Application of photoelectro-fenton process modified with porous cathode electrode in removing resistant organic compounds from aquatic solutions: modeling, toxicity and kinetics

Abstract

The presence of antibiotics in the environment as persistent micropollutants, due to their widespread consumption, has increased the concerns about the harmful effects of these compounds on human and animal health. Advanced oxidation processes are one of the most effective methods to remove these types of organic pollutants. In this study, amoxicillin (AMX) removal in a modified photoelectro-Fenton (PEF) reactor in which porous stainless steel was used as a cathode electrode, and the ability of air injection into its center to produce H2O2 was investigated. A graphite anode electrode equipped with iron rings was used to increase the electrochemical reaction surface and produce iron ions. The effect of current density, time, and electrolyte concentration on AMX removal efficiency was evaluated by Box-Behnken design method. Subsequently, the effect of AMX concentration variable and pH on removal efficiency was investigated. Finally, the chemical oxygen demand (COD) removal efficiency, toxicity, and effluent activity from the PEF reactor were investigated. The results showed that the modified photoelectro-Fenton process could have efficiency of 99% to remove AMX, in 20 min using current density of 36 mA/cm2 and 16 mM/L electrolyte concentration. Reducing pH and AMX concentration increased the removal efficiency. The PEF process can completely remove the COD in 58 min. Also, toxicity studies indicated an effective reduction in the effluent. This modified reactor improves the efficiency of the PEF process, which, in addition to the 99% removal of AMX, provides a proper function for COD removal, reducing the toxicity properties of the effluent