Degradation of disinfection byproducts by carbonate green rust.
Disinfection byproducts (DBPs) in drinking water flowing through corroded iron or steel pipes may encounter carbonate green rust (GR(CO32-)), a mixed Fe(II)/Fe(lll) hydroxide mineral and potent reductant. This research was performed to investigate the kinetics and pathways of the degradation of selected halogenated DBPs in the presence of GR(C032-). Trichloronitromethane was rapidly degraded to methylamine via sequential hydrogenolysis followed by nitro-reduction. Haloacetic acids reacted solely via sequential hydrogenolysis. Trichloroacetonitrile, 1,1,1-trichloropropanone, and trichloroacetaldehyde hydrate were transformed via hydrolysis and hydrogenolysis. Chloroform was unreactive over 300 h. The buffer identity affected reductive dehalogenation rates of DBPs, with faster rates in MOPS buffer than in carbonate buffer, the latter being representative of the buffer in drinking water systems. GR(CO32-) was unstable in both buffers and transformed to magnetite within 48 h. Thus, slower reacting compounds (half life >3 hours) were transformed by a combination of minerals. Reductive dehalogenation kinetics were influenced by DBP chemical structure and correlated with one-electron reduction potential.
Chun
Chan Lan
CL
Department of Civil Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, USA.
Hozalski
Raymond M
RM
Arnold
William A
WA
D004202:Disinfectants / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis
D004202:Disinfectants; D005290:Ferric Compounds; D005296:Ferrous Compounds; D014874:Water Pollutants, Chemical