title: Synthesis and application of a quaternary phosphonium polymer coagulant to avoid N-nitrosamine formation.
abstract: Quaternary ammonium cationic polymers, such as poly(diallyldimethylammonium chloride) (polyDADMAC) are widely used for coagulating and removing negatively charged particles and dissolved organic matter (DOM) from drinking water. Their use, however, has been linked to the formation of carcinogenic N-nitrosamines as byproducts during chloramine-based drinking water disinfection. In this study, a novel quaternary phosphonium cationic polymer, poly(diallyldiethylphosphonium chloride) (polyDADEPC), was synthesized such that the quaternary nitrogen atom of polyDADMAC was substituted with a phosphorus atom. Formation potential tests revealed that even under strong nitrosation conditions, polyDADEPC and related lower-order P-based compounds formed oxygenated and not nitrosated products. Bench-scale jar tests using three different source waters further demonstrated that polyDADEPC achieved coagulation performance comparable to commercial polyDADMACs for particle and DOM removals within the typical dose range used for drinking water treatment. This work highlights the potential use of a phosphonium coagulant polymer, polyDADEPC, as a viable alternative to polyDADMAC to avoid nitrosated byproduct formation during chloramination.
authors.affiliation: Department of Civil and Environmental Engineering, Stanford University , 473 Via Ortega, Stanford, California 94305, United States.
authors.forename: Teng
authors.initials: T
authors.lastname: Zeng
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Pignatello
authors.forename: Russell Jingxian
authors.initials: RJ
authors.lastname: Li
authors.forename: William A
authors.initials: WA
authors.lastname: Mitch
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry; D064751:Ammonium Compounds / Q000737:chemistry; D002700:Chloramines / Q000032:analysis; D004203:Disinfection; D005427:Flocculation; D009602:Nitrosamines / Q000032:analysis*; D015538:Nitrosation; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry
chemical_list: D000498:Allyl Compounds; D064751:Ammonium Compounds; D002700:Chloramines; D009602:Nitrosamines; D009943:Organophosphorus Compounds; D011108:Polymers; D000644:Quaternary Ammonium Compounds; C508190:diallyldimethylammonium chloride; C030816:chloramine