Coupled selective adsorption and ozonation for non biodegradable COD removal

Abstract

This paper investigates a new water treatment process based on the combined use of the pollutant adsorption onto a mineral surface, and the ozonation of the adsorbed species. Dioxane has been chosen as a model compound as it is refractory towards ozone alone, and two adsorbents (a high silica zeolite FAU and a mesoporous material M) are tested. Three sets of experiments are shown: pollutant adsorption alone, pollutant ozonation alone and the coupled adsorption/ozonation process. The first results show that FAU is not a well suited adsorbent, as dioxane adsorption itself is weak and, moreover, the coupled process does not induce any benefit. On the other hand, mesoporous material M gives better results, since dioxane removal has been achieved up to 50%. The difference between the two materials is attributed to their catalytic effect: whereas FAU does not react with ozone, M probably decomposes the oxidant, generating free radical species and thus acting as an advanced oxidation process.