Bromide-assisted catalytic oxidation of lead(<scp>ii</scp>) solids by chlorine in drinking water distribution systems

Orta, John; Patton, Sharyle; Liu, Haizhou

doi:10.1039/c7cc02533e

Cited by 7 publications

(3 citation statements)

References 32 publications

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“…To start a 7-day oxidation experiment between a solid and oxidant, 20 g/L suspension of a pipe corrosion scale solid or 10 mg/L suspension of a reference solid was mixed with 200 mg Cl 2 /L (equivalent of 2.8 mM) of HOCl or HOBr in a 250 mL glass vessel in darkness. The choice of an oxidant concentration higher than 2 mg Cl 2 /L in these experiments did not change the redox ladder compared to that in drinking water conditions and provides valuable insight into the oxidation kinetics, a technique used in prior studies. ,,, Because bromide reacts instantaneously with HOCl to form HOBr, HOBr was directly used to understand the bromide effect on the oxidation of iron corrosion scales by chlorine, a technique also used in prior studies . The pH of the suspension was maintained at 7 ± 0.1 throughout the reaction with a Eutech Instrument Alpha pH200 controller.…”

Section: Methodsmentioning

confidence: 99%

“…12,13,25,26 Because bromide reacts instantaneously with HOCl to form HOBr, 27 HOBr was directly used to understand the bromide effect on the oxidation of iron corrosion scales by chlorine, a technique also used in prior studies. 26 The pH of the suspension was maintained at 7 ± 0.1 throughout the reaction with a Eutech Instrument Alpha pH200 controller. At each time point, 0.2 mL of suspension was collected, filtered through 0.22 μm filters, and diluted by 100 times to measure the HOCl or HOBr concentration, and additional HOCl or HOBr was added into the reactor to adjust its concentration back to 200 mg Cl 2 /L.…”

Section: Preparation Of Iron Corrosion Scales and Crmentioning

confidence: 99%

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Hexavalent Chromium Release in Drinking Water Distribution Systems: New Insights into Zerovalent Chromium in Iron Corrosion Scales

Tan

Avasarala

Liu

2020

Environ. Sci. Technol.

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Upon cast iron corrosion in contact with residual disinfectants, drinking water distribution systems have become potential geogenic sources for hexavalent chromium Cr(VI) release. This study investigated mechanisms of Cr(VI) release from cast iron corrosion scales. The oxidation of the corrosion scales by residual disinfectant chlorine released Cr(VI) and exhibited a three-phase kinetics behavior: an initial 2 h fast reaction phase, a subsequent 2-to-12 h transitional phase, and a final 7-day slow reaction phase approximately 2 orders of magnitude slower than the initial phase. X-ray absorption spectroscopy analysis discovered that zerovalent Cr(0) coexisted with trivalent Cr(III) solids in the corrosion scales. Electrochemical corrosion analyses strongly suggested that Cr(0) in the corrosion scales originated from Cr(0) in the cast iron alloy. Cr(0) exhibited a much higher reactivity than Cr(III) in the formation of Cr(VI) by chlorine. The presence of bromide in drinking water significantly accelerated Cr(VI) release because of its catalytic effect. Meanwhile, chlorine consumption was mainly attributed to the oxidation of organic matter and ferrous iron. Findings from this study point to a previously unknown but important pathway of Cr(VI) formation in drinking water, that is, direct oxidation of Cr(0) by chlorine, and suggest new strategies to control Cr(VI) in drinking water by inhibiting Cr(0) reactivity.

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Section: Methodsmentioning

confidence: 99%

Section: Preparation Of Iron Corrosion Scales and Crmentioning

confidence: 99%

Hexavalent Chromium Release in Drinking Water Distribution Systems: New Insights into Zerovalent Chromium in Iron Corrosion Scales

Tan

Avasarala

Liu

2020

Environ. Sci. Technol.

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“…In recent surveys by American Water Works Association, approximately 30% of community water systems reported service lines containing lead, and the total number of lead service lines in the United States was estimated to be 6.1 million . Besides lead pipes, lead-containing brass and lead–tin solder are still widely present in many premise plumbing systems and essentially exist as nonpoint sources of lead. , When exposed to residual chlorine disinfectant in drinking water, lead plumbing materials are oxidized to solid lead dioxide (PbO 2 ). − The PbO 2 (s) can react with reducing components in water to generate soluble Pb(II). − Per the Lead and Copper Rule by the U.S. EPA, the concentration of dissolved lead should not exceed an action level of 15 μg/L. The guideline value for lead in drinking water set by World Health Organization is 10 μg/L…”

Section: Introductionmentioning

confidence: 99%

Differential Cytotoxicity of Haloaromatic Disinfection Byproducts and Lead Co-exposures against Human Intestinal and Neuronal Cells

Liu

Olson

Qiu

et al. 2020

Chem. Res. Toxicol.

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Disinfecting drinking water with chlorine inadvertently generates disinfection byproducts (DBPs) which can cause potential adverse health effects to humans. Haloaromatic DBPs are a group of emerging DBPs recently identified, suspected to be substantially more toxic than haloaliphatic DBPs but have not been extensively studied. Simultaneously, service pipelines made of lead materials are widely used in water distribution systems and become a source of dissolved lead (Pb) in tap water. In this study, we investigated the cytotoxicity of nine haloaromatic DBPs and lead ion (Pb 2+ ), both separately as well as in combination, to human epithelial colorectal adenocarcinoma (Caco-2) and neuroblastoma (SH-SY5Y) cells. Results show that the cytotoxicity of the DBPs against Caco-2 cells followed the descending rank order of 2,4,6-triiodophenol ≅ 2,5-dibromohydroquinone > 2,4,6-tribromophenol > 3,5-dibromo-4-hydroxybenzaldehyde ≅ 2,4,6-trichlorophenol > 4-chlorophenol ≅ 3,5-dibromo-4-hydroxybenzoic acid > 2,6-dichlorophenol >5-chlorosalicylic acid, and the cytotoxicity of the DBPs against SH-SY5Y cells followed a similar rank order, 2,4,6-triiodophenol ≅ 2,5-dibromohydroquinone > 2,4,6-tribromophenol > 3,5-dibromo-4hydroxybenzaldehyde ≅ 2,4,6-trichlorophenol > 4-chlorophenol > 3,5-dibromo-4-hydroxybenzoic acid > 2,6-dichlorophenol ≅ 5chlorosalicylic acid. Lead in water did not change the toxicity of 3,5-dibromo-4-hydroxybenzoic acid (to either cell-type) or the toxicity of 4-chlorophenol (to the neuronal cell-type); but Pb 2+ exhibited different degrees of synergistic effects with other tested DBPs. The synergism resulted in different rank orders of cytotoxicity against both intestinal and neuronal cells. These data indicate that future prioritization and regulation of emerging haloaromatic DBPs in drinking water should be considered in terms of their own toxicity and combinatorial effects with lead in water.

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Techniques for Assessing Metal Mobility in the Environment: A Geochemical Perspective

Avasarala

2021

Practical Applications of Medical Geology

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Bromide-assisted catalytic oxidation of lead(ii) solids by chlorine in drinking water distribution systems

Cited by 7 publications

References 32 publications

Hexavalent Chromium Release in Drinking Water Distribution Systems: New Insights into Zerovalent Chromium in Iron Corrosion Scales

Hexavalent Chromium Release in Drinking Water Distribution Systems: New Insights into Zerovalent Chromium in Iron Corrosion Scales

Differential Cytotoxicity of Haloaromatic Disinfection Byproducts and Lead Co-exposures against Human Intestinal and Neuronal Cells

Techniques for Assessing Metal Mobility in the Environment: A Geochemical Perspective

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