Sorption of Cd(II), Pb(II), Cu(II), and Zn(II) Complexes with Nitrilotris(Methylenephosphonic) Acid on Polystyrene Anion Exchangers

Abstract

The performance of the polystyrene anion exchangers Lewatit MonoPlus M 500, Lewatit MonoPlus M 600, Lewatit MonoPlus MP 500, Lewatit MonoPlus MP 64, and Lewatit MP 62 as well as Amberlyst A 21 was investigated for their further application in purification of wastewaters containing nitrilotris(methylenephosphonic acid) (NTMP) and heavy metal ions. The comparison involved evaluation of the sorption/desorption behavior of NTMP complexes of Cd(II), Pb(II), Cu(II), and Zn(II) on the resins with different basicity of functional groups. The batch method, in which a fixed amount of anion exchanger was contacted with the sample solution for increasing periods of time and the amount of metal ion remaining in the solution measured as a function of the elapsed time, was used to obtain information on the kinetics of species formed in the presence of added complexing agent. The effects of pH, metal(II) ion and ligand concentration, and their molar ratio on the sorption as well as type of functional groups of the anion ...