Efficient removal of aromatic pollutants via catalytic wet peroxide oxidation over synthetic anisotropic ilmenite/carbon nanocomposites
Sheng Guo, Ran Huang, Yuan Jia, Rong Chen, Fengxi Chen
Abstract
Abstract As one of the most common ferrous (Fe 2+ )-containing oxide minerals in the Earth’s crust, ilmenite (FeTiO 3 ) is a potential low-cost heterogeneous Fenton-like catalyst for organic wastewater treatment via catalytic wet peroxide oxidation (CWPO). However, it suffers from low activity and long induction time. Herein anisotropic FeTiO 3 /C nanocomposite with rich Fe 2+ ions on large surface area of 159.0 m 2 g −1 (surface Fe/Ti and Fe 2+ /Fe 3+ ratios were respectively 2.1 and 2.0) was prepared via cetyltrimethylammonium (CTA + )-assisted sol-gel synthesis. CTA + modulated the growth of FeTiO 3 nanoparticles with more exposed metallic sites by preferential adsorption on its (104) plane via electrostatic attraction, provided the carbon source and facilitated the generation of more Fe 2+ ions at the interface of FeTiO 3 /C via carbothermal reduction of FeTiO 3 . FeTiO 3 /C efficiently catalyzed CWPO removal of six aromatic pollutants with different charges (25 mg L −1 each) at 25 o C and pH 3.0 without an induction period owing to rich Fe 2+ content on neutral surface (pH pzc ~3.3)—three dye solutions completely decolorized in 1 h and three antibiotics degraded by >90% in 3 h. Reusability of FeTiO 3 /C was demonstrated with cationic rhodamine B and anionic orange G dyes in five consecutive runs. Scavenging tests and spin-trapping EPR spectra confirmed the generation of dominant ·OH and minor O 2 •− species for organic degradation via catalytic decomposition of H 2 O 2 on FeTiO 3 /C as a heterogeneous Fenton-like catalyst.