The preparation of δ-FeOOH/γ-Al2O3 under mild conditions as an efficient heterogeneous Fenton catalyst for organic pollutants degradation

Abstract

The δ-FeOOH/γ-Al2O3 composite were prepared under mild conditions by the activated alumina absorption of Fe2+ followed by rapid oxidation by H2O2. The δ-FeOOH growing on γ-Al2O3 was composed of nanoneedles, forming a 3D flower-like morphology with a diameter of ~10 nm to provide a large number of active sites. The effects of Fenton reaction conditions, such as catalyst dosage, H2O2 concentration, phenol concentration, initial pH value and temperature, on the catalytic activity of δ-FeOOH/γ-Al2O3 were investigated. Under the optimal conditions, about 97.4% of phenol and 81.6% of total organic carbon (TOC) were removed in 5 min and 2 h, respectively. In addition, with γ-Al2O3 as macroscopic size carrier (the diameter of 1–2 mm), the catalyst could be easily reused 10 runs with no significant reduction in catalytic activity. The possible mechanism was discussed, and it revealed that OH· was the main active species for degradation of phenol into intermediates and further into CO2 and H2O. The δ-FeOOH/γ-Al2O3 also showed high catalytic activity and reusability in the treatment of real industrial wastewater, making it a promising catalyst for industrial application.