title: A comparative study of the effects of ozonation and TiO2-catalyzed ozonation on the selected chlorine disinfection by-product precursor content and structure.
abstract: This study compares the effects of ozonation (0.4-3.0 mg O(3)/mg DOC) and TiO(2)-catalyzed ozonation - TiO(2)-O(3) (0.4-3.0 mgO(3)/mg DOC; 1.0 mgTiO(2)/L) at pH 6 on the content and structure of natural organic matter (NOM) and trihalometane (THM) and haloacetonitrile (HAN) precursors in groundwater. The investigated groundwater from Northern Serbia is rich in NOM (9.85 mg/L DOC) which is mostly of hydrophobic character (65% fulvic acid and 14% humic acid fraction). It was found that the TiO(2)-catalyzed process, by favoring the radical mechanism of NOM oxidation, resulted in a more effective reduction in the content of total NOM (up to 18% DOC) compared to ozonation alone (up to 6% DOC). The use of TiO(2) also resulted in an improvement of ozonation in terms of THM precursor content removal (up to 80%). On the other hand, the application of both oxidation treatments resulted in an increase in the HANFP compared to the raw water. NOM oxidation during ozonation and TiO(2)-O(3) caused changes in their structure in the direction of an increased proportion of the hydrophilic fraction (up to 70%), which has the most reactive THM and HAN precursors, as well as the fraction with the highest content of their brominated species.
authors.affiliation: University of Novi Sad, Faculty of Sciences, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia. jelena.molnar@dh.uns.ac.rs
authors.forename: Jelena J
authors.initials: JJ
authors.lastname: Molnar
authors.forename: Jasmina R
authors.initials: JR
authors.lastname: Agbaba
authors.forename: Božo D
authors.initials: BD
authors.lastname: Dalmacija
authors.forename: Mile T
authors.initials: MT
authors.lastname: Klašnja
authors.forename: Milena B
authors.initials: MB
authors.lastname: Dalmacija
authors.forename: Marijana M
authors.initials: MM
authors.lastname: Kragulj
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D002384:Catalysis; D002713:Chlorine; D004203:Disinfection / Q000379:methods*; D060587:Groundwater / Q000032:analysis* / Q000737:chemistry; D006812:Humic Substances; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry; D055771:Serbia; D014025:Titanium; D022882:Trihalomethanes / Q000032:analysis / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D000097:Acetonitriles; D006812:Humic Substances; D022882:Trihalomethanes; C009495:titanium dioxide; D002713:Chlorine; D010126:Ozone; D014025:Titanium; C032159:acetonitrile