Effective degradation of amoxicillin by multi-stage flow-through electrochemical system using porous electrodes

In this work, an electrooxidation (EO) of amoxicillin (AMX) wastewater treatment was performed based on a three-stage electrochemical flow-through mode to address the emerging issue of antibiotic contaminants in water matrices. The removal of 96.1 % for AMX was obtained and followed pseudo-first-order reaction kinetics (kobs) with a value of 0.1197 min−1 and electric energy per order (EE/O) of 20.47 kWh/m3 at a current density of 8.49 mA/cm2. Compared with single-stage EFTM, the three-stage EFTM had an outstanding performance with a slight difference for AMX degradation and a significantly reduced EE/O. However, a marked difference was achieved in mineralization efficiency. It obtained TOC removal of 81.3 %, which was improved about 1.52 times that of the single-stage EFTM (53.5 %) when an analogous current was applied (500 mA) and reduced 1.77 times concerning the specific energy consumption (EC) of TOC mass removed (3.337 kWh/g TOC). It was moreover astonished that the EC per unit TOC mass removed decreased by increasing an initial quantity of TOC mass. More interestingly, the electrocatalytic of porous Ti–ENTA/SnO2–Sb benefited the production of OH in a three-stage EFTM at high current, which contributes a vital role in removing organic pollutants. Furthermore, scavenging experiments revealed that SO4− radical plays a dominant role as the main radical species compared to OH radical in indirect electrooxidation of AMX. As such, the results of this study indicate that both hydroxyl and sulfate radicals-mediated oxidation. Furthermore, the feasibility and stability of the porous Ti-ENTA/SnO2-Sb anode were evidenced by the practical application potential of a multi-stage flow-through system through its significant and stable AMX removal efficiency of at least 94.2 % during the long-term EO test of 12 h. Hence, the three-stage flow-through system furnishes the superiority with insight and application into the effective treatment of antibiotic wastewater.