Synthesis and characterisation of novel beta-cyclodextrin based Fe3O4 nanocomposite: adsorption behaviour and photocatalytic dye degradation studies

Novel Beta-Cyclodextrin-based Fe3O4 nanocomposite has been synthesised through copolymerisation by incorporating Fe3O4 nanoparticles into the polymer matrix. Ultraviolet-Visible (UV-Visible) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric (TGA) analysis, Point of Zero Charge, X-ray diffraction (XRD), and Scanning electron microscopy (SEM) analysis have been used to characterise the Fe3O4 Nanoparticles and beta-CDHs@Fe3O4 nanocomposite. The synthesised beta-CDHs@Fe3O4 nanocomposite has been utilised for the adsorption of methylene blue (MB) dye from aqueous solutions. The maximum percentage removal of MB dye at optimum pH 7 and was found to be 98.51%. The adsorption capacity (q(e)) of beta-CDHs@Fe3O4 nanocomposite has been found to be 268.09 mg/g at optimum dosages 1.2 g/L, pH 7, temperature 25 degrees C, concentration 100 mg/L and an agitation speed of 200 rpm. Adsorption data have been fitted with three isotherm models namely Langmuir, Freundlich, and Temkin, and it was found to be the best fit with the Langmuir isotherm model. Kinetic studies like the pseudo-first order, pseudo-second order, and intra-particle diffusion model were also performed to study the adsorption mechanism. Further, thermodynamic studies demonstrate that the reaction was exothermic and spontaneous. Photocatalytic degradation of MB dye under visible light has also been studied, and 79.01% degradation of the dye was observed. Also, desorption of the nanocomposite was performed, and it was found to be reusable up to 5 times with 90% dye-desorption in the fifth cycle.