Photoreduction of hexavalent chromium induced by ferric-malate complexes

Key words: 
• Cr (Ⅵ) /
• Fe (Ⅲ) /
• malate /
• complexes /
• photoreduction

Abstract: The photochemical reduction of Cr(Ⅵ) in aqueous solutions containing Fe (Ⅲ)-malate complexes was preliminarily investigated, and the effects of different factors such as lights source, the initial pH, the initial concentrations of Fe (Ⅲ), malate and Cr(Ⅵ) were discussed in detail. The results indicate that hexavalent chromium can be efficiently photoreduced by Fe(Ⅲ)-malate complexes. The optimum pH for photoreduction of Cr(Ⅵ) is 3. The photoreduction efficiency of Cr(Ⅵ) can be enhanced by increasing the initial concentrations of Fe (Ⅲ) or malate. The initial rate of photoreduction increases with the concentration of each component. The concentration of Fe(Ⅲ) is the ratecontrolling factor. Fe(Ⅱ) generated by the photolysis of Fe (Ⅲ)-malate complexes is the main reductant.