Preparation of magnetic dye affinity adsorbent and its use in the removal of aluminium ions

Aluminium has recently been considered as a causative agent in dialysis encephalopathy, osteodystrophy, and anemia occuring in hemodialysis patients. The aim of this study is to prepare magnetic poly(2-hydroyethylmethacrylate) (mPHEMA) adsorbent and to investigate it's useability for the removal of AI(III) ions from drinking and dialysis water. Magnetic PHEMA beads in a size range 80-120 μm were produced by a dispersion polymerization technique. Then Alizarin Red was covalenlty attached onto the mPHEMA beads. Al(III) adsorption from aqueous solutions was examined by batch system. mPHEMA beads were characterized by swelling tests, electron spin resonance (ESR), scanning electron microscopy (SEM), and elemental analysis. Important results obtained in this study are as follows: the swelling ratio of mPHEMA beads was 34%. The presence of magnetite in the polymeric structure was confirmed by ESR. The mPHEMA beads have a spherical shape and porous structure. Alizarin Red loading was 135.8 μmol g^-1 polymer. The maximum Al(III) adsorption was 722 μmol g^-1 polymer at pH 5.0. Non-specific Al(III) adsorption was about 23 μmol g^-1 polymer under the same conditions. High desorption ratios (98%) were achieved by using 0.1 M HNO₃. It was possible to reuse the beads without significant loss of Al(III) adsorption capacity.