Highly efficient photodegradation of magnetic GO-Fe 3 O 4 @SiO 2 @CdS for phenanthrene and pyrene: Mechanism insight and application assessment.

A novel magnetic core-shell Fe3 O4 @SiO2 @CdS embedded graphene oxide (GO) composite was prepared for the visible-light-driven photodegradation of high ring number polycyclic aromatic hydrocarbons (PAHs). The potential application of GO-Fe3 O4 @SiO2 @CdS was evaluated through the photodegradation of phenanthrene and pyrene in deionized water, tap water, and lake water, respectively. It was found that GO-Fe3 O4 @SiO2 @CdS could remove 86.4 % of phenanthrene and 93.4 % of pyrene, suggesting its potential for the degradation of high-ring number PAHs. The density functional theory (DFT) calculations demonstrate that pyrene has more active sites attacked by free radicals. The photoelectrochemical measurement and quenching experiments indicate that GO can transfer photoelectrons efficiently, resulting in the crucial radicals (O2 - , OH and 1 O2 ). More importantly, the photocatalytic activity kept almost constant during five cycles, confirming the significant anti-photocorrosion of GO-Fe3 O4 @SiO2 @CdS. This work provides some new insights into the removal of PAHs with high-ring numbers in the natural water environment.