Preparation of a novel clay loaded with Fe (VI) for degradation of cefazolin: performance, pathway, and mechanism.

Mingluo Zhou,Yi Zhou,Shu Chen,Riyu Zhou,Weiguo Tu,Haiyan Chen,Peng Jiang,Yuankun Yang,Bin Wang,Huili Liang

doi:10.1007/s11356-022-18636-x

Abstract

Cephalosporin antibiotics, a group of widely prescribed antibiotics, are frequently detected in wastewater effluent and in the natural aquatic environment. Materials have been sought to effectively degrade the antibiotics. In this study, a novel high-iron clay was prepared with potassium ferrate and montmorillonite via a strong alkaline in situ synthesis method. Degradation of cefazolin sodium (CFZ) by this novel Fe (VI)-clay was investigated. The optimal conditions for the degradation of CFZ were determined using a single factor experiment and response surface optimization method. We found that 89.84% removal efficiency was obtained in 137min when pH value was 5.16 and Fe (VI)-clay dosage was 0.79g. The CFZ degradation mechanism was studied by computations on the Frontier Electron Density (FED) in combination with spectroscopic and mass spectroscopic analysis. The spectroscopic characteristics of the products at different stages showed that the oxidation decomposition reaction occurred during the degradation of CFZ by Fe (VI)-clay. Furthermore, FED calculation combined with GC-MS results showed that the degradation pathways of CFZ by the Fe (VI)-clay was mainly the cleavage of β-lactam, thiadiazole, tetrazole, and dihydrothiazine rings.

Highlights

Antibiotics play a vital role in the treatment of human infectious diseases and in the prevention and treatment of animal diseases to improve breeding efficiency (Lu et al 2018; Qu et al 2019)
The absorption peak at 1638 cm−1 corresponded to Si-O-Si skeleton vibration, whereas the broad and intense peak at 1035 cm−1 corresponded to the stretching vibration peak of Si-O-Si
In Fe (VI)-clay, the characteristic peak changed from a sharp peak to weak and strong absorption broadband, which may be due to the spatial steric hindrance effect that forces the bond angle between adjacent groups to change, resulting in the deviation of the vibration band and the shift of the absorption peak to about 1404 cm−1

Summary

Introduction

Antibiotics play a vital role in the treatment of human infectious diseases and in the prevention and treatment of animal diseases to improve breeding efficiency (Lu et al 2018; Qu et al 2019). The degradation characteristics of CFZ by high iron clay were investigated. The optimal conditions were determined by single factor experiment and response surface optimization method, and the degradation mechanism of CFZ by high iron clay was investigated.

Results

Conclusion