Prof. Katsoyiannis (Aristotle University of Thessaloniki) visits LTQE

© 2015 EPFL

© 2015 EPFL

Prof. Ioannis Katsoyiannis from the Department of Chemistry at Aristotle University of Thessaloniki, Greece, visits LTQE from July 1st to September 30th 2015.

Professor Katsoyiannis research team investigates major water quality issues and develops/optimizes advanced water treatment technologies for safe drinking water supply. In particular, the group focuses on groundwater treatment for removal of inorganic contaminants such as arsenic, chromium, uranium and antinony. New materials (such as adsorbents or novel coagulants) or hybrid treatment technologies (such pipe flocculation coupled with ultrafiltration) are investigated for efficient water treatment and applied in small pilot units in the lab or the field.

The present project will investigate the fate of Cr(III) during oxidative water treatment with ozone. This kinetic and mechanistic study is highly relevant because it has been decided to upgrade municipal wastewater treatment plants in Switzerland with an ozonation step for micropollutant removal. At the same time, Cr(III), the prevalent form of chromium in wastewater, might be oxidized to the significantly more toxic Cr(VI).

The core objectives of the project are as follows:

a) Identification of the stoichiometry of reaction between Cr(III) and ozone or hydroxylradicals
b) Determination of pH dependence of the second order rate constants for the reaction of ozone with Cr(III) in aqueous solutions in absence and presence of ligands
c) Kinetics of the oxidation of Cr(III)(OH)3(s) particles and formation of Cr(VI). Determination of surface controlled rate constants.
d) Study of Cr(III) oxidation in real municipal wastewater samples