Modification of Karaya gum by graft copolymerization for effective removal of anionic dyes

ABSTRACT

A graft copolymer gel based on the ‘Karaya gum’ has been made by grafting Karaya gum (KG) with 2-(methacryloyloxyethyl)trimethylammonium chloride (METAC) via microwave irradiation technique. The swelling of the gel appeared to be a second-order kinetic process following Fickian diffusion. The material exhibited significant adsorption capacity for anionic dyes, namely, indigo carmine, methyl orange, Remazol brilliant blue R and Direct Black 38 from aqueous solution. The pseudo-first-order kinetic model and Freundlich isotherm models provided good correlation with the dye adsorption data on KG-g-PMETAC. Thermodynamic studies revealed the adsorption process to be endothermic in all cases.

KEYWORDS:

• Karaya gum
• anionic dyes
• adsorption
• dye removal