Synthesis of nano-sized chitosan blended polyvinyl alcohol for the removal of Eosin Yellow dye from aqueous solution

The current investigation aimed at synthesizing the nano-sized chitosan particles and blending it with the polyvinyl alcohol (PVA). This composite proved to be a good adsorbent for the removal of Eosin Yellow (EY) dye from the aqueous solution. The characterisation studies like TEM, SEM, XRD and FT-IR were carried out for the chitosan/PVA blend. The removal of EY dye by the chitosan/PVA composite was optimized by varying the certain operating parameters such as initial dye concentration, adsorbent dose, solution pH, contact time and temperature. The adsorption isotherms for the adopted system were studied in association with Langmuir, Freundlich and Temkin adsorption models. The adsorption isotherm data was best adopted with the Langmuir model. The Langmuir monolayer adsorption capacity of the chitosan/PVA blend for EY dye molecules was calculated as 52.91 mg/g. Adsorption kinetic data were applied to the pseudo-first order, pseudo-second order, Weber and Morris intraparticle diffusion and Boyd kinetic models. The adsorption kinetic was best obeyed with the pseudo-second order kinetics. The thermodynamic parameters were evaluated for the present system and it was found that the present system was spontaneous and exothermic in nature. The adsorbed EY dye molecules were desorbed from the spent chitosan/PVA using HCl solution. The desorption results indicates that the recovered adsorbent can be effectively reused for further adsorption cycles. The prepared material possesses excellent adsorption potential to treat the industrial dye wastewater.