Irradiation Studies of Nickel Ethylenediaminetetraacetic Acid Complexes in the Presence of Titanium Dioxide

Shafer, Jonathan, Cleo Vidican, Emily Rames, and Katherine Lanigan

Ethylenediaminetetraacetic acid (EDTA) is the most widely produced chelating ligand in the world, with uses in many types of industrial and consumer products, medical treatments, and metal waste remediation. EDTA is also a recalcitrant chemical and as a result can be found at potentially harmful concentrations in rivers and lakes. The potential problem with EDTA is its ability to mobilize metals from sediments and aquifers, alter speciation of metals, and influence metal bioavailability. The goal of this research is to identify the photo-degrative pathway of EDTA when complexed with nickel and adsorbed to titanium dioxide particles. It is proposed that the general mechanism of degradation is through photocatalytic oxidation (PCO). Ultraviolet/visible absorption spectroscopy is for identification of the nickel-EDTA complex and products of irradiation experiments. Experiments include pH dependence, substitution of titanium dioxide with a similar product called Adsorbsia , and use of the Nash reagent for identification of products of irradiation.