One pot synthesis of CuFeO2 @ expanding perlite as a novel efficient floating catalyst for rapid degradation of methylene blue under visible light illumination

This paper describes a new environmentally friendly and affordable visible light water-floating photocatalyst made from expanded perlite (Ep) decorated with CuFeO2 dellasossite (CuFeO2@Ep). CuFeO2 was directly deposited on the perlite surface trough a facile one-step hydrothermal reaction under moderate condition. The XRD, N-2 adsorption/desorption, FT-IR, SEM, PL and UV-Vis DRS analyses were applied for the study of the structure and optical properties of CuFeO2@Ep photocatalysts. Time induced structural properties were monitored using XRD and optimum reaction time was achieved in 24 h. The crystallographic characterization clearly validated the pure rhombohedral crystal structure of CuFeO2 (3R-CuFeO2) and BET results clarified increasing the surface area and pore volume of CuFeO2@Ep compared to pure CuFeO2. Also, SEM, FT-IR, XRD, BET and EDX results indicated effective loading of CuFeO2 on the surface of the perlite granules. The results showed that CuFeO2 particles with a rhombohedral-like structure were homogenously dispersed on Ep surface. The optimized CuFeO2@Ep displayed the electronic structure and band gap energy of 1.81 eV in the UV-Vis diffraction reflectance spectroscopy (DRS) absorption, exhibiting its efficiency to absorb light in the visible area. The synthesized composite was used as a photocatalyst for degradation of methylene blue (MB) with an efficiency of 99% with optimized mass ratio (1.5:1 of CuFeO2: Ep) under visible light irradiation. Results displayed excellent photocatalytic activity in a very short reaction time (nearly 30 min) compared to the pure CuFeO2 (29%) and Ep (16%). This is because of a synergistic influence between CuFeO2 and Ep as well as the shaping of CuFeO2@Ep plane structure by way of interaction among CuFeO2 and Ep in the moderate hydrothermal reaction. Based on the trapping experiments, O-2(center dot-) as active species with reaction at the surface of photocatalyst play key role in the elimination of MB in the photodegradation Performance. The decrease effect of photocatalytic activity in repeated use was less than 5% over 4 cycles. These results indicated the composite as a good photocatalyst and a probable material for other photocatalytic applications. The excellent visible light photoactivity of introduced catalyst as well as its ability to float, combined with its stability, makes it particular choice for the purification of contaminated water in the lab and industrial scales.