Impact of NOM character on copper adsorption by trace ferric hydroxide from iron corrosion in water supply system
MetadataShow full item record
The fate of trace concentrations of cupric sulfate (<0.4 mg/L) dosed into chloraminated distribution systems to inhibit nitrification has been shown in this study to be controlled by at least two crucial factors: the character of natural organic matter (NOM) and iron hydroxide corrosion products present at low concentrations (<2 mg/L). This research quantified the removal of Cu(II) ions added into waters containing trace Fe(OH)3 flocs and the effect of NOM of different character on this removal. The dominant dissolved copper species in NOM-containing waters were found to be Cu(II)–NOM complexes. Both intramolecular chelation and intermolecular complexation can occur, with the latter occurring preferentially and resulting in the aggregation of smaller organic molecules to form larger molecules. The presence of ferric hydroxide flocs when Cu(II) ions were added into NOM-containing waters was shown to result in removal of Cu(II) ions, presumably as Cu(II)–NOM complexes. This removal was through adsorption processes obeying Freundlich isotherms, although the presence of larger NOM molecules and heterogeneous copper species (e.g. Cu(OH)2(s) and CuO(s)) appeared to shield smaller Cu(II)–NOM complexes from adsorption to some extent. For the strategy of inhibition of nitrification in distribution systems by the addition of Cu(II) ions, complexation of Cu(II) ions by NOM and adsorption of Cu(II)–NOM complexes by ferric hydroxide flocs released from pipe walls pose significant operational challenges to maintaining the concentration of Cu(II) ions through the distribution system.
NOTICE: this is the author’s version of a work that was accepted for publication in Chemical Engineering Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Chemical Engineering Journal, Vol.200-202, August, 2012. DOI:10.1016/j.cej.2012.06.018
Showing items related by title, author, creator and subject.
Effect of iron corrosion on the fate of dosed copper to inhibit nitrification in chloraminated water distribution systemZhan, Weixi (2011)Nitrification has been acknowledged as one of the major barriers towards efficient chloramination in water supply distribution systems. Many water utilities employing monochloramine as the final disinfectant have been ...
Effectiveness of Ferric Salts to Remove Low Levels of Dosed Copper from NOM-Containing Natural WaterZhan, Weixi; Sathasivan, Arumugam; Nolan, P.; Koska, L.; Heitz, Anna; Joll, Cynthia (2009)Water utilities dose copper in drinking water systems to inhibit/kill microorganisms including algae. Under conditions observed in the systems, the majority of dosed copper is reported to be in dissolved forms of Cu-NOM ...
Zhan, Weixi (2007)Chloramine as a secondary disinfectant has been widely used by many water utilities around the world especially in a distribution system requiring a longer retention time such as the 600km long Goldfield water distribution ...