Magnetic LDH-based CoO NiFe2O4 catalyst with enhanced performance and recyclability for efficient decolorization of azo dye via Fenton-like reactions

Magnetic CoO-NiFe2O4 catalyst was successfully fabricated from layered double hydroxide through a simple co-precipitation and calcination method, and for the first time applied as a novel Fenton-like catalyst for the decolorization of Eriochrome black T dye (EB). The characteristics results demonstrated that CoO-NiFe2O4 exhibits a broad pore size distribution in the range of 5-40 nm, large specific surface area (363.6 m(-2) g(-1)) with the high structural stability and saturation magnetization (83.2 emu g(-1)), hence, can be easily recycled for five subsequent runs without significant activity loss. The catalytic activity of CoO-NiFe2O4 was systematically evaluated under varying reaction conditions including initial pH, catalyst dosage, initial dye and H2O2 concentrations. Under the optimal conditions, the CoO-NiFe2O4 accomplished similar to 87-97% decolorization of EB within 120 min. Here, the possible catalytic mechanism for EB decolorization is proposed and concluded to be multi process induced by 'OH, 'O-2(-) or h(+) in the Fenton-like system.