Acute Photocatalytic Oxidation of Tetracycline by Novel Ag3PO4/BiPO4/Hydroxyapatite Heterojunction

Abstract

We present the first-ever synthesis of the Ag3PO4/BiPO4/HAp nanocomposite, a phosphate-based heterojunction, for visible-light-driven photocatalysis application. The photocatalyst was synthesized via a facile hydrothermal method and comprehensively characterized through different techniques including XRD, SEM-EDS, BET-SA, DRS, XPS, PL, and photoelectrochemical analysis (Mott – Schottky, transient photocurrent and EIS analysis). The photocatalytic activity of the as-prepared novel nanocomposite was scrutinized for the degradation of non-biodegradable pharmaceutical waste, i.e. Tetracycline (TC), under visible light irradiation of 165W. The novel Ag3PO4/BiPO4/HAp nanocomposite catalyst exhibited synergistic results as it revealed much higher photocatalytic degradation efficiency (90%) than the Ag3PO4/BiPO4 (70%) and the individual catalysts, i.e. Ag3PO4 (60%), BiPO4 (10%) and HAp (0%), under the same irradiation conditions. The augmented rate of photocatalytic efficiency of the nanocomposite could be ascribed to the high visible light absorption capacity of Ag3PO4/BiPO4/HAp and significantly reduced charge carrier recombination through both the heterojunction of Ag3PO4/BiPO4 and presence of HAp in the composite. The latter, thus, offering high surface area and enhanced adsorption which promotes the mass transfer in heterogeneous photocatalysis reaction. The scavenger experiments illustrated that hydroxyl radicals (•OH) were the leading active species in the presented photocatalytic process.