Removal of aluminium by Alizarin Yellow-attached magnetic poly(2-hydroxyethyl methacrylate) beads

摘要

Since the discovery of the implication of aluminium in dialysis encephalopathy, much progress has been made in the preparation of dialysis water from which the metal is now virtually excluded. In this study, Alizarin Yellow-attached magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) beads were investigated as a specific adsorbent for aluminium removal from both drinking and dialysis water. Magnetic PHEMA beads in the size range of 80-120 μm were produced by a dispersion polymerization technique. Then Alizarin Yellow was covalently attached onto mPHEMA beads. Al(Ⅲ) adsorption from aqueous solutions was examined in a batch system. Alizarin Yellow-attached mPHEMA beads were characterized by scanning electron microscopy (SEM) and elemental analysis. The mPHEMA beads have a spherical shape and porous structure. Alizarin Yellow loading was found to be 208 μmol/g polymer. Non-specific Al(Ⅲ) adsorption was about 23 μmol/g polymer. Alizarin loading greatly improved the adsorption capacity (420 μmol/g polymer). The maximum Al(Ⅲ) adsorption was observed at pH 5.0. Adsorption capacity of the Alizarin Yellow-attached beads from drinking and dialysis water for Al(Ⅲ) ions was higher than that for other ions (i.e. Cu(Ⅱ), Fe(Ⅲ) and Zn(?)). More than 90% of the adsorbed Al(Ⅲ) ions were desorbed successfully using 2.0 M HNO_3 solution. It was possible to reuse these Alizarin Yellow-attached mPHEMA beads without significant losses in the Al(Ⅲ) adsorption capacities.