Chitosan impregnated with magnetite as a versatile photocatalytic nanocomposite for Synozol Red KHL dye elimination from aqueous effluent

The combination of marine polysaccharides, chitosan (CS), that is signified as bio-polymeric substance with environmentally benign magnetite (Fe3O4) has led to an ever expanding of its applications. Such modification tends CS to be superparamagnetic photocatalyst and could be recoverable, recyclable and a sustainable material. Herein, Fe3O4 reinforced CS that is so-called Fe3O4@CS nanocomposite was fabricated in different proportions (Fe3O4@CS (2:1), (1:2) and (1:3) using simple co-precipitation route. The characteristics of the prepared samples were investigated to explore their structure and morphology using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometer. Thereafter, the polymer-based photocatalyst was used as a Fenton's reaction for oxidation of Synozol Red KHL dye in aqueous media. The effects of several operational parameters on the photocatalytic performance are also described. In addition, the catalyst recyclability is achieved to attain its activity after 6th cycles with high removal efficiency. The process optimisation using response surface methodology is conducted and the optimal operational conditions recorded are 465 and 2 mg/L for H2O2 and Fe3O4@CS nanocomposite, respectively at pH 2.0. The dye removal reached to a complete mineralisation (100%) within 30 min of irradiance time. Kinetic data revealed the oxidation system follows the first-order reaction kinetic and the thermodynamic parameters confirmed the reaction is endothermic and non-spontaneous in nature. The reaction confirmed its sustainability since it is applied using solar energy as an economic source with 100% removal within 30 min in the solar reactor.

Automated summary

In this study, a nanocomposite called Fe3O4@CS was fabricated by combining marine polysaccharides chitosan (CS) with environmentally friendly magnetite (Fe3O4). The Fe3O4@CS nanocomposite exhibited superparamagnetic photocatalytic properties, making it a sustainable material with the ability to be recovered and recycled.