Towards visible light driven photoelectrocatalysis for water treatment: Application of a FTO/BiVO4/Ag2S heterojunction anode for the removal of emerging pharmaceutical pollutants

Benjamin O Orimolade,Omotayo A Arotiba

doi:10.1038/s41598-020-62425-w

Benjamin O Orimolade, Omotayo A Arotiba

Open Access

https://doi.org/10.1038/s41598-020-62425-w

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Journal: Scientific Reports	Publication Date: Mar 24, 2020
Citations: 73	License type: open-access

Affiliation: University of Johannesburg

Abstract

Pharmaceuticals have been classified as emerging water pollutants which are recalcitrant in nature. In the quest to find a suitable technique in removing them from contaminated water, photoelectrocatalytic oxidation method has attracted much attention in recent years. This report examined the feasibility of degrading ciprofloxacin and sulfamethoxazole through photoelectrocatalytic oxidation using FTO-BiVO4/Ag2S with p-n heterojunction as anode. BiVO4/Ag2S was prepared through electrodeposition and successive ionic layer adsorption/reaction on FTO glass. Structural and morphological studies using XRD, SEM, EDS and diffusive reflectance UV-Vis confirmed the successful construction of p-n heterojunction of BiVO4/Ag2S. Electrochemical techniques were used to investigate enhanced charge separation in the binary electrode. The FTO-BiVO4/Ag2S electrode exhibited the highest photocurrent response (1.194 mA/cm−2) and longest electron lifetime (0.40 ms) than both pristine BiVO4 and Ag2S electrodes which confirmed the reduction in recombination of charge carriers in the electrode. Upon application of the prepared FTO-BiVO4/Ag2S in photoelectrocatalytic removal of ciprofloxacin and sulfamethoxazole, percentage removal of 80% and 86% were achieved respectively with a low bias potential of 1.2 V (vs Ag/AgCl) within 120 min. The electrode possesses good stability and reusability. The results obtained revealed BiVO4/Ag2S as a suitable photoanode for removing recalcitrant pharmaceutical molecules in water.

Highlights

Water pollution is a global challenge with a lot of negative environmental and health implications
In order to cut down the cost associated with the operation of photoelectrocatalytic degradation process, solar light has been considered as a source of photon energy but this requires that the anodic material be made up of visible light active photocatalyst
We report for the first time the photoelectrocatalytic degradation of pharmaceuticals in water using a p-n heterostructure of BiVO4/Ag2S prepared on FTO glass as anode

Summary

Introduction

Water pollution is a global challenge with a lot of negative environmental and health implications. We report for the first time the photoelectrocatalytic degradation of pharmaceuticals in water using a p-n heterostructure of BiVO4/Ag2S prepared on FTO glass as anode.

Results

Conclusion