Electrochemical removal and recovery of iron from groundwater using non-corrosive electrodes

Nguyễn, Văn Khánh; Ahn, Yeonghee

doi:10.1016/j.jenvman.2018.01.046

Cited by 9 publications

(3 citation statements)

References 14 publications

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“…Spent nZVI precipitates could be collected and recycled to Fe 0 and, when FeCO 3 is present, to reduced one-carbon compounds (CO, CH 4 ) through reductive calcination ( Lux et al, 2019 ). Soluble Fe 2+ can also be electrochemically recovered as goethite (FeOOH) ( Nguyen and Ahn, 2018 ) and may be recycled together with the other precipitates. Carbon monoxide (CO) could be looped back into the chain elongation process as additional electron and carbon source.…”

Section: Discussionmentioning

confidence: 99%

nZVI Impacts Substrate Conversion and Microbiome Composition in Chain Elongation From D- and L-Lactate Substrates

Contreras-Dávila

Esveld

Buisman

et al. 2021

Front. Bioeng. Biotechnol.

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Medium-chain carboxylates (MCC) derived from biomass biorefining are attractive biochemicals to uncouple the production of a wide array of products from the use of non-renewable sources. Biological conversion of biomass-derived lactate during secondary fermentation can be steered to produce a variety of MCC through chain elongation. We explored the effects of zero-valent iron nanoparticles (nZVI) and lactate enantiomers on substrate consumption, product formation and microbiome composition in batch lactate-based chain elongation. In abiotic tests, nZVI supported chemical hydrolysis of lactate oligomers present in concentrated lactic acid. In fermentation experiments, nZVI created favorable conditions for either chain-elongating or propionate-producing microbiomes in a dose-dependent manner. Improved lactate conversion rates and n-caproate production were promoted at 0.5–2 g nZVI⋅L–1 while propionate formation became relevant at ≥ 3.5 g nZVI⋅L–1. Even-chain carboxylates (n-butyrate) were produced when using enantiopure and racemic lactate with lactate conversion rates increased in nZVI presence (1 g⋅L–1). Consumption of hydrogen and carbon dioxide was observed late in the incubations and correlated with acetate formation or substrate conversion to elongated products in the presence of nZVI. Lactate racemization was observed during chain elongation while isomerization to D-lactate was detected during propionate formation. Clostridium luticellarii, Caproiciproducens, and Ruminococcaceae related species were associated with n-valerate and n-caproate production while propionate was likely produced through the acrylate pathway by Clostridium novyi. The enrichment of different potential n-butyrate producers (Clostridium tyrobutyricum, Lachnospiraceae, Oscillibacter, Sedimentibacter) was affected by nZVI presence and concentrations. Possible theories and mechanisms underlying the effects of nZVI on substrate conversion and microbiome composition are discussed. An outlook is provided to integrate (bio)electrochemical systems to recycle (n)ZVI and provide an alternative reducing power agent as durable control method.

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Section: Discussionmentioning

confidence: 99%

nZVI Impacts Substrate Conversion and Microbiome Composition in Chain Elongation From D- and L-Lactate Substrates

Contreras-Dávila

Esveld

Buisman

et al. 2021

Front. Bioeng. Biotechnol.

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“…Currently, these methods have limitations such as toxic by-product formation, large space requirement, high energy consumption, low treatment efficiency, and chemical storage requirement. In recent years, previous reports on electrochemical studies have shown that electrochemical treatment can effectively remove contaminants or pathogens from the environment [11][12][13]. Electrochemical disinfection has gained increasing attention due to its ability to inactivate and remove various living organisms and pathogens from water [13,14].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Disinfection of Simulated Ballast Water Using RuO2-TiO2/Ti Electrode

Annamalai

Futalan

Ahn

2022

IJERPH

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The present work investigated the treatment of ballast water via electrochemical disinfection using a RuO2-TiO2/Ti electrode. Batch tests were conducted with simulated ballast water containing Escherichia coli as an indicator organism. The effect of varying NaCl concentrations (1%, 2%, and 3%; w/v) and current densities (0.3, 1.0, 2.0, and 3.0 mA/cm2) on the inactivation of E. coli was examined. Results showed higher disinfection efficiency of E. coli was obtained at higher NaCl concentration and current density. Complete inactivation of E. coli was attained within 2 and 1 min at 0.3 and 1 mA/cm2, respectively, under 3% NaCl concentration. Meanwhile, complete disinfection at 1 and 2% NaCl concentrations was observed in 6 and 2 min, respectively, using a current density of 0.3 mA/cm2. The 100% inactivation of E. coli was achieved with an energy consumption in the range of 2.8 to 2.9 Wh/m3 under the NaCl concentrations at 1 mA/cm2 and 1 min of electrolysis time. The complete disinfection attained within 1 min meets the D-2 standard (<250 CFU E. coli/100 mL) of ballast water under the International Maritime Organization. The values of energy consumption of the present work are lower than previous reports on the inactivation of E. coli from simulated ballast water.

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“…Soluble Fe 2+ can also be electrochemically recovered as goethite (FeOOH) (Nguyen and Ahn, 2018) and may be recycled together with the other precipitates. Carbon monoxide (CO) could be looped back into the chain elongation process as additional electron and carbon source.…”

Section: Discussionmentioning

confidence: 99%

Lactate-based chain elongation : Poduction and separation of medium-chain carboxylates from complex organic residues

Dávila¹,

Carlos²

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The production of biochemicals from renewables through biorefinery processes is important to reduce the anthropogenic impact on the environment. Chain elongation processes based on microbiomes have been successfully developed to produce medium-chain carboxylates (MCC) from organic waste streams. Yet, the sustainability of chain elongation can still be improved by reducing the use of electron donors and additional chemicals. This work aimed to couple lactate production and subsequent chain elongation to decrease chemicals input such as electron donors and hydroxide for pH control in repeated-batch food waste fermentation. Food waste with adjusted pH was used as substrate and fermentation proceeded without pH control. During fermentation, lactate was first formed through the homolactic pathway and then converted to carboxylates, mainly n-butyrate and n-caproate. The highest n-caproate carbon selectivities (mmol C•mmol Ccarboxylates -1 ) and production rates were 38% and 4.2 g COD•L -1 •d -1 , respectively. Hydroxide input was reduced over time to a minimum of 0.47 mol OH -•mol MCC -1 or 0.79 mol OH -•kg CODcarboxylate -1 . Lactate was a key electron donor for chain elongation and its conversion was observed at pH as low as 4.3. The microbiome enriched in this work was dominated by Lactobacillus spp. and Caproiciproducens spp.. The high abundance of Caproiciproducens spp. and their co-occurrence with Lactobacillus spp. suggest Caproiciproducens spp. used lactate as electron donor for chain elongation. This work shows the production of n-caproate from food waste with decreased use of hydroxide and no use of exogenous electron donors.

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Electrochemical removal and recovery of iron from groundwater using non-corrosive electrodes

Cited by 9 publications

References 14 publications

nZVI Impacts Substrate Conversion and Microbiome Composition in Chain Elongation From D- and L-Lactate Substrates

nZVI Impacts Substrate Conversion and Microbiome Composition in Chain Elongation From D- and L-Lactate Substrates

Electrochemical Disinfection of Simulated Ballast Water Using RuO2-TiO2/Ti Electrode

Lactate-based chain elongation : Poduction and separation of medium-chain carboxylates from complex organic residues

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