A Study on the Adsorption of Rare Earth Elememts by Raw and Crosslinked Chitosan

The adsorption characteristics of raw and crosslinked chitosan for rare earth elements (REEs) have been studied. The range of optimum pH for the maximum adsorption was observed: pH 4.5~5.5 for , on raw and crosslinked chitosan; pH 4.0~5.5 for and on crosslinked chitosan and pH 2.0 for those on raw chitosan. The adsorption rate of REE at pH 4.0 has been found in the order of > > > > > > > > > > > > in single metal system and that of > > > > > > > > > > in multi metal system. In the competitive adsorption of multi metal system, the amount of metal adsorption generally increased with increasing atomic number and with decreasing ionic radius. On the adsorption studies of metal ions on chitosan, the time of equilibrium adsorption which was reached at the maximum adsorption was about 5 hours. 83~95 % for ion and 90~106 % for ion, were recovered from the crosslinked chitosan.