Enhanced Fenton-like degradation of Rhodamine B and Congo red by benzene and K+ co-doped carbon nitride with in situ-generated H2O2

Fe2+/H2O2-based photo-Fenton process is often used in pollutions removal. But, Fe-species related low activity at neutral condition hinders their practical applications. Activation of in situ generated H2O2 for Fenton-like degradation of pollutions through catalysts absences of Fe species is expected. A strip-like benzene and K+ co-doped g-C3N4 (KBCN) was constructed by the thermal polymerization of assembly of melamine and 2-aminoterephthalic acid, then post-calcination in LiCl–KCl molten salt, which was then used to degrade Rhodamine B (RhB) and Congo red (CR) via in situ generated H2O2. Benzene and K+ co-doping were critical both in increasing charge separation and enhancing the H2O2 production. The yield of H2O2 for KBCN was 57.5 μM in pure water after 60 min irradiation. In the absence of Fe2+, the in situ generated H2O2 could subsequently degrade RhB and CR with the formed ·OH. The apparent rate constants of KBCN for RhB and CR degradation were 0.0446 and 0.0497 min−1, respectively. The advantages of degradation with in situ generated H2O2 in the absence of Fe2+ can provide a new prospective to the environmental friendly Fenton-like reaction.