Recycling of photocatalysis-reduced Cr(VI) in metal surface passivation protection

The hexavalent chromium waste solution after photocatalysis treatment was reused for surface passivation of low carbon steel (sample p-HCC), to improve its corrosion resistance. The structure and the anticorrosion properties of p-HCC were confirmed by SEM, XPS, electrochemical impedance spectroscopy. Compared with passivation samples treated by pure Cr(III) solution (sample TCC), the polarization resistance of p-HCC film (2994 omega cm(2)) was larger than that of TCC (2043 omega cm(2)), which may be due to the higher Cr content in p-HCC film (p-HCC: 0.71 atom%, TCC: 0.13 atom%), which was caused by a better interaction between Fe ions and Cr-compound due to Cr(VI) residue and photocatalyst in the photocatalysis reduction for hexavalent chromium. [GRAPHICS]

Automated summary

In this study, the hexavalent chromium waste solution after photocatalysis treatment was used for surface passivation of low carbon steel to improve its corrosion resistance. The structure and anticorrosion properties of the passivated steel were analyzed, and it was found that the polarization resistance of the p-HCC film was larger compared to the film treated with pure Cr(III) solution, which may be attributed to the higher Cr content and better interaction between Fe ions and Cr-compound in the p-HCC film.