Optimized synthesis of Bi4NbO8Cl perovskite nanosheets for enhanced visible light assisted photocatalytic degradation of tetracycline antibiotics

Abstract

A novel 3D architecture of perovskite Bi4NbO8Cl (BNOC) nanosheet was synthesized by molten salt flux method and was employed in the photocatalytic degradation of tetracycline hydrochloride (TCH) and oxytetracycline (OTC), under visible Light Emitting Diode (LED) irradiation. A multivariate approach using response surface methodology (RSM) coupled with face-centered central composite design was performed to model and optimize the synthesis process parameters (solute concentration, temperature, and duration of calcination) targeting the enhancement of degradation efficiency. The significant role of these parameters in the present study was exhibited from the wide variation of degradation efficiencies ranging from 28.53 to 80.12 % for OTC and from 25.46 to 78.36 % for TCH, respectively. The physicochemical properties of BNOC prepared at various synthesis conditions were explored using XRD, FESEM, BET, FTIR, DRS, and PL spectroscopy to delineate the influence of several conditions of the preparation process. A pronounced variation in the crystal structures, morphologies, surface area, and optical properties of the photocatalysts further confirmed the significant influence of synthesis process condition. The maximum degradation of OTC and TCH was 82.07 % and 79.28 %, respectively, when the optimum values of calcination temperature, duration, and solute concentration were 500.1 °C, 10.44 h, and 1.3 mol %, respectively. The catalyst efficiently mineralized 30.4 % OTC in 60 min and was also stable up to four cycles of degradation experiments. Despite having a wide bandgap, the visible light response shown by the BNOC nanosheet photocatalyst evoked its promising future in the field of photocatalysis.