Highly efficient LaFeO3/Bi2WO6 Z-scheme nanocomposite for photodegradation of tetracycline under visible light irradiation: Statistical modeling and optimization of process by CCD-RSM

Abstract

The major problems of the semiconductor nanomaterials in the photocatalytic applications for degradation of organic contaminants are fast recombination of photogenerated electron-hole pairs and low visible light harvesting. Therefore, we tried to resolve these drawbacks by coupling LaFeO3 nanoparticles with Bi2WO6 nanoflakes and constructing of binary Z-scheme heterojunction through the facile solvothermal synthesis approach. The photocatalytic activity of the LaFeO3/Bi2WO6 heterojunction was studied through degradation of tetracycline (TC) upon visible light irradiation. The effects of experimental parameters, including LaFeO3/Bi2WO6 dosage, initial concentration of TC, visible light irradiation time, and solution pH on the photocatalyst performance of binary nanocomposite were analyzed by response surface methodology. The results of analysis of variance confirmed that these parameters have a significant effect on the TC degradation efficiency. The value of the first-order kinetic rate constant for removal of TC using LaFeO3/Bi2WO6 was calculated 0.1291 min−1, which was 20 and 10 times higher than pure LaFeO3 and Bi2WO6, respectively. Besides, LaFeO3/Bi2WO6 was shown the excellent photocatalytic stability after 4 cycles. Furthermore, the photocatalytic pathway for photodegradation of TC by binary LaFeO3/Bi2WO6 nanocomposite was proposed according to the trapping experiments of active species and the results were signify that the h+ and .OH are the predominant reactive species for the photodegradation of TC. Overall, we believe that current novel research opens a promising route for the preparation of highly efficient LaFeO3/Bi2WO6 photocatalyst and its usage for wastewater treatment.