Oxidative Degradation of Amoxicillin in Aqueous Solution by Thermally Activated Persulfate

Juanjuan Zhao,Fachao Wu,Yujiao Sun,Minjian Shi,Xurui Liu

doi:10.1155/2019/2505823

Abstract

Antibiotic residues and antibiotic resistance genes (ARGs) pose a great threat to public health and food security via the horizontal transfer in the food production chain. Oxidative degradation of amoxicillin (AMO) in aqueous solution by thermally activated persulfate (TAP) was investigated. The AMO degradation followed a pseudo-first-order kinetic model at all tested conditions. The pseudo-first-order rate constants of AMO degradation well-fitted the Arrhenius equation when the reaction temperature ranged from 35°C to 60°C, with the apparent activate energy of 126.9 kJ·mol−1. High reaction temperature, high initial persulfate concentration, low pH, high Cl− concentration, and humic acid (HA) concentration increased the AMO degradation efficiency. The EPR test demonstrated that both ·OH and SO4·− were generated in the TAP system, and the radical scavenging test identified that the predominant reactive radical species were SO4·− in aqueous solution without adjusting the solution pH. In groundwater and drinking water, AMO degradation suggested that TAP could be a reliable technology for water remediation contaminated by AMO in practice.

Highlights

Antibiotic residues ubiquitously exist in surface water, groundwater, and soil because of overuse and misuse in human and veterinary medicines, leading to the prevalence of antibiotic resistance genes (ARGs) in natural environment [1]
ARGs as a kind of emerging contaminants pose a great threat to public health and food security mainly due to the persistence in environment and the horizontal transfer in the food production chain [2, 3]. us, it is urgent to take effective measures to eliminate the antibiotics in natural environment in order to reduce the influence of ARGs
Reaction temperature is a critical factor that should be considered for applying TAP to degrade organic contaminants

Summary

Introduction

Antibiotic residues ubiquitously exist in surface water, groundwater, and soil because of overuse and misuse in human and veterinary medicines, leading to the prevalence of antibiotic resistance genes (ARGs) in natural environment [1]. Sulfate radicals could be generated through scission of the peroxide bond of persulfate by energy including heat [8, 9], ultraviolet [5, 10], ultrasound [11], radiolysis [12], and catalyzer [13,14,15,16]. Among these methods, TAP is attractive for removing organic contaminants because it is a simple and effective method to produce sulfate radicals with a high reaction stoichiometric efficiency (RSE) [17]. E aim of this present study was to investigate TAP for the remediation of highly AMO-contaminated water, including the influence factors of the reaction temperature, initial PS concentration, pH and Cl−, Ca2+, Mg2+, humic acid (HA), and dissolved oxygen. e predominant radicals were identified by electron paramagnetic resonance (EPR), and AMO degradation in real waters was evaluated, which provides fundamental and practical knowledge to treat AMO-contaminated waters

Materials and Methods

Results and Discussion

Effects of Matrix in Aqueous Solution on Degradation of AMO

Conclusions