Photochemical oxidation of As (III) using hydrogen peroxide and UVC radiation

LESCANO, M.; ZALAZAR, C. S.; CASSANO, A. E.; BRANDI, R. J.

Paris

Congreso; IOA-IUVA World Congress & Exhibition 2011: Ozone and UV: Leading-edge Science and Technologies; 2011

Arsenic is an element widely distributed in nature. Its presence in water is due to natural occurrence or to anthropogenic activities. In groundwater, inorganic arsenic forms such as arsenate (V) and arsenite (III) are the most abundant abundant species. The arsenite form has more mobility, so it is more difficult to remove using traditional physical and chemical processes. The main objective of this research is to apply an Advanced Oxidation Process which combines ultraviolet radiation and hydrogen peroxide (UVC/H2O2) for the oxidation of aqueous solutions of As(III) and develop a plausible reaction mechanism useful to perform a subsequent kinetic study. For that purpose we built a discontinuous photochemical reactor (laboratory scale) with two 40W tubular germicidal lamps. In each run we followed the concentration of As (III), H2O2 and pH. The study was made beginning with a concentration of 200 ìg/L of As (III), changing the H2O2 concentration and the incident radiation on the reactor windows. Furthermore, we made actinometrical measures in order to obtain the value of the incident radiation, which is the boundary condition to solve the radiative transfer equation in the reactor. Thus, with all this information we should be able to develop, in the next work, a mathematical model of the reaction kinetics. The UV/H2O2 process results effective to oxidize arsenic (III) in water.