In-situ identification of iron electrocoagulation speciation and application for natural organic matter (NOM) removal

Dubrawski, Kristian L.; Mohseni, Madjid

doi:10.1016/j.watres.2013.06.021

Cited by 74 publications

(35 citation statements)

References 40 publications

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“…Beyond physical removal, as the pH drops, E. coli inactivation may play an increasingly important role during EC. For example, the oxidation rate of ferrous to ferric iron is slower at lower pH (Equation (3) [50]), resulting in a greater prevalence of reactive iron species [12,51]. Thus, lower pH leads to higher ferrous iron concentrations, which are capable of inactivating E. coli and viruses due to ferrous iron oxidation [8,28,51,52].…”

Section: Impact Of Enhanced Ec-eo For E Coli Mitigationmentioning

confidence: 99%

Electrocoagulation as a Pretreatment for Electroxidation of E. coli

Lynn

Heffron

Mayer

2019

Water

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Insufficient funding and operator training, logistics of chemical transport, and variable source water quality can pose challenges for small drinking water treatment systems. Portable, robust electrochemical processes may offer a strategy to address these challenges. In this study, electrocoagulation (EC) and electrooxidation (EO) were investigated using two model surface waters and two model groundwaters to determine the efficacy of sequential EC-EO for mitigating Escherichia coli. EO alone (1.67 mA/cm2, 1 min) provided 0.03 to 3.9 logs mitigation in the four model waters. EC alone (10 mA/cm2, 5 min) achieved ≥1 log E. coli mitigation in all model waters. Sequential EC-EO did not achieve greater mitigation than EC alone. To enhance removal of natural organic matter, the initial pH was decreased. Lower initial pH (pH 5–6) improved E. coli mitigation during both stages of EC-EO. EC-EO also had slightly greater E. coli mitigation than EC alone at lower pH. However, EO alone provided more energy efficient E. coli mitigation than either EC or EC-EO.

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Section: Impact Of Enhanced Ec-eo For E Coli Mitigationmentioning

confidence: 99%

Electrocoagulation as a Pretreatment for Electroxidation of E. coli

Lynn

Heffron

Mayer

2019

Water

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“…While some researchers have alluded to challenges with coagulant residuals2223, a systematic investigation is lacking as to how operating and environmental conditions influence these residuals. Aluminum and iron have secondary Maximum Contaminant Levels (MCLs) for drinking water of 0.2 and 0.3 mg/L, respectively24.…”

mentioning

confidence: 99%

Removal of trace metal contaminants from potable water by electrocoagulation

Heffron

Marhefke

Mayer

2016

Sci Rep

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This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency.

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“…Our results add to the growing body of literature showing that electrocoagulation can effectively remove a range of contaminants including organic matter [27,30,60], microorganisms [50,61], boron and other inorganic constituents [21]. Moreover since elevated current densities (and concomitantly short residence times) are possible, compact and portable units can be fabricated for easy field-deployment suggesting that electrocoagulation may be a facile choice for flowback/produced water treatment.…”

Section: Discussionmentioning

confidence: 57%