this coupled system poses significant challenges in treating large volume and low concentration aquaculture wastewater, such as poor mass transfer, long treatment time, and increased risk of secondary pollution. Therefore, this study proposed to introduce the continuous flow operation mode into the EC/PMS system to form a continuous flow electrocatalytic peroxomonosulfate (ion) (CF/EC/PMS) coupling system, achieving 100 % removal of tetracycline (TC) with an initial concentration of 2 mg/L. Subsequently, through cathodic optimization, an 85 % removal efficiency was achieved for antibiotics with secondary pollution risks, such as norfloxacin and NOR. It is worth noting that the secondary pollutants (such as fluoride ions, F−) generated during the degradation process have also successfully achieved a removal efficiency of 70 %. In this system, singlet oxygen (1O2) was the main active species. This system has advantages such as a processing volume of at least 3L, a wide pH range (3–9), low oxidant dosage (PMS = 2 mM), and low energy consumption (EEO = 0.018 kWh/m3 log). The coupling system effectively removes the main pollutants, and the optimized cathode coupling system achieves safe removal of fluorinated drugs, reducing the risk of secondary pollution. In summary, this study has the characteristics of low cost and engineering applicability, providing a promising method for economically, efficiently, and environmentally friendly treatment of aquaculture wastewater.