CoMn2O4 Catalyst Prepared Using the Sol-Gel Method for the Activation of Peroxymonosulfate and Degradation of UV Filter 2-Phenylbenzimidazole-5-sulfonic Acid (PBSA).

Chihao Lin,Ping Sun,Jiaqiang Wu,Hui Liu,Zhentao Wu,Ruirui Han,Zhicai Zhai,Dejian Shi,Yingsen Fang,Lingfeng Zhang

doi:10.3390/nano9050774

Abstract

In this study, a bimetallic oxide catalyst of cobalt-manganese (CoMn2O4) was synthesized using the sol-gel method, and it was then characterized using a variety of techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption–desorption isotherms. The obtained novel catalyst, i.e., CoMn2O4, was then used as an activator of peroxymonosulfate (PMS) for the catalytic degradation of a commonly-used UV filter, 2-phenylbenzimidazole-5-sulfonic acid (PBSA) in water. The effects of various factors (e.g., catalyst dosage, PMS concentration, reaction temperature, and pH) in the process were also evaluated. Chemical scavengers and electron paramagnetic resonance (EPR) tests showed that the •OH and SO4•− were the main reactive oxygen species. Furthermore, this study showed that CoMn2O4 is a promising catalyst for activating PMS to degrade the UV filters.

Highlights

In recent years, UV filters have been increasingly used in personal care products (PCPs), such as sunscreen creams, lipsticks, shampoos, and hair gels
Methanol and formic acid were of high-performance liquid chromatography (HPLC) grade obtained from Sigma-Aldrich (Shanghai, China), and other reagents were of an analytical grade and they were obtained from Macklin Biochemical Co., Ltd. (Shanghai, China), including Co(NO3)2·6H2O, Mn(NO3)2·4H2O, citric acid, glycine, humic acid (HA), absolute ethanol (EtOH), and tert-butanol (TBA)
The surface elemental composition of the sample was analyzed by the ESCALAB 250XI X-ray photoelectron spectroscopy (XPS) (Thermo Fisher Scientific, Waltham, MA, USA) using Al K-alpha radiation under conditions optimized for the maximum signal

Summary

Introduction

UV filters have been increasingly used in personal care products (PCPs), such as sunscreen creams, lipsticks, shampoos, and hair gels. Given their dramatically increasing daily use, UV filters are continuously being discharged into the aquatic environment, and have become a class of emerging contaminants (ECs) and formed “false persistent” pollution [1,2]. A large number of studies have shown that some organic UV filters can mimic the effects of various hormones in living organisms, thereby interfering with the normal endocrine functions of animals and humans, resulting in potentially serious health threats [3,4,5,6,7,8]. It is necessary to apply some cost-effective techniques such as advanced oxidation processes (AOPs), to ensure the efficient elimination of such ECs from the water environment [11]

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Conclusion