Investigation of disinfection by-product precursors removal by catalytic ozonation process

The use of iron coated pumice (ICP) for heterogeneous catalytic ozonation significantly enhanced the removal efficiency of natural organic matters (NOMs) that are known as the precursors of disinfection by products (DBPs), in aqueous solution compared with alone ozonation and adsorbtion because of the synergistic effect of hybrid process. The catalyst surface property is a key factor due to ozone utilization efficiency and the production of hydroxyl radical (OH•), so a systematic investigation of the catalytic reaction mechanism of ICP surface was realized using the reaction kinetics. The multiple characterization analysis (XRD, FT-IR, TEM, BET, DLS, and pHPZC) were employed to investigate the coating procedure efficiency on surface texture and physico-chemical properties of the catalyst surface. The contributions of direct/indirect ozonation and surface adsorption to NOM degradation by heteregenous catalytic ozonation were identified by the reaction kinetic analysis using the tert-Butyl alcohol (TBA) as a radical scavenger, confirming that surface ferrous iron loading promoted the role of the hydroxyl radical reaction. The phosphate was used as an inorganic probe and remarkably inhibited the removal efficiency of catalytic NOM ozonation due to quenching of OH• in solution, and not the interface reaction. ICP is an effective green catalyst for DOM degradation in aqueous solution.