Antibiotics mineralization by electrochemical and UV-based hybrid processes: evaluation of the synergistic effect

Abstract

Antibiotics are not efficiently removed in conventional wastewater treatments. In fact, different advanced oxidation process (AOPs), including ozone, peroxide, UV radiation, among others, are being investigated in the elimination of microcontaminants. Most of AOPs proved to be efficient on the degradation of antibiotics, but the mineralization is on the one hand not evaluated or on the other hand not high. At this work, the UV-based hybrid process, namely Photo-assisted electrochemical oxidation (PEO), was applied, aiming the mineralization of microcontaminants such as the antibiotics Amoxicillin (AMX), Norfloxacin (NOR) and Azithromycin (AZI). The influence of the individual contributions of electrochemical oxidation (EO) and the UV-base processes on the hybrid process (PEO) was analysed. Results showed that AMX and NOR presented higher mineralization rate under direct photolysis than AZI due to the high absorption of UV radiation. For the EO processes, a low mineralization was found for all antibiotics, what was associated to a mass-transport limitation related to the low concentration of contaminants (200 µg/L). Besides that, an increase in mineralization was found, when heterogeneous photocatalysis and EO are compared, due to the influence of UV radiation, which overcomes the mass-transport limitations. Although the UV-based processes control the reaction pathway that leads to mineralization, the best results to mineralize the antibiotics were achieved by PEO hybrid process. This can be explained by the synergistic effect of the processes that constitute them. A higher mineralization was achieved, which is an important and useful finding to avoid the discharge of microcontaminants in the environment.

Recent advances in electrocatalysts for halogenated organic pollutant degradation

“…224 The coupling can upgrade the overall degradation performance toward HOPs due to the synergy between different sophisticated processes. 224,225 Fenton reaction, 87,226 membrane filtration, 227,228 biological treatment, 225,229 photocatalysis, 230,231 ozonation, 225,232 adsorption, 225,233 ultrasound, 230,234 UV irradiation, 230,235 microwave, 236 and thermolysis 237,238 are the widely reported methods that can assist the electrochemical activity of electrocatalysis. In this part of the review, the first four methods are detailed due to their wide applications.…”

“…246 In the last few years, photocatalysis has shown to enhance the degradation efficiency of electrocatalysis. 231,[247][248][249] Generally, the following points can explain the synergistic effect.…”

“…On the other hand, the photo irradiation can activate the electrochemically generated reactive radicals and overcome the mass-transport limitation. 249 To mineralize the norfloxacin in wastewater, Salatiel and co-authors 231 found that the ultraviolet radiation could significantly improve the degradation performance of electrochemical oxidation. The coupling strategy possessed a higher TOC abatement (76%) than the direct photolysis (60%) and the electrochemical oxidation process (26%) in 360 min.…”

Effect of the CuO addition on a Sb-doped SnO2 ceramic electrode applied to the removal of Norfloxacin in chloride media by electro-oxidation

“…SM-1, is widely used in veterinary and human medicine against gram-positive and gram-negative bacteria Huang et al, 2008;Mora-Gómez et al, 2019). The presence of antibiotics in the different water bodies, represents a public health risk as they not only develop and increase bacteria resistance to the antibiotic action, but also may cause specific damage to human health (Jojoa-Sierra et al, 2017;Ma et al, 2018;Mora-Gómez et al, 2019;Wohlmuth da Silva et al, 2018).…”

WITHDRAWN: Reuse of Waste Materials as Precursors of Activated Carbon Synthesis for the Abatement of Antibiotic Cefpodoxime Proxetil from Industrial Effluents.

“…Industries have acquired a broad range of techniques and methods such as catalytic ozonation, bio-remediation, photocatalytic oxidation, coagulation and biological handlings for elimination of antibiotics from industrial wastewater treatment plants [6,7]. Although, these advance technological processes are well serviceable for industries to complete mineralization and conversion of antibiotic molecules to simpler ones, but these are relatively high in cost and laborious to maintain on industrial scale for efficient removal [8].…”