Carbon Tetrachloride Reduction by Fe2+,S2-, and FeS with vitamin B12 as Organic Amendment

Assaf-Anid, Nada; Lin, Kun-Yu

doi:10.1061/(asce)0733-9372(2002)128:1(94)

Cited by 25 publications

(15 citation statements)

References 39 publications

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“…The stochiometry of this reaction, however, needs to be established. Nevertheless the degradation efficiency of FP1-stabilized nanoparticles was quite high and comparable to that obtained by Assaf-Anid and Kun-Yu [17] for carbon tetrachloride. However, it must be emphasized that in contradistinction to the present study, Assaf-Anid and Kun-Yu used higher concentrations (70-500 mM) of FeS, alkaline pH and an organic amendment to get increased rates of degradation.…”

Section: Lindane Degradation Using Fes Nanoparticlessupporting

confidence: 51%

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Degradation of lindane from aqueous solutions using iron sulfide nanoparticles stabilized by biopolymers

Paknikar

Nagpal

Pethkar

et al. 2005

Science and Technology of Advanced Materials

134

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Lindane (g-hexachlorocyclohexane) is an organochlorine pesticide and a Persistent Organic Pollutant (POP). Lindane residues have been detected in drinking water sources and development of viable methods for their removal is a global priority. Iron based nanomaterials have been shown to effectively transform chlorinated organic compounds. However, their uses in the treatment of drinking water and beverages have toxicity concerns. In the present study, FeS nanoparticles were synthesized by the wet chemical method and were stabilized using a polymer from the basidiomycetous fungus, Itajahia sp. The stabilized nanoparticles could degrade lindane (5 mg/l) with an efficiency of 94% in 8 h. In a subsequent microbiological treatment, residual lindane, its partially degraded intermediates as well as the stabilizing polymer could be completely degraded in 1 h. The latter process facilitated aggregation of FeS, which could be easily removed by filtration. This novel integrated nano-biotechnological method holds the promise of providing an efficient, safe, and cost-effective solution to the problem of removal of chlorinated pollutants from water sources. q

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Section: Lindane Degradation Using Fes Nanoparticlessupporting

confidence: 51%

“…Therefore, the combination of iron and sulfide, e.g. as FeS, could considerably enhance reductive degradation of halogenated compounds [17,18]. Stability of FeS in aqueous media, near neutral pH values is an added advantage in their practical use.…”

Section: Introductionmentioning

confidence: 99%

Degradation of lindane from aqueous solutions using iron sulfide nanoparticles stabilized by biopolymers

Paknikar

Nagpal

Pethkar

et al. 2005

Science and Technology of Advanced Materials

134

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“…Reduced enzyme cofactors of the anaerobic microorganisms have been implicated as the catalyst of the observed transformations. The heat stable cobalt-containing cofactor, vitamin B 12 , was shown to directly catalyze the dechlorination of CT when supplied with an appropriate reducing agent such as Ti(III)-citrate or hydrogen sulfide (Assaf-Anid & Lin 2002;Gantzer & Wackett 1991;Krone et al 1991;Tanaka 1997). Vitamin B 12 is a common cofactor of strict anaerobes, especially those involved in C 1 metabolism.…”

Section: Introductionmentioning

confidence: 98%

Enhancement of anaerobic carbon tetrachloride biotransformation in methanogenic sludge with redox active vitamins

Guerrero–Barajas

Field

2005

Biodegradation

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Carbon tetrachloride (CT) is an important groundwater pollutant which is only subject to biotransformation in the absence of oxygen. The anaerobic biotransformation of CT is influenced by electron shuttling compounds. The purpose of this study was to evaluate the impact of redox active vitamins on CT (100 microM) metabolism in a methanogenic sludge consortium (0.5 g VSS l(-1)) supplied with volatile fatty acids as electron donor (0.2 g COD l(-1)). The redox active vitamins, tested at concentrations ranging from 0.5 to 20 microM, were riboflavin (RF) and two forms of vitamin B12, cyanocobalamin (CNB12) and hydroxycobalamin (HOB12), and these were compared with a redox mediating quinone, anthraquinone-2,6-disulfonate (AQDS). Substoichiometric concentrations of RF, CNB12, HOB12 at molar ratios of vitamin: CT as low as 0.005 significantly increased rates of CT-bioconversion. These are the lowest molar ratios of vitamin B12 reported having an impact on dechlorination. Additionally, this study constitutes the first report of RF having a role in reductive dechlorination. At molar ratios of 0.1 vitamin: CT, RF, CNB12, HOB12 increased the first order rate constant of CT bioconversion by 4.0-, 13.3-and 13.6-fold, respectively. The redox active vitamins also enhanced the rates of abiotic CT conversion in heat killed sludge treatments, but the rates were approximately 4- to 5-fold lower than the corresponding vitamin enhanced rates of biological CT conversion. The addition of CNB12 or HOB12 to the live methanogenic sludge consortium increased the yield of inorganic chloride (Cl-) from CT-converted. Chloroform was a transient intermediate in CNB12 or HOB12 supplemented cultures. In contrast, the addition of RF increased the yield of chloroform from CT-converted. Taken as a whole the results clearly demonstrate that very low concentrations of redox active vitamins could potentially play an important role in accelerating the anaerobic the bioremediation of CT as well as influencing the proportions of biotransformation products formed.

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“…However, there are measurable differences between buffered (pH = 8.8) and unbuffered (pH ∼7.2) dithionite treatments in the type of iron present, with the sediment treated with buffered dithionite having a higher Fe 2+ /Fe 3+ ratio and also retaining strongly adsorbed FeS-like surface species even after copious washing with deionized water. FeS has been shown to reduce carbon tetrachloride, [40,41] hexachloroethane, [42] trichloroethylene and tetrachloroethylene. [42] The presence of FeS, along with Fe 3 O 4 on Pantex aquifer sediment surfaces after dithionite treatment, supports the effectiveness of this treatment for reduction of royal demolition explosive, hexahydro-1,3,5-trinitro-1,3,5-triazene (RDX) [21] in the aquifer matrix.…”

Section: Discussionmentioning

confidence: 99%

Effect of sodium dithionite on the surface composition of iron‐containing aquifer sediment

Langell

Kadossov

Boparai

et al. 2009

Surface & Interface Analysis

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Carbon Tetrachloride Reduction by Fe2+,S2-, and FeS with vitamin B12 as Organic Amendment

Cited by 25 publications

References 39 publications

Degradation of lindane from aqueous solutions using iron sulfide nanoparticles stabilized by biopolymers

Degradation of lindane from aqueous solutions using iron sulfide nanoparticles stabilized by biopolymers

Enhancement of anaerobic carbon tetrachloride biotransformation in methanogenic sludge with redox active vitamins

Effect of sodium dithionite on the surface composition of iron‐containing aquifer sediment

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