Degradation of Bisphenol A and Pyrocatechol in the Photocatalytic System in the Presence of Fe3O4@SiO2@PAEDTC-Doped MIL-101 (Fe) Under Visible and UV and Sunlight Irradiation

Abstract

In this investigation, a novel core-shell photocatalyst, denoted as Fe₃O₄@SiO₂/PAEDTC (FSP)-doped MIL-101 (Fe) (FSPM), was synthesized through the sol–gel method and applied for the degradation of bisphenol A (BPA) and pyrocatechol (PCT) in aqueous solutions. Various analytical techniques were employed to assess the characteristics of the core-shell photocatalyst. The resultant nanocomposite displayed specific attributes, including a saturation magnetization of 12 emu/g, a pore size of 1.35 nm, and a surface area of 992 m²/g, allowing for facile separation using a magnetic field. The optimal conditions for achieving highest BPA (%94.2) and PCT (%100) degradation efficiencies were found to be a pH of 7, 50 mg/L pollutant, a nanocomposite quantity of 0.8 g/L, and a radiation intensity of 8 W after 1 h. The BOD₅/COD (biological oxygen demand during 5 days/chemical oxygen demand) ratio exceeded 0.4, accompanied by total organic carbon (TOC) and COD removal rates surpassing 85%. The tests conducted on scavenging suggested the formation of ^•OH, hole, and electron in the studied system. Among these, ^•OH was found to be the foremost species responsible for degrading BPA and PCT. Stability tests revealed that the photocatalyst could be recycled with a minimal reduction of only 7% during five reaction steps. The energy consumed by the system during different reactions ranged from 10.2 to 27.1 kWh/m³ for BPA degradation and from 10.9 to 29.4 kWh/m³ for PCT degradation at time of 10 to 60 min. Finally, the results of this study showed that the use of all three sources of radiation in the photocatalytic process can effectively destroy pollutants.