Visible Light Assisted Heterogeneous Fenton-Like Degradation of Organic Pollutant via α-FeOOH/Mesoporous Carbon Composites

A novel alpha-FeOOH/mesoporous carbon (alpha-FeOOH/MesoC) composite prepared by in situ crystallization of adsorbed ferric ions within carboxyl functionalized mesoporous carbon was developed as a novel visible light assisted heterogeneous Fenton-like catalyst. The visible light active alpha-FeOOH nanocrystals were encapsulated in the mesoporous frameworks accompanying with surface attached large alpha-FeOOH microcrystals via C-O-Fe bonding. Assisting with visible light irradiation on alpha-FeOOH/MesoC, the mineralization efficiency increased owing to the photocatalytic promoted catalyzing H2O2 beyond the photothermal effect. The synergistic effect between alpha-FeOOH and MesoC in alpha-FeOOH/MesoC composite improved the mineralization efficiency than the mixture catalyst of alpha-FeOOH and MesoC. The iron leaching is greatly suppressed on the alpha-FeOOH/MesoC composite. Interestingly, the reused alpha-FeOOH/MesoC composites showed much higher phenol oxidation and mineralization efficiencies than the fresh catalyst and homogeneous Fenton system (FeSO4/H2O2). The XPS, XRD, FTIR, and textural property results reveal that the great enhancement comes from the interfacial emerged oxygen containing groups between alpha-FeOOH and MesoC after the first heterogeneous Fenton-like reaction. In summary, visible light induced photocatalysis assisted heterogeneous Fenton-like process in the alpha-FeOOH/MesoC composite system improved the HO center dot production efficiency and Fe(III)/Fe(II) cycle and further activated the interfacial catalytic sites, which finally realize an extraordinary higher degradation and mineralization efficiency.