Enhanced visible-light activation of persulfate for the removal of RhB by supported nano-(C,N,B)-tridoped TiO2/copper foam mixed-crystals.

Abstract

Photocatalytic persulfate activation by TiO2 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 TiO2 limited its practical application. Herein, by using C-, N-, and B-modified TiO2 and immobilizing it on copper foam, we prepared a new and efficient (C,N,B)-TiO2/copper foam photocatalyst with enhanced visible-light activation performance of persulfate for the removal of RhB. It almost completely degraded RhB within 15min of UV-vis light photocatalysis-assisted persulfate oxidation reaction with TOC removal of 53.17% in 30min 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)-TiO2/copper foam exhibited the largest apparent rate constant (0.149min-1), 1.16 times higher than (C,N,B)-TiO2 (0.128min-1), and 2.40 times higher than that of TiO2 (0.062min-1), respectively. C,N,B doping modified the crystalline phase of TiO2, 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 TiO2. The 1O2 was the primary oxidation active species for the degradation of RhB, and the radical species (SO4•-, •O2-, and •OH) could further accelerate the photocatalytic activation of persulfate reaction.