Degradation of chloramphenicol by potassium ferrate (VI) oxidation: kinetics and products

Abstract

The oxidation of chloramphenicol (CAP) by potassium ferrate (VI) in test solution was studied in this paper. A series of jar tests were performed at bench scale with pH of 5-9 and molar ratio [VI/CAP] of 16.3:1-81.6:1. Results showed that raising VI dose could improve the treatment performance and the influence of solution pH was significant. VI is more reactive in neutral conditions, presenting the highest removal efficiency of CAP. The rate law for the oxidation of CAP by VI was first order with respect to each reactant, yielding an overall second-order reaction. Furthermore, five oxidation products were observed during CAP oxidation by VI. Results revealed that VI attacked the amide group of CAP, leading to the cleavage of the group, while benzene ring remained intact.

Ferrate (VI) Oxidation Is an Effective and Safe Way to Degrade Residual Colistin - a Last Resort Antibiotic - in Wastewater

“…Analysis of variance indicated that colistin degradation at pH 7 was significantly greater than those at all other pH values we examined (P < 0.05) and that at pH 10 was significantly lower than those at other pH values (P < 0.05; Table 3). Similar results were obtained when Fe (VI) was used to oxidize chloramphenicol (50). The initial pH of the solution most likely influences not only Fe (VI) stability which decreases as the pH declines, but also the oxidation capacity of Fe (VI) that decreases at elevated pH.…”

“…Although Fe (VI) is stable under alkaline conditions, its low redox potential (0.7 V) restricts the reaction and colistin removal. Under acidic conditions, although Fe (VI) shows a high redox potential (2.2 V), its self-decomposition hindered the colistin reaction and Fe (VI) self-decay occurred rapidly within minutes at pH < 6.0 (50,51). Therefore, extremes of pH were not conducive to colistin removal and we selected pH 7.0 as the optimal initial pH for further study.…”