title: Tertiary amines enhance reactions of organic contaminants with aqueous chlorine.
abstract: Through various anthropogenic inputs, tertiary amines can readily contaminate wastewater and drinking water sources and can form chlorammonium species (R(3)N(+)-Cl) during aqueous chlorine disinfection. This study investigated the less understood concept that these chlorammonium species can potentially enhance organic contaminant loss and increase disinfection byproduct formation to a greater extent than aqueous chlorine. Tertiary amines' effectiveness was highly dependent on amine structure as trimethylamine (TMA) and 4-morpholineethanesulfonic acid (MES) enhanced organic contaminant loss, while others (nitrilotriacetic acid (NTA) and creatinine (CRE)) were ineffective. MES addition up to 25 μM led to increased organic contaminant chlorination by up to three orders of magnitude while observing pseudo-first order kinetic behavior and a linear amine dose response. TMA addition up to 0.5 μM accelerated organic contaminant chlorination by almost two orders of magnitude, but occasionally deviated from pseudo-first order kinetics with incomplete organic contaminant degradation and a non-linear amine dose response - a result linked to TMA's rapid auto-decomposition over time. Byproduct formation was identical with and without amine addition, and thus the chlorination mechanisms are likely similar to aqueous chlorine. Results from this study improve the mechanistic understanding behind tertiary amine-enhanced chlorination.
authors.affiliation: School of Civil and Environmental Engineering, Georgia Institute of Technology, 200 Bobby Dodd Way, Atlanta, GA 30332, USA.
authors.forename: Amisha D
authors.initials: AD
authors.lastname: Shah
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Kim
authors.forename: Ching-Hua
authors.initials: CH
authors.lastname: Huang
mesh_terms: D000588:Amines / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D024841:Fluoroquinolones / Q000737:chemistry; D007700:Kinetics; D008744:Methylamines / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D020156:Salicylic Acid / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry; D014295:Trimethoprim / Q000737:chemistry; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000588:Amines; D024841:Fluoroquinolones; D008744:Methylamines; D009930:Organic Chemicals; D013451:Sulfonic Acids; D014874:Water Pollutants, Chemical; D014867:Water; D002713:Chlorine; D014295:Trimethoprim; C023336:trimethylamine; D020156:Salicylic Acid; C012976:flumequine