Cadmium removal performances of different dye ligands attached cryogel disks

Abstract

Poly(HEMA) cryogel disks were synthesized by free radical polymerization of 2-hydroxy-ethylmethacrylate (HEMA), and then Cibacron Blue F3GA (CB), Reactive Green 19 (RG) and Congo Red (CR) were immobilized as dye ligands. Disks were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and swelling degree, porosity calculations. Cd 2+ adsorption experiments were performed for 60 min. Maximum adsorption capacities were determined as 25.5 mg/g; 48.0 mg/g and 28.5 mg/g at pH = 7.0 for poly(HEMA)-CB; poly(HEMA)-RG and poly-(HEMA)-CR, respectively. Langmuir isotherm fitted best with the adsorption data and adsorption thermodynamics showed that Cd 2+ adsorption is thermodynamically favorable and a physisorption process. A great majority of adsorbed Cd 2+ desorbed with 1 M NaCl and cryogel disks can be re-used in adsorption experiments. Cd 2+ removal efficiencies of disks from human plasma are approximately 45%. Dye-attached cryogel disks synthesized in this study have potential in use for environmental and therapeutic applications.