Surface loading effect on Cd and Zn sorption by kaolinite and montmorillonite from low concentration solutions

García‐Miragaya, J.; Cardenas, Rosa Maria Zambrano; Page, A. L.

doi:10.1007/bf00464780

Cited by 26 publications

(8 citation statements)

References 27 publications

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“…For example, Garcia-Miragaya et al (1986) reported that low concentrations of Cd and Zn were sorbed more strongly by kaolinite than montmorillonite possibly due to a higher proportion of weakly acidic edge sites being present on kaolinite surfaces. The authors found that adsorption was stronger for Cd than Zn and this was attributed to electrostatic attraction by permanent charge sites at the clay surface which is higher for Cd due to its larger ionic radius.…”

Section: Clay Contentmentioning

confidence: 99%

Factors influencing metal bioavailability in soils: preliminary investigations for the development of a critical loads approach for metals

Rieuwerts

Thornton

Farago

et al. 1998

Chemical Speciation & Bioavailability

487

232

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Section: Clay Contentmentioning

confidence: 99%

Factors influencing metal bioavailability in soils: preliminary investigations for the development of a critical loads approach for metals

Rieuwerts

Thornton

Farago

et al. 1998

Chemical Speciation & Bioavailability

487

232

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“…Adsorption-desorption of Zn in soils and waters can be affected by many factors, such as aging [2,3], adsorbent properties [4][5][6], and concentration [7,8]. However, studies on the effect of temperature on the adsorption reversibility have been very limited [9].…”

Section: Introductionmentioning

confidence: 99%

EXAFS studies on adsorption irreversibility of Zn(II) on TiO2: Temperature dependence

Pan

Zhang

et al. 2008

Journal of Colloid and Interface Science

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Adsorption irreversibility of Zn(II) on TiO 2 at various temperatures was studied using a combination of classical macroscopic methods and extended X-ray absorption fine structure (EXAFS) spectroscopy. When the temperature was increased from 5 to 40 • C, the Zn(II) adsorption capacity increased by 130%, and adsorbed Zn(II) became more reversible. The standard Gibbs free energy change ( G 0 ) of the adsorption reaction at 5, 20, and 40 • C was determined to be −19.58 ± 0.30, −22.28 ± 0.10, and −25.14 ± 0.21 kJ mol −1 , respectively. And the standard enthalpy ( H 0 ) and entropy ( S 0 ) were 24.55 ± 2.91 kJ mol −1 and 159.13 ± 0.53 J mol −1 K −1 , respectively. EXAFS spectra results showed that the hydrated Zn(II) was adsorbed through fourfold coordination with an average Zn-O bond distance of 1.98 ± 0.01 Å. Two Zn-Ti atomic distances of 3.25 ± 0.02 and 3.69 ± 0.03 Å were observed, which corresponded to an edge-sharing linkage mode (strong adsorption) and a cornersharing linkage mode (weak adsorption), respectively. As the temperature increased from 5 to 40 • C, the number of strong adsorption sites (N 1 ) remained relatively constant while the number for the weak adsorption sites (N 2 ) increased by 31%. These results indicate that the net gain in adsorption capacity and the decreased adsorption irreversibility at elevated temperatures were due to the increase in available weak adsorption sites (N 2 ) or the decrease in the ratio of N 1 /N 2 . Both the macroscopic sorption/desorption equilibrium data and the molecular level evidence of this study suggest that in a given environmental system (e.g., soils or natural waters) zinc and other similar heavy metals are likely more mobile at higher temperatures.

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“…However the equilibrium Zn concentrations (25-200 μg ml − 1 ) at which he studied Zn sorption were much higher than natural soil solution Zn concentrations. It has been shown that sorption/ desorption of Zn at natural soil solution concentrations is different from its sorption/desorption behaviour at higher concentrations (Hendrickson and Corey, 1981;Garcia-Miragaya et al, 1986). Even the mechanism of Zn sorption/desorption could differ between low and high Zn concentrations in soil (Elrashidi and O'Connor, 1982b).…”

Section: Introductionmentioning

confidence: 99%

Zinc sorption–desorption by soils: Effect of concentration and length of contact period

2006

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Surface loading effect on Cd and Zn sorption by kaolinite and montmorillonite from low concentration solutions

Cited by 26 publications

References 27 publications

Factors influencing metal bioavailability in soils: preliminary investigations for the development of a critical loads approach for metals

Factors influencing metal bioavailability in soils: preliminary investigations for the development of a critical loads approach for metals

EXAFS studies on adsorption irreversibility of Zn(II) on TiO2: Temperature dependence

Zinc sorption–desorption by soils: Effect of concentration and length of contact period

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