Photocatalysis with easily recoverable linear engineered TiO2 nanomaterials to prevent the formation of disinfection byproducts in drinking water

Two photocatalytic linear engineered TiO2 nanomaterials (LENs) were synthesized and evaluated against commercial standard P25 TiO2 nanoparticles in terms of their effects on common parameters used to measure and characterize natural organic matter (NOM) and disinfection byproduct (DBP) precursors in drinking water. DBPs, some of which have been linked to cancer and other negative human health outcomes, are regulated in most jurisdictions in North America and Europe as well as parts of Asia, Africa, and South America, and the removal of DBP precursors is a central goal of conventional drinking water treatment plants. All three of the nanomaterials evaluated in this study were capable of degrading NOM, including DBP precursors, when irradiated with UVA LED light. The materials differed in terms of crystal phase, surface morphology, and available surface area. These differences impacted the predominant NOM removal processes occurring in each case and consequently the overall treatment efficacy of the two materials in two different water sources. One of the LENs evaluated in this study, designated NB 700, reduced the DBP formation potential of one of the water sources by 90% and was readily removed from the water via filtration. Irrespective of the nanomaterial employed, DBP precursor degradation was faster in the water source with higher NOM and lower alkalinity and hardness. The electrical energy per order (EEO) required to degrade DOC and THM precursors in one of the water sources was comparable to reported values for the degradation of these compounds with UV/H2O2, another advanced oxidation process.