Photocatalyzed degradation of metal-EDTA complexes in TiO₂ aqueous suspensions and simultaneous metal removal

Cu(II)-, Fe(III)-, and Zn(II)-EDTA complexes are degraded rapidly in aerated aqueous suspensions of TiO₂ with a high-pressure mercury lamp (irradiation wavelength > ca.290 nm), accompanying a full removal of the metals. Total organic carbons (TOCs) in their solutions decrease with the irradiation time, however. TOCs remained after 5 h irradiation. Although Co(II)-and Ni(II)-EDTA complexes are degraded, the removal of their metals is slow. Mn(II)-EDTA complex is degraded incompletely even after 5h irradiation.