**21. Conclusions**

The presence of biodegradable complexing agents of a new generation that is IDS and MGDA affects the sorption process of Cu(II), Zn(II), Cd(II) and Pb(II) ions on Dowex M4195 and Diphonix Resin®. The effectiveness of sorption depends on the type of complexes and their stability that facilitates their decomposition in the resin phase. The batch equilibrium was relatively fast and reached equilibrium after about 10-20 min of the contact. The experimental data have been analyzed using the Langmuir and Freundlich models. The sorption of studied metal ions in the presence of IDS and MGDA Dowex M 4195 and Diphonix Resin® followed the pseudo second order kinetics. As follows from the experiment pH does not have a significant effect on the sorption of Cu(II), Zn(II), Cd(II) and Pb(II) ions in the presence of IDS and MGDA on the chelating ion exchanger under consideration. The affinity of the above analyzed heavy metal complexes with IDS and MGDA Dowex M 4195 and Diphonix Resin® were found to be as follows: Pb(II) > Cd(II) > Cu(II) > Zn(II) for IDS and MGDA. The studied complexing agents can be proposed as alternative chelating agents to EDTA or NTA for the removal of heavy metal ions from waters and wastewaters.
