Enhanced visible light driven photoelectrochemical degradation of tetracycline hydrochloride using a BiOI photoanode modified with MnO2 films.

Abstract

Removal of pharmaceuticals in wastewater has been the focus of many research due to the recalcitrant nature and hazardous effects of these compounds. The photoelectrochemical degradation process has proven to be suitable to harness solar energy for the mineralization of organic compounds in wastewater. Herein, we report the application of BiOI/MnO2 heterostructured anode for the photoelectrochemical degradation of tetracycline hydrochloride in aqueous solution. The photoanode was prepared through electrodeposition technique and fully characterized through microscopic, spectroscopic and electrochemical techniques. The results showed that formation of p-n heterojunction between BiOI and MnO2 in the photoanode led to improved charge separation which was evident in improved optical and photoelectrochemical properties. The FTO-BiOI/MnO2 electrode attained a photocurrent density of 0.104mAcm-2 with applied potential of 1.0V (vs Ag/AgCl) which was almost double that of pristine BiOI suggesting efficient charge separation. The heterostructured photoanode achieved 94% removal of tetracycline hydrochloride after 120min through the PEC degradation process with 61% mineralization efficiency. The electrode showed good reusability and stability with 92% PEC removal after eight cycles. Hence, the FTO-BiOI/MnO2 has a great potential as anode for PEC wastewater treatments.