A study of Adsorption of Azure B and C from Aqueous Solutions on Poly (Acrylamide-co-Crotonic acid) Hydrogels Surface

Abstract

This study is concerned with the adsorption of azure B and C from solution on the surface of poly(AAm-co-CA) . The hydrogels have the ability to remove these dyes from aqueous solution, though not very efficient. UV-Visible-spectrophotometric technique has been used to produce quantitative adsorption data at different conditions of ionic strength and temperature. The adsorption isotherms are of S-curve type according to Giles classification and the experimental data were best fitted to Langmuir and Freundlich isotherm models. The results obtained show greater adsorption uptake of dyes on hydrogels. The adsorption phenomenon was examined as a function of temperature (15, 20, 25, 30 ^oC). The extent of adsorption of azure B and C on poly(AAm-co-CA) was found to decrease with increasing temperature (exothermic process). The basic thermodynamic functions have also been calculated. The adsorption of all adsorbates on this surface has increased with the increase of the ionic strength of solution.

Keywords: Adsorption, Azure B, Azure C, Hydrogels