Enhanced visible-light activation of persulfate for the removal of RhB by supported nano-(C,N,B)-tridoped TiO/copper foam mixed-crystals.

Photocatalytic persulfate activation by TiO and its application in sewage treatment have aroused great interest because of its high decontamination ability and strong adaptability, but the low light energy utilization rate and poor recycling of TiO limited its practical application. Herein, by using C-, N-, and B-modified TiO and immobilizing it on copper foam, we prepared a new and efficient (C,N,B)-TiO/copper foam photocatalyst with enhanced visible-light activation performance of persulfate for the removal of RhB. It almost completely degraded RhB within 15 min of UV-vis light photocatalysis-assisted persulfate oxidation reaction with TOC removal of 53.17% in 30 min and presented the excellent long-term recyclability and stability, which is much better or comparative than those photocatalysts in the related literatures. (C,N,B)-TiO/copper foam exhibited the largest apparent rate constant (0.149 min), 1.16 times higher than (C,N,B)-TiO (0.128 min), and 2.40 times higher than that of TiO (0.062 min), respectively. C,N,B doping modified the crystalline phase of TiO, narrowed its band gap, and reduced charge-carrier recombination rate. These, together with the synergistic effect between photocatalysis and persulfate activation for enhancing generation of active species, jointly promoted the performance enhancement of TiO. The O was the primary oxidation active species for the degradation of RhB, and the radical species (SO, O, and OH) could further accelerate the photocatalytic activation of persulfate reaction.