RESUMO
In this study, a new core-shell Fe3O4@SiO2/PAEDTC@MIL-101 (Fe) photocatalyst was prepared by sol-gel method and used to degrade diazinon (DZN) and chlorpyrifos (CPS) from aqueous solutions. The characteristics analyzed by various techniques indicate that the core-shell photocatalyst with a specific surface area of 992 m2/g, pore size of 1.35 nm and saturation magnetization of nanocomposite was 12 emu/g has been successfully synthesized and can be separated from the reaction solution by a magnetic field. The maximum efficiencies of DZN (98.8%) and CPS (99.9%) were provided at pH of 5, photocatalyst dosage of 0.6 g/L, pollutant concentration of 25 mg/L, radiation intensity of 15 W, and time of 60 min. The presence of anions such as sulfate, nitrate, bicarbonate, phosphate, and chloride had a negative effect on the performance of the photocatalysis system. Compared to the adsorption and photolysis systems alone, the photocatalytic process based on Fe3O4@SiO2/PAEDTC@MIL-101 (Fe) under two UV and visible light sources showed a high efficiency of 90% in the reaction time of 60 min. The BOD5/COD ratio improved after 50 min to above 0.4 with TOC and COD removal rates >80%. Scavenging tests showed that â¢OH radical, hole (h+), electron (e-), and O2â¢- anion were produced in the reaction reactor, and the â¢OH radical was the dominant species in the degradation of DZN and CPS. The stability tests confirmed the recyclability of the photocatalyst in 360 min of reactions, with a minimum reduction of 7%. Energy consumption for the present system during different reactions was between 15.61 and 25.06 kWh/m3 for DZN degradation and 10-22.87 kWh/m3 for CPS degradation.