Sol-gel Syntheses of Photocatalysts for the Removal of Pharmaceutical Products in Water

Artium Belet,Nathalie Gillard,Stéphanie Lambert,Christelle Vreuls,Dirk Poelman,Julien Mahy,Cédric Wolfs

doi:10.3390/nano9010126

Artium Belet, Nathalie Gillard + Show 5 more

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https://doi.org/10.3390/nano9010126

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Abstract

A screening study on seven photocatalysts was performed to identify the best candidate for pharmaceutical products degradation in water. Photocatalysts were deposited as thin films through a sol-gel process and subsequent dip-coating on glass slides. The efficiency of each photocatalyst was assessed through the degradation of methylene blue first, and then, through the degradation of 15 different pharmaceutical products. Two main types of synthesis methods were considered: aqueous syntheses, where the reaction takes place in water, and organic syntheses, where reactions take place in an organic solvent and only a stoichiometric amount of water is added to the reaction medium. Photocatalysts synthesized via aqueous sol-gel routes showed relatively lower degradation efficiencies; however, the organic route required a calcination step at high temperature to form the photoactive crystalline phase, while the aqueous route did not. The best performances for the degradation of pharmaceuticals arose when Evonik P25 and silver nanoparticles were added to TiO2, which was synthesized using an organic solvent. In the case of methylene blue degradation, TiO2 modified with Evonik P25 and TiO2 doped with MnO2 nanoparticles were the two best candidates.

Highlights

In recent years, concerns about hazards of pharmaceutical compounds found in treated wastewaters, surface water, ground water and drinking water have risen
Endocrine-disruptive chemicals (EDCs) induce failures of the endocrine system in living organisms, leading to perturbations of their growth, physiology, and reproductive tract [1,2,3,4]. Another disastrous effect of the continual exposure to endocrine-disruptive chemicals (EDCs) is the high spread of multidrug-resistant bacteria, especially antibiotics-resistant bacteria [5,6,7,8]
As a consequence of the anthropogenic activities in urban households and clinical environments, effluents coming from wastewater treatment plants (WWTPs) are polluted with pharmaceuticals in a range from ng/L to μg/L

Summary

Introduction

Concerns about hazards of pharmaceutical compounds found in treated wastewaters, surface water, ground water and drinking water have risen The impact of such pollutants in the environment has been extensively studied in the literature and has been acknowledged to constitute a health risk for humans and ecosystems. As a consequence of the anthropogenic activities in urban households and clinical environments, effluents coming from wastewater treatment plants (WWTPs) are polluted with pharmaceuticals in a range from ng/L to μg/L It is well-established that traditional primary, secondary and tertiary physical, chemical and biological treatments in a WWTP do not allow to completely remove complex organic compounds that end up in effluents and sludges. There is a real need for an additional efficient treatment process to degrade these pharmaceuticals before they reach the ecosystem

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