TiO2 Photocatalytic Removal of Hexavalent Chromium and Arsenic

M. I. LITTER

Congreso; VI CIPOA; 2025

This presentation is an overview of the work performed in our laboratories on the use of heterogeneous photocatalysis with TiO2 for the treatment of hexavalent chromium and arsenic in water. In the case of hexavalent chromium, direct reductive photocatalysis and indirect reduction by intermediates coming from ethylenediaminetetraacetic acid (EDTA) or citric acid added as electron donors are the main processes governing the removal of Cr(VI) by TiO2 photocatalysis. In the case of arsenic, removal can proceed by oxidation of As(III) to As(V), a very much studied process. However, reductive photocatalysis has been less studied and can take place under specific conditions, leading to the removal of As species by the formation of As(0) on the surface of the photocatalyst. While for As(III) direct reduction by photogenerated electrons is possible, As(V) reduction only proceeds in the presence of an electron donor such as methanol.