Cation and Anion Retention by Natural and Synthetic Allophane and Imogolite

Clark, C.J.; McBride, Murray B.

doi:10.1346/ccmn.1984.0320407

Cited by 92 publications

(93 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The isolation and characterization of the natural samples has been described elsewhere (Clark and McBride, 1984). Allophanic clay fractions (<2 /~m) from three field-moist volcanic ash soils, Egmont (Eg), l Present address: Ruakura Soil and Plant Research Station, Hamilton, New Zealand.…”

Section: Methodsmentioning

confidence: 99%

“…Synthetic allophanes with SIO2/A1203 ratios of 1.10, 1.34, 1.67 and synthetic imogolite were prepared and characterized as before (Clark and McBride, 1984). Dry samples were used throughout, and all results are expressed on a 150~ oven-dry clay basis.…”

Section: Methodsmentioning

confidence: 99%

“…Based on the amount of "active" AI--OH in imogolite, 100 mmole/kg (Clark and McBride, 1984), combined with assumptions of a 13-A external radius and 28 edge-sorption sites/tubule (Farmer and Fraser, 1978), Co and Cu adsorption of ~30 mmole/kg (Figures 5B and 6B) represents 8 ions/tube, or an average intermetal separation of 20 A for ions on terminal edge sites. Although the solubility product of malachite (Cuz(OH)2CO3) wag exceeded at the highest pHs (Figure 4), the ESR evidence (see below) suggests that all adsorbed Cu 2 § was bound in a monomeric form at wellseparated surface sites.…”

Section: Adsorption As a Function Of Ph And Concentrationmentioning

confidence: 99%

See 2 more Smart Citations

Chemisorption of Cu(II) and Co(II) on Allophane and Imogolite

Clark

McBride

1984

Clays and clay miner.

Self Cite

View full text Add to dashboard Cite

Abstract--Adsorption of Cu 2+ and Co 2+ by synthetic imogolite, synthetic allophanes with a range of SiO2/ A1203 ratios, and allophanic clay fractions from volcanic ash soils was measured in an ionic medium of 0.05 M Ca(NO3) 2. The effect ofpH (and metal concentration) on adsorption was qualitatively similar for the synthetic and natural allophanes with relatively minor changes in behavior caused by variable SLOE/ A1203 ratios. Cu and Co were chemisorbed by aUophane at pH 5.0-5.5 and 6.9-7.2 (pH values for 50% adsorption level), respectively, with concomitant release of 1.6-1.9 protons/metal ion adsorbed. Quantitatively, adsorption by imogolite was less than that by the allophanes, presumably because of fewer sites available for chemisorption on the tubular structure of imogolite. Electron spin resonance studies of the imogolite and allophanes revealed that Cu 2 § was adsorbed as a monomer on two types of surface sites. The preferred sites were likely adjacent A1OH groups binding Cu 2+ by a binuclear mechanism; weaker bonding occurred at isolated A1OH or SiOH groups. These chemisorbed forms of Cu E+ were readily extracted by EDTA, CHaCOOH, and metals capable of specific adsorption, but were not exchangeable. In addition, the H20 and/or OH-ligands of chemisorbed Cu E+ were readily displaced by NH3, with the formation of ternary Cu-ammonia-surface complexes.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Adsorption As a Function Of Ph And Concentrationmentioning

confidence: 99%

See 1 more Smart Citation

Chemisorption of Cu(II) and Co(II) on Allophane and Imogolite

Clark

McBride

1984

Clays and clay miner.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ion adsorption studies have been used to determine the total amount of positive and negative charge on synthetic and natural samples of imogolite and allophane as a function of pH (Perrott, 1977;GonzalesBatista et aL, 1982;Theng, 1982;Clark and McBride, 1984;Wada, 1984;Suet al, 1992). The electrophoretic mobility has also been determined as a function of pI-I and ionic strength for similar materials (Escudey and Galindo, 1983;Escudey et al, 1986;Horikawa, 1975 Copyright 9 1992, The Clay Minerals Society nium bromide (Greenland and Quirk, 1962) and paraquat (Knight and Tomlinson, 1967) on imogolite and for alkyl ammonium cations on allophane or soils containing both allophane and imogolite (Birrell, 1961;Wada and Tange, 1984).…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Cations on Imogolite and their Effect on Surface Charge Characteristics

Harsh

Traina

Boyle

et al. 1992

Clays and clay miner.

View full text Add to dashboard Cite

Abstract--Noncrystalline aluminosilicates termed allophane and imogolite are common constituents of spodosols, soils derived from volcanic ash, and many inceptisols. The surface charge characteristics of their synthetic analogues may be used to better understand their ion retention properties. In this study, we determined the point of zero salt effect (PZSE) by potentiometric titration of allophanes with A1/Si ratios of 1.12, 1.52, and 2.04 and of imogolite with an A1/Si ratio of 2.02. We also used microelectrophoresis to determine the point of zero charge (PZC) at the particle shear plane for the same materials in C1 solutions of Li, Na, Cs, and tetramethyl ammonium. The PZSE decreased with decreasing A1/Si ratio for the allophanes, but the imogolite PZSE was much lower than that of the allophane with 2.04 A1/Si. The PZC was always higher than the PZSE of the same material, especially for imogolite. The results are best explained if cations reside within the hollow tubes ofimogolite. This conclusion is supported by a fluorescence study that showed that only quenchers smaller than the inner diameter of the imogolite tube could fully quench Ce-imogolite.

show abstract

“…proto-imogolite allophane (PIA), that are known to occur in Podzol Bs horizons (39,40). PIA contribute significantly to the anion adsorption capacity in Podzol B horizons due to their high point of zero charge (41,42).…”

Section: )mentioning

confidence: 99%

Arsenic and Chromium Partitioning in a Podzolic Soil Contaminated by Chromated Copper Arsenate

Hopp

Nico

Marcus

et al. 2008

Environ. Sci. Technol.

View full text Add to dashboard Cite

This research combined the use of selective extractions and x-ray spectroscopy to examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e. proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/Cr(III) solid phase that formed upon the Fe(II) application (25-50%) and a recalcitrant phase (50-75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solid phases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.

show abstract

Cation and Anion Retention by Natural and Synthetic Allophane and Imogolite

Cited by 92 publications

References 27 publications

Chemisorption of Cu(II) and Co(II) on Allophane and Imogolite

Chemisorption of Cu(II) and Co(II) on Allophane and Imogolite

Adsorption of Cations on Imogolite and their Effect on Surface Charge Characteristics

Arsenic and Chromium Partitioning in a Podzolic Soil Contaminated by Chromated Copper Arsenate

Contact Info

Product

Resources

About