Mechanism of sorption equilibrium in the recovery of zinc, calcium, and magnesium from waste water by the use of iminodiacetate resins

A study is made of the laws that govern the sorptive equilibrium of zinc, calcium, and magnesium in aqueous solutions on iminodiacetate commercial resin Lewatit TP 207. The relations that are obtained show that the cation sorption process is described by the Langmuir and Freundlich models. The selectivity series Zn2+ > Ca2+ > Mg2+ was established based on determination of the affinity constants in the corresponding equations. Thus, the resin can be used to remove zinc cations from waste water even when it contains high concentrations of hardness ions. © 2013 Springer Science+Business Media New York.