Study on methyl orange adsorption capacity in water-based solutions using nano ZnO/chitosan composite

Nowadays, organic dyes are widely used in numerous industrial fields such as textile dyeing, cosmetics, paper, rubber, etc. However, the rapid development of these industries has significantly increased the amount of waste containing organic dyes released into the environment, thus, they need to be effectively treated. In this article, ZnO/chitosan nanocomposites (ZnO/CS) were synthesised by the co-precipitation method. After being successfully synthesised, ZnO/CS nanocomposite materials were characterised by X-ray diffraction spectroscopy, scanning electron microscopy and transmission electron microscopy. The results indicate that the average size of ZnO nanocrystals is about 29.6 nm. ZnO/CS nanocomposite materials have spherical and hexagonal particles ranging in size from 20 to 40 nm. The synthesised material was used to remove methyl orange from water-based solutions. The results demonstrate that the equilibrium adsorption time is reached after about 20-30 minutes, the adsorption results are more appropriately described by the Freundlich isotherm model, proving that the adsorption process is multilayer. The material is proven to have a good adsorption capacity of methyl orange with a maximum adsorption capacity of 33.90 mg/g, showing that the material is fully capable of further development to be applied as an adsorbent for organic dyes.