Removal of reactive dyes from wastewater by acrylate polymer beads bearing amino groups: isotherm and kinetic studies

The aim of this study was to prepare a novel resin for the removal of reactive dyes from aqueous media. To prepare the resin, poly(2-hydroxyethyl methacrylate/ethylene glycol dimethacrylate) beads were grafted with poly(glycidyl methacrylate) by surface-initiated atom transfer radical polymerisation. Epoxy groups of the grafted polymer were modified with tris(2-aminoethyl)amine ligand. The modified resin was characterised by swelling studies, FT-IR and SEM. Three different reactive dyes were selected (CI Reactive Brown 10, CI Reactive Red 120 and CI Reactive Green 5) and used in the removal studies. The effects of pH, temperature, ionic strength and initial dye concentration on the adsorption capacity of the resin were investigated. The adsorption capacity of the resin for Reactive Brown 10, Reactive Red 120 and Reactive Green 5 was 0.029 +/- 0.010, 0.032 +/- 0.0019 and 0.042 +/- 0.0013mmol/g resin (34.1 +/- 1.2, 47.6 +/- 2.3 and 69.3 +/- 1.7mg/g resin) respectively. The equilibrium adsorption data were analysed by Langmuir, DubininRadushkevich, Freundlich and Temkin isotherm models. A good fit was found between the Langmuir isotherm and data for the three dyes on resin. The adsorption kinetic data were modelled using pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic equations. It was found that the pseudo-second-order equation could describe the adsorption kinetics. The results indicated that the modified resin is an attractive alternative for removing reactive dyes from wastewater.