Non-covalent self-assembly synthesis of AQ2S@rGO nanocomposite for the degradation of sulfadiazine under solar irradiation: The indispensable effect of chloride

In this study, the effect of chloride ion (Cl − ) on the degradation of sulfadiazine (SDZ) was evaluated using reduced graphene oxide (rGO) modified with sodium anthraquinone-2-sulfonate (AQ2S) photocatalyst ( [email protected] ), which was prepared in a one-pot hydrothermal synthesis. AQ2S molecules are small organic photoactive components, that are intercalated and immobilized on the rGO surface through noncovalent π-π stacking. Under solar light, SDZ effectively underwent 99 % photodegradation within 150 min in a Cl − -rich solution (0.5 mol/L). The [email protected] system exhibited an excellent photocatalytic removal ability for some typical contaminants. SDZ degradation was driven by 3 AQ2S*. Superoxide radicals ( O 2 − ) and dichlorine radicals (Cl 2 − ) were found to be the dominant reactive species, whereas OH and 1 O 2 have minor roles. Density functional theory (DFT) calculations confirmed the interactions between AQ2S and rGO, and the electronic structural characteristics between Cl − and [email protected] The [email protected] composite has great potential for use in treating micropollutants under saline water conditions under solar irradiation.