Formation of brominated products in irradiated titanium dioxide suspensions containing bromide and dissolved organic carbon

We report the irradiation of TiO2 suspensions containing Br-Br- and dissolved organic carbon (DOC). In the absence of DOC, we found no evidence for the formation of BrO3- upon irradiation of 1gL-1 P25 suspensions with UV light for initial Br-Br- concentrations up to 10mgL-1. In the presence of DOC (Lake Hohloh, Germany and salicylic acid), we found no evidence for the formation of either BrO3- or trihalomethanes (THMs). However, small amounts of adsorbable organic halogen (AOX) were formed at high bromide concentrations (3mgL-1). When irradiating P25 suspensions containing bromide and 2,4-dihydroxybenzoic acid (DHBA, high bromoform formation potential), we observed the formation of significant amounts of bromoform (up to 10μgL-1). Bromoform appeared only after the DHBA had been degraded.