An efficient graphene supported copper salen catalyst for the activation of persulfate to remove chlorophenols in aqueous solution

Schiff base metal complexes are effective homogeneous catalysts used in oxidation reactions in organic synthesis. However, application of these catalysts in aqueous solution is limited by their effectiveness and stability. In this study, a novel graphene based Schiff base copper complex (Cu(salen)) was developed to effectively activate persulfate (PS) for the removal of organic pollutants in aqueous solution. Aminated reduced graphene oxide (ArGO) was used as a carrier of the heterogeneous catalyst, DArGO-Cu, which was synthesized by the condensation reaction of 3, 5-dibromosalicylaldehyde with ArGO followed by the complexing reaction with copper acetate monohydrate. The surface structure and morphology as well as elemental composition of DArGO-Cu were characterized by SEM, TEM, XPS, FTIR, Raman and elemental analysis. The catalytic performance of DArGO-Cu to activate PS was evaluated with the degradation of triclosan (TCS) in water at room temperature. The mechanism for DArGO-Cu to activate PS was the generation of SO4 center dot- which was immediately converted to (OH)-O-center dot to degrade TCS. The role of graphene played in catalysis was not only as a carrier for Cu(salen) but also to build hydrophobic microdomains for the stabilization of the catalytic active sites in the reaction.