Photocatalytic Degradation of Valsartan by MoS2/BiOCl Heterojunctions

Eleni Grilla,Zacharias Frontistis,Dionissios Mantzavinos,Maria Nefeli Kagialari,Athanasia Petala

doi:10.3390/catal11060650

Eleni Grilla, Zacharias Frontistis + Show 3 more

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https://doi.org/10.3390/catal11060650

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Abstract

In the present study, the removal of valsartan (VLS), an antihypertensive agent, under simulated solar radiation with the use of molybdenum sulfide-bismuth oxychloride composites (MoS2/BiOCl), of variable MoS2 content (0.1–10.0 wt.%) was investigated. The physicochemical properties of the photocatalysts were examined by XRD, DRS, BET and TEM/HRTEM. Preliminary tests were conducted to examine the photocatalytic efficiency of the synthesized MoS2/BiOCl composites towards VLS degradation in ultrapure water (UPW). It was found that the activity of pure BiOCl is improved with the addition of MoS2. The degradation rate was maximized with the use of the catalyst containing 0.25 wt.% MoS2. It was also found that the increase in catalyst concentration (50–1000 mg/L) enhances VLS degradation. It was found that VLS removal decreased by increasing VLS concentration. The effect of the water matrix on VLS removal was studied by carrying out experiments in real and synthetic water matrices. VLS degradation in UPW was faster than in bottled water (BW) and wastewater (WW), mainly due to the existence of organic matter in real aqueous media. Lastly, 0.25 wt.% MoS2/BiOCl showed great stability after 360 min of irradiation, serving as a promising catalyst for water remediation of emerging contaminants under solar irradiation.

Highlights

The ubiquity of pharmaceutically active compounds (PhACs) in aqueous media is one the biggest topics of concern for the 21st century [1,2,3]
20% of the dose is recovered as metabolites, so the recovery is more as an unchanged compound [6]
The primary crystallize size of the synthesized photocatalysts are shown on Table 1

Summary

Introduction

The ubiquity of pharmaceutically active compounds (PhACs) in aqueous media is one the biggest topics of concern for the 21st century [1,2,3]. PhACs mainly end up in waters through direct uncontrolled discharge from hospitals, households and industries, as well as through excretion from humans and animals’ faeces or urine [2,3]. VLS is mainly recovered in faeces and urine when given as an oral solution. There have been reports of its presence in wastewater treatment plants all over the world, at concentrations between 11 ng/L and 6 μg/L [7,8,9,10]. These levels prove VLS minor degradation by conventional wastewater treatments plants. Alternative treatments need to be developed to remove VLS from waters

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