Quantitative Assay of Minerals for Fe<sup>2+</sup> and Fe<sup>3+</sup> Using 1,10-Phenanthroline: III. A Rapid Photochemical Method

Komadel, Peter; Stucki, Joseph W.

doi:10.1346/ccmn.1988.0360415

Cited by 165 publications

(95 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…were used for the determination of total structural Fe and Fe(I1) contents by the method of Komadel and Stucki (1988). The dissolved Fe content in the treatment solutions was determined by atomic absorption.…”

Section: Methodsmentioning

confidence: 99%

Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces

Taylor

2000

Clays and clay miner.

View full text Add to dashboard Cite

Abstract--Chromium(VI) in the environment is of particular concern because it is toxic to both plants and animals, even at low concentrations. As a redox-sensitive element, the fate and toxicity of chromium is controlled by soil reduction-oxidation (redox) reactions, ln-situ remediation of chromium combines reduction of Cr(VI) to Cr(III) and immobilization of chromium on mineral surfaces. In this study, Fetich smectite, montmorillonite, illite, vermiculite, and kaolinite were examined to determine reactivity in sorption-reduction of Cr(VI). The clays were compared to forms that were reduced by sodium dithionite. Clays containing Fe(lI) efficiently removed soluble Cr(VI) from solution. Chromium K-edge X-ray absorption near edge structure (XANES) suggested that clays containing Fe(II) reduced Cr(VI) to Cr(III), immobilizing Cr at the clay/water interface. Adsorption of Cr(VI) by the Fe(II)-containing clay was a prerequisite for the coupled sorption-reduction reaction. Sodium dithionite added directly to aqueous suspensions of non-reduced clays reduced Cr(VI) to Cr(III), but did not immobilize Cr on clay surfaces. The capacity of clays to reduce Cr(VI) is correlated with the ferrous iron content of the clays. For dithionite-reduced smectite, the exchangeable cation influenced the sorption reaction, and thus it also influenced the coupled sorption-reduction reaction of Cr(VI). The pH of the aqueous system affected both the amount of Cr(VI) reduced to Cr(III) and the partition of Cr(llI) between aqueous and adsorbed species. A plot of pH vs. amount (adsorption envelope) adsorbed for the coupled sorption-reduction reaction of Cr by reduced smectite exhibited a similar pattern to that of typical anion-sorption.

show abstract

Section: Methodsmentioning

confidence: 99%

Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces

Taylor

2000

Clays and clay miner.

View full text Add to dashboard Cite

show abstract

“…The percolating solution was collected daily through 13 drainage ports at the reactor base and the pH, redox potential and iron and copper concentrations were quantified. The iron and copper concentration measurements were done using the 1,10-phenanthroline colorimetric method (Komadel and Stucki, 1988) and atomic absorption spectroscopy, respectively. Therefore the liquid distribution in run A was different to the results of the later runs (B and C) for both samples.…”

Section: Mri Cellmentioning

confidence: 99%

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

et al. 2014

View full text Add to dashboard Cite

Heap bioleaching performance is dependent on the contacting of the leach solution with the ore bed, hence on the system hydrodynamics. In this study two experimental setups were used to examine hydrodynamics associated with irrigation from a single drip emitter, one of the most common methods of heap irrigation. A specialist magnetic resonance imaging (MRI) method which is insensitive to the metal content of the ore was used to examine the liquid flow into an ore bed in the immediate vicinity of an irrigation point. The distribution of liquid in, microbial colonisation of and mineral recovery from a bioleach of a large scale 132 kg "ore slice" were subsequently monitored using sample ports positioned along the breadth and height of the reactor. In both systems the lateral movement of the liquid increased with bed depth, though preferential flow was evident. The majority of the liquid flow was in the region directly below the irrigation point and almost no liquid exchange occurred in the areas of lowest liquid content at the upper corners of the bed in which fluid exchange was driven by capillary action. The MRI studies revealed that the liquid distribution was unchanging following an initial settling of the ore bed and that, at steady state, the majority (~60%) of the liquid flowed directly into established large channels. The limited lateral movement of the liquid had a significant impact on the local leaching efficiencies and microbial colonisation of the ore with cell concentrations in the regions of lowest liquid content lying below the detection limit. Hence poor lateral liquid distribution with drip irrigation, and the associated impact on colonisation was identified as a significant disadvantage of this irrigation approach. Further, the need to optimise fluid exchange throughout the ore bed was identified as key for optimisation of leaching performance.

show abstract

“…Reduced [Fe(II)] and total Fe (FeT) were measured in each clay using a 1,10-phenanthroline-colorimetric method (Table 1) (Komadel and Stucki, 1988). The content of oxidized Fe [Fe(III)] was deduced by difference.…”

Section: Reduced-reoxidized Form Aliquots Of Reduced-claymentioning

confidence: 99%

Adsorption Kinetics of Pentachloroethane by Iron-Bearing Smectites

Cervini-Silva

Stucki

et al. 2000

Clays and clay miner.

View full text Add to dashboard Cite

Abstract--The oxidation state of structural Fe greatly alters surface chemistry, which may have a large influence on clay-organic interactions. The effect of structural-iron oxidation state on chlorinated hydrocarbons at the clay-water interface was examined. Pentachloroethane (5CA) was reacted with oxidized, reduced, and reoxidized forms of three different smectites: montmorillonite, ferruginous smectite, and nontronite in aqueous suspension under controlled-atmosphere conditions. Pentachloroethane was found to adsorb at different rates for the three smectites. A series of 5CA-adsorption rate constants in the presence of these clays showed a strong correlation with the Fe(II) content of the clay (r 2 = 0.98). The clay surface behaves as a Br0nsted base and promotes 5CA dehydrochlorination. The adsorption kinetics at the clay-water interface were described by the formation of a precursor complex prior to 5CA dehydrochlorination.

show abstract

Quantitative Assay of Minerals for Fe²⁺ and Fe³⁺ Using 1,10-Phenanthroline: III. A Rapid Photochemical Method

Cited by 165 publications

References 8 publications

Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces

Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

Adsorption Kinetics of Pentachloroethane by Iron-Bearing Smectites

Contact Info

Product

Resources

About

Quantitative Assay of Minerals for Fe2+ and Fe3+ Using 1,10-Phenanthroline: III. A Rapid Photochemical Method

Cited by 165 publications

References 8 publications

Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces

Chromate Removal by Dithionite-Reduced Clays: Evidence from Direct X-Ray Adsorption Near Edge Spectroscopy (XANES) of Chromate Reduction at Clay Surfaces

MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching micro-organisms

Adsorption Kinetics of Pentachloroethane by Iron-Bearing Smectites

Contact Info

Product

Resources

About

Quantitative Assay of Minerals for Fe²⁺ and Fe³⁺ Using 1,10-Phenanthroline: III. A Rapid Photochemical Method