Enhancing photocatalytic degradation of hydrolyzed polyacrylamide in oilfield wastewater using BiVO4/TiO2 heterostructure nano-photocatalyst under visible light irradiation

Abstract

The goal of this study was to develop a TiO2 and BiVO4 heterostructure nano-photocatalyst for the photocatalytic treatment of hydrolyzed polyacrylamide (HPAM) in oilfields utilizing visible light irradiation. A straightforward coupling technique was used to create BiVO4/TiO2 heterojunction photocatalysts. Results of SEM, EDS, and XRD studies, as well as the chemical composition identified by XPS, gave proof that the BiVO4/TiO2 nanocomposite was effectively synthesized. The bandgaps of pure BiVO4, TiO2, and 5%, 10%, 15%, 20%, and 50% BiVO4/TiO2 nanocomposites are 2.53 eV, 3.21 eV, 3.03 eV, 2.89 eV, 2.69 eV, 2.64 eV, and 2.58 eV, respectively. According to optical studies, the addition of BiVO4 improved the light harvesting capability, particularly in the visible range. By adding the BiVO4 catalyst to the TiO2 structure, the charge-transfer resistance reduces, indicating enhanced interfacial charge transfer, according to electrochemical impedance spectroscopy. According to photodegradation efficiency, pure BiVO4, TiO2, and nanocomposites made of 5% BiVO4/TiO2, 10% BiVO4/TiO2, 15% BiVO4/TiO2, and 50% BiVO4/TiO2 all degraded completely after 85, 115, 55, 35, 25, 45, and 50 minutes of exposure to visible light, respectively. Results of a study on the effectiveness of nanocomposites for the photocatalytic degradation of HPAM in wastewater from an oilfield that contains polymers showed that 15% BiVO4/TiO2 nanocomposite can be a good alternative.