Effects of selected water chemistry variables on copper pitting propagation in potable water

Ha, Hung M.; Taxén, Claes; Williams, Keith A.; Scully, John R.

doi:10.1016/j.electacta.2011.04.008

Cited by 40 publications

(58 citation statements)

References 44 publications

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“…Therefore these corrosion products could precipitate. This analysis is consistent with the experimental observation and results from a finite element model 26,31 where malachite and brochantite were the main corrosion products outside pits (where the pH was near neutral) while cuprite and nantokite formed at the pit bottom (due to their solubility being so low and independent of pH) (Figures 6 to 9 and Table II). This analysis, even though simplified, gives better understanding about the role of HCO 3 − , SO 4 2− and Cl − on pit kinetics.…”

Section: Summary Of Chemical Analysis By Edx and Molecular Identitysupporting

confidence: 90%

“…31 Flush mounted copper wires were intentionally selected and corroded to produce pits with a constant cross-sectional area. Similar behavior was observed in hemispherical pits but these are complicated by changing pit areas.…”

Section: Methodsmentioning

confidence: 99%

“…Similarly, switching the bulk solution from HCO 3 − + SO 4 2− to HCO 3 − + Cl − increased the value of Q for nantokite from 0 in HCO 3 − + SO 4 2− solution to approximately 10 −4 M 2 assuming the concentrations of Cu(I) and Cl − at the pit bottom were 10 −3 and 10 −1 M as calculated by finite element modeling. 31 This value of Q was larger than the solubility product of nantokite (K sp = 1.86 × 10 −7 M 2 ) indicating the likely precipitation of this corrosion product compound. This is consistent with the experimental c It is recognized that the thermodynamically stable equilibrium corrosion products may not accurately represent all metastable states possible under transient conditions in a pit.…”

Section: Summary Of Chemical Analysis By Edx and Molecular Identitymentioning

confidence: 95%

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Artificial Pit Study on Effects of Bulk Solution Composition Changes on Copper Pitting Propagation in Synthetic Potable Waters

Scully

2012

J. Electrochem. Soc.

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The effects of step changes in the concentration of HCO 3 − , Cl − and SO 4 2− on copper pitting propagation in simulated potable waters were investigated. HCO 3 − and Cl − additions were found to stifle propagation of previously established pits. Raising the applied potential could restart pit growth temporarily. In contrast, SO 4 2− was able to reactivate stifled pits without a potential increase. Stifling of pit growth upon HCO 3 − and Cl − additions was attributed to the formation of highly resistive malachite and copper chloride layers. The detrimental effect of SO 4 2− was attributed to the chemical dissolution of the resistive copper chloride layer and the formation of a porous brochantite pit cap.

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Section: Summary Of Chemical Analysis By Edx and Molecular Identitysupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Summary Of Chemical Analysis By Edx and Molecular Identitymentioning

confidence: 95%

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Artificial Pit Study on Effects of Bulk Solution Composition Changes on Copper Pitting Propagation in Synthetic Potable Waters

Scully

2012

J. Electrochem. Soc.

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“…Atacamite is less soluble than cupric hydroxide or malachite, reported as the solid by-products that control copper solubility and dominate the speciation of Cu(II) between pH 5 and 9 [43] in new and aged pipe systems, respectively. Hence, free chlorine could be reduced to chloride and precipitated as nantokite, which is re-oxidized and covered by layers of malachite, cupric hydroxide, or other stable solid phases of Cu(II) that control the copper solubility and the release of copper into the water [44]. This is likely to occur in acidic microenvironments formed on the surface where the metallic copper oxidation takes place.…”

Section: Resultsmentioning

confidence: 99%

Chlorine Reduction Kinetics and its Mass Balance in Copper Premise Plumbing Systems During Corrosion Events

et al. 2019

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Hypochlorous acid has been reported as the main oxidant agent responsible for the corrosion of copper plumbing systems in chlorinated water supplies. However, there is little information about chlorine consumption kinetics in a combined system (i.e., with dissolved oxygen (DO) and free chlorine), as well as its complete mass balance within a copper pipe during stagnation. The results of our experiments using copper pipes filled with synthetic drinking water, with a moderate alkalinity (pH = 7.2; dissolved inorganic carbon = 80 mg as CaCO3 /L), and tested under chlorine concentrations from 0 to 8 mg/L, show that chlorine depletion is associated with pipe wall reactions (i.e., copper oxidation and scale formation processes). Free chlorine was depleted after 4 h of stagnation and its kinetic constant depend on the initial concentration, probably due to diffusion processes. Surface analysis including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and total reflection X-ray fluorescence (T-XRF) suggest chlorine precipitation, probably as CuCl. The obtained kinetics of chlorine and DO reduction would be critical for modeling and prediction of corrosion events of copper premise plumbing systems. In addition, our results indicate that the pipe’s surface reactions due to corrosion induces a loss of free chlorine in the bulk water, decreasing chlorine added for disinfection and the subsequent effect on water quality.

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“…They account for wide spread prod ucts of the cor ro sion of metal el ements made of cop per and its al loys (Dill, 2009;Šatoviae et al, 2010;Ha et al, 2011;Kierczak et al, 2012). Dis so lu tion and reac tions in volv ing SCM from both mine sites and wastes can liber ate cop per to un der ground and groundwaters, thus in flu encing the qual ity of drink ing wa ter.…”

Section: Introductionmentioning

confidence: 99%

Recently forming secondary copper minerals as indicators of geochemical conditions in an abandoned mine in Radzimowice (SW Poland)

Siuda

Kruszewski

2013

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1 In sti tute of Geo chem is try, Min er al ogy and Pe trol ogy, Uni ver sity of War saw, ¯wirki i Wigury 93, 02-089 Warszawa, Po land 2 In sti tute of Geo log i cal Sci ences, Pol ish Acad emy of Sci ences, Twarda 51/55, 00-818 Warszawa, Po land Siuda R. and Kruszewski £. (2013) Re cently formed sec ond ary cop per min er als as in di ca tors of geo chem i cal con di tions in an aban doned mine in Radzimowice (SW Po land). Geo log i cal Quar terly, 57 (4): 583-600, doi: 10.7306/gq.1114An oc cur rence of twelve re cently formed sec ond ary cop per min er als (SCM) was ob served in un der ground work ings of an aban doned Cu-As-Au mine in Radzimowice. The min er als, mainly sul phate spe cies, were iden ti fied us ing Pow der X-Ray Diffrac tion (PXRD), scan ning elec tron mi cro scope with en ergy dispersive spec tros copy sys tem (SEM-EDS) and elec tron microprobe anal y sis with wave length-dispersive spec trom e try sys tem (EPMA-WDS) meth ods. The SCM of Radzimowice form the fol low ing as sem blages: paragenesis I is char ac ter ized by langite, posnjakite, brochantite and devilline. These miner als crys tal lise di rectly from pH 6.0-7.0 mine wa ters. Paragenesis II also com prises hy drous cop per sulphates (HCS), and in ad di tion con tains na tive cop per, cu prite, ferrihydrite and gyp sum. Sec ond ary HCS mainly crys tal lise as prod ucts of re actions of sul phate-rich mine wa ters with na tive cop per and cu prite. The pH of these wa ters var ies from ~5.0 to 6.0. The III paragenesis is dom i nated by woodwardite, as so ci ated with vari able amounts of chalcoalumite and amor phous Cu-Al sulphates. Ac cu mu la tions of woodwardite oc cur in the zones where Al-and sul phate-rich acid mine wa ters (pH ~2.5-3.0) mix with neu tral wa ters (pH 6.5-7.0). Paragenesis IV is rare, dom i nated by chrysocolla, co ex ist ing with small amounts of mottramite and goethite. This as sem blage formed as a re sult of mo bi li za tion of sil ica re leased dur ing de com po si tion of rock-form ing aluminosilicates at tacked by acid mine wa ters.

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Effects of selected water chemistry variables on copper pitting propagation in potable water

Cited by 40 publications

References 44 publications

Artificial Pit Study on Effects of Bulk Solution Composition Changes on Copper Pitting Propagation in Synthetic Potable Waters

Artificial Pit Study on Effects of Bulk Solution Composition Changes on Copper Pitting Propagation in Synthetic Potable Waters

Chlorine Reduction Kinetics and its Mass Balance in Copper Premise Plumbing Systems During Corrosion Events

Recently forming secondary copper minerals as indicators of geochemical conditions in an abandoned mine in Radzimowice (SW Poland)

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