Adsorption of Aqueous Cobalt Ethylenediaminetetraacetate by δ-Al2O3

Girvin, D.C.; Gassman, Paul L.; Bolton, H.

doi:10.2136/sssaj1993.03615995005700010010x

Cited by 93 publications

(62 citation statements)

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“…The EDTA is again exhibiting typical anionic adsorption behavior; however, less adsorption is observed at lower pH values than was observed in the nickel experiment ( Figure 5.7). Girvin et al (1993) observed similar behavior during the study of Co+ 2 -EDTA adsorption onto 8-A1 2 0 3 . Note that adsorption of Ni 2 ÷ onto iron oxides is nearly identical to that of Co 2 " (Coughlin and Stone 1995).…”

Section: U-edta Systemsupporting

confidence: 65%

“…Note that adsorption of Ni 2 ÷ onto iron oxides is nearly identical to that of Co 2 " (Coughlin and Stone 1995). In the study of Girvin et al (1993), the adsorption of EDTA was significantly less than when Co 2 ' was present. It was proposed that the EDTA species that were adsorbed in the absence of Co0 2 were Al-EDTA° and Al-HEDTA° formed by dissolution of the 6 Al,0 3 .…”

Section: U-edta Systemmentioning

confidence: 85%

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Radionuclide-Chelating Agent Complexes in Low-Level Radioactive Decontamination Waste; Stability, Adsorption and Transport Potential

Serne¹,

Cantrell²,

Lindenmeier³

et al. 2002

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Section: U-edta Systemsupporting

confidence: 65%

Section: U-edta Systemmentioning

confidence: 85%

Radionuclide-Chelating Agent Complexes in Low-Level Radioactive Decontamination Waste; Stability, Adsorption and Transport Potential

Serne¹,

Cantrell²,

Lindenmeier³

et al. 2002

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“…Thus, for pH < 7, Co adsorption decreased with decreasing pH and was not strictly ligand-like. A similar pattern of adsorption on ~-A1203 was observed for equal molar Co(II)EDTA for pH 5 to 9.5 over a wide range of sorbate concentrations and solid-to-sorbate ratios (Girvin et al 1993). Metal adsorption in equalmolar Cd-, Cu-, Ni-, Pb-and Zn-EDTA suspensions of ~-A1203 (pHpz~ = 9.2), was ligand-like for Ni and Cu and mixed cation-ligand-like for Cd, Pb and Zn (Bowers and Huang 1986).…”

Section: Introductionsupporting

confidence: 67%

Adsorption of Nitrilotriacetate (NTA), Co and CoNTA By Gibbsite

Girvin

Gassman

Bolton

1996

Clays and clay miner.

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Abstract--Adsorption of Co 2 § nitrilotriacetic acid (NTA) and equal-molar Co 2 § and NTA by a low surface area (LSA) commercial gibbsite (3.5 m 2 g-~) was investigated in batch as a function of pH (4.5 to 10.5), adsorbate (0.5 to 10 txM) and adsorbent (0.5 to 75 g L ~) concentrations and ionic strength (0.01 to 1 M NaC104). The adsorption of Co 2 § (Co-only) and the acid form of NTA (NTA-only) by gibbsite in 0.01 M NaC104 exhibit cation-like and anion-like adsorption edges, respectively. For the equal-molar CoNTA chelate, Co and NTA adsorption edges were similar but not identical to the Co-only and NTAonly edges. Differences suggest the existence of a ternary CoNTA surface complex with the Co in the intact chelate coordinated to surface hydroxyls. NTA-only adsorption was insensitive to ionic strength variation, indicating weak electrostatic contributions to surface coordination reactions. This is consistent with the formation of inner-sphere surface NTA complexes and ligand exchange reactions in which monodentate, bidentate and binuclear NTA surface complexes form. Cobalt adsorption increases (edge shifts to lower pH by 1 pH unit) on LSA gibbsite as ionic strength increases from 0.01 to 1 M NaC104. For the same ionic strength change, a similar shift in the Co-only edge was observed for another commercial gibbsite (16.8 m 2 g 1); however, no change was observed for ~-A1203. Ionic strength shifts in Co 2+ adsorption by gibbsite were described as an outer-sphere CoOH § surface complex using the triplelayer model. Results suggest that, at waste disposal sites where 6~ and NTA have been co-disposed, NTA will not promote ligand-like adsorption of Co for acid conditions, but will reduce cation-like adsorption for basic conditions. Thus, where gibbsite is the dominant mineral sorbent, NTA will not alter 6~ mobility in acidic pore waters and groundwaters; however, NTA could enhance 6~ mobility where alkaline conditions prevail, unless microbial degradation of the NTA occurs.

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“…For example, cobalt adsorption on geologic materials has been shown to decrease by the presence citric acid (Khan et al 1996), EDTA (Wilding and Rhodes 1963;Cantrell and Serne 1993;Girvin et al 1993;Jardine et al 1993;Szecsody et al 1994Szecsody et al , 1998Jardine and Taylor 1995;Zachara et al 1995aZachara et al , 1995bKhan et al 1996;Fendorf et al 1999), hydroxyethylethylenediaminetriacetate acid (HEDTA) , diethylenetriaminepentaacetic acid (DTPA) (Khan et al 1996), cyclohexanediaminetetraacetic acid (CDTA) (Khan et al 1996), and nitrilotriacetic acid (NTA) . This decrease in cobalt adsorption is typically caused by the formation of anionic cobalt complexes at near neutral and basic pH conditions, which do not readily adsorb on mineral surfaces at basic pH values.…”

Section: A142 Cobaltmentioning

confidence: 99%

“…Since the early 1990s, research has focused primarily on understanding the mechanisms controlling the aqueous speciation and complexation, oxidation/reduction, and sorption of cobalt in the presence of EDTA at the solution/mineral interface (Girvin et al 1993;Jardine et al 1993;Szecsody et al 1994Szecsody et al , 1998Jardine and Taylor 1995;Zachara et al 1995aZachara et al , 1995bZachara et al , 2000Gorby et al 1998;Fendorf et al 1999). This research was prompted by the enhanced migration of 60 Co reported at some DOE sites, such as the Hanford Site (Fruchter et al 1984(Fruchter et al , 1985 and Oak Ridge National Laboratory (Means et al 1976(Means et al , 1978a).…”

Section: A142 Cobaltmentioning

confidence: 99%

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

Cantrell¹,

Zachara²,

Dresel³

et al. 2007

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Companion reports that review other subject matter areas relevant to contaminant transport within the vadose zone beneath the SST WMAs, the IDF, and groundwater have been recently published. The specific subject areas include the geology of the SST WMAs iv contaminants released to the vadose zone exhibit a wide range of mobility behaviors. Many tank waste contaminants have been strongly retarded by adsorption and precipitation reactions (e.g., cesium, plutonium, americium, and europium), while others have remained mobile (e.g., technetium, nitrate, and selenium). Still others show variable, waste-specific behaviors (e.g., cesium [where sodium concentrations are very high], strontium, chromium, and uranium) that are closely tied to evolving composition of pore water in the sediments, and for chromium, a change in oxidation state. The temperature of in-ground tank waste has moderated by heat exchange with the subsurface sediment, and high concentrations of base (OH -) have been neutralized through reactions with sediment minerals and secondary mineral precipitation. Major geochemical features that may potentially affect the mobility of key contaminants of interest in the vadose zone include oxidation state, aqueous speciation, solubility, and adsorption reactions.Processes suspected of facilitating the far-field migration of immobile radionuclides, such as formation of stable aqueous complex formation and mobile colloids, were found to be potentially operative, but unlikely to occur in the field. An exception is the enhanced migration of cobalt-60 facilitated by the formation of highly stable aqueous-cyanide complexes. Certain fission-product oxyanions (e. • Adsorption is suppressed by large concentrations of tank waste anions (e.g., NO 3 -, OH -, and CO 3 2-)• Surface charge of clay-size minerals is negative and will therefore tend to repel anions• Unlike chromium, their less-soluble, less-mobile reduced forms are unstable in oxidizing environments.Laboratory studies conducted through PNNL's Vadose Zone Characterization Project and basic-science geochemical studies are expected to continue in partnership to provide information to further refine the conceptual model used for risk assessment modeling. Results of these studies can be used to help ascertain uncertainties associated with the refinement of the conceptual models for contaminant migration in the vadose zone beneath the single-shell tanks. Results can also provide improved parameterization, such as distribution coefficients (K d ), and mathematical constructs used by modelers to predict contaminant mobility under these conditions, and to decrease the degree of conservatism incorporated in these models.For various reasons, risk assessment models typically use various approximations to represent the conceptual model developed for the site. Adsorption is frequently approximated using empirical distribution coefficients (K d s). Although the use of empirical distribution coefficients can potentially lead to erroneous results under certain conditions where the...

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Adsorption of Aqueous Cobalt Ethylenediaminetetraacetate by δ-Al2O3

Cited by 93 publications

References 0 publications

Radionuclide-Chelating Agent Complexes in Low-Level Radioactive Decontamination Waste; Stability, Adsorption and Transport Potential

Radionuclide-Chelating Agent Complexes in Low-Level Radioactive Decontamination Waste; Stability, Adsorption and Transport Potential

Adsorption of Nitrilotriacetate (NTA), Co and CoNTA By Gibbsite

Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site

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