PRETREATMENT OF COMPLEXED METAL WASTEWATERS

This study investigates the applicability of hydroxide precipitation t o complexed metal wastewaters using inorganic cations that may functio n as ligand sharing agents. Within this context Ca2+, Fe2+, Fe3+, Mn2 and Mg2+ cations with the metals Cd and Cu and EDTA and NTA as ligand s are used to define the systems for which theoretical and experimenta l evaluations are made. Results indicate that calcium is the only cati on that effectively binds the ligands that makes it possible to apply the hydroxide precipitation. Fe2+ and Mn2+ are not effective due to th eir rapid oxidation. Mg2+ is found partly effective but, may not be ad equate for pretreatment purposes.