Modelling of basic blue-9 dye sorption onto hydrolyzed polyacrylonitrile grafted starch composite

Abstract

This study reports the synthesis of a superabsorbent hydrogel (HS) through the polyacrylonitrile (PAN) graft copolymerization and subsequent hydrolysis of corn starch. The surface morphology and chemistry, as well as the physicochemical characteristics of the hydrogel, were elucidated. The effectiveness of the synthesized hydrogel sorbent for remediating a basic blue-9 dye contaminated stream was subsequently investigated. Also, the relationship between the different process variables and the hydrogels’ remediation (sorption) capacity was studied, while the generated experimental kinetic and equilibrium data were effectively modelled using relevant isotherm and kinetic models. The Langmuir isotherm and pseudo-first-order kinetic models fitted best to the equilibrium and kinetic data, respectively. By applying specified mechanistic models, the intraparticle diffusion mechanism was identified as the sole rate-limiting step of the sorption process. The hydrogel showed excellent water absorption and monolayer sorption capacities of 710 ±1.6 g water/g and 343.27 ±1.3 mg/g, respectively. Thus, the hydrogel shows potential for the decontamination of dyestuff polluted streams.

Keywords

• Basic blue 9 dye
• Adsorption
• Hydrogel
• Corn starch
• Modelling