Thermodynamics, interfacial structure, and pH hysteresis of Rb+ and Sr2+ adsorption at the muscovite (001)-solution interface

The coverage and average height of adsorbed Rb+ and Sr2+ at the muscovite (001)-solution interface were measured with resonant anomalous X-ray reflectivity (RAXR) as a function of cation concentration (10-8 < [Sr2+] < 10(-1) m, 10-6 < [Rb+] < 10(-1) m at pH 5.5 and 3.5) and pH (1.5 to 5....

Description complète

Détails bibliographiques
Publié dans:Langmuir : the ACS journal of surfaces and colloids. - 1985. - 24(2008), 24 vom: 16. Dez., Seite 13993-4004
Auteur principal: Park, Changyong (Auteur)
Autres auteurs: Fenter, Paul A, Sturchio, Neil C, Nagy, Kathryn L
Format: Article en ligne
Langue:English
Publié: 2008
Accès à la collection:Langmuir : the ACS journal of surfaces and colloids
Sujets:Journal Article
LEADER 01000caa a22002652c 4500
001 NLM184908345
003 DE-627
005 20250209235708.0
007 cr uuu---uuuuu
008 231223s2008 xx |||||o 00| ||eng c
024 7 |a 10.1021/la802446m  |2 doi 
028 5 2 |a pubmed25n0616.xml 
035 |a (DE-627)NLM184908345 
035 |a (NLM)19053665 
040 |a DE-627  |b ger  |c DE-627  |e rakwb 
041 |a eng 
100 1 |a Park, Changyong  |e verfasserin  |4 aut 
245 1 0 |a Thermodynamics, interfacial structure, and pH hysteresis of Rb+ and Sr2+ adsorption at the muscovite (001)-solution interface 
264 1 |c 2008 
336 |a Text  |b txt  |2 rdacontent 
337 |a ƒaComputermedien  |b c  |2 rdamedia 
338 |a ƒa Online-Ressource  |b cr  |2 rdacarrier 
500 |a Date Completed 01.05.2009 
500 |a Date Revised 10.04.2009 
500 |a published: Print 
500 |a Citation Status PubMed-not-MEDLINE 
520 |a The coverage and average height of adsorbed Rb+ and Sr2+ at the muscovite (001)-solution interface were measured with resonant anomalous X-ray reflectivity (RAXR) as a function of cation concentration (10-8 < [Sr2+] < 10(-1) m, 10-6 < [Rb+] < 10(-1) m at pH 5.5 and 3.5) and pH (1.5 to 5.5 at [Me(n+)] = 10(-3) m) without background electrolyte. At pH 5.5, Rb+ uptake approximately follows a Langmuir isotherm with deltaG(Rb)(o) = -23.5 +/- 4.0 kJ x mol(-1) and a saturation coverage of Tmax = 0.94 +/- 0.06 Rb+ per unit cell area, Auc = 46.72 A2, compensating the nominal surface charge density (1 e-/Auc). The Sr2+ isotherm has a saturation coverage of 0.47 +/- 0.05 Sr2+/Auc that also compensates the muscovite's charge, but the adsorption edge is both more abrupt and shifted significantly to lower concentration than that for Rb+. The uptake of Sr2+ is consistent with a Frumkin isotherm with an intrinsic adsorption constant, deltaG(Sr)(o) = -28.8 +/- 6.0 kJ x mol(-1) and a correlation energy, gamma(Sr) = -7.2 +/- 3.7 kJ x mol(-1). The average height of each adsorbed cation, corresponding to inner-sphere dominant Rb+ and coexisting inner- and outer-sphere Sr2+ distributions, was independent of ion coverage at pH 5.5. At pH 3.5, the adsorption edges of both ions shift to higher cation concentration, indicating competition with hydronium, and the shifts are accompanied by an irreversible reduction in the saturation coverage. The inner-sphere dominant mode of Rb+ adsorption did not change at pH 3.5, while that of Sr2+ changed to an outer-sphere dominant distribution. Hysteresis in both the amount and height of the adsorbed ion was observed as a function of the direction in which pH was changed, indicating that the intrinsic surface charge density decreased after reaction with acidic solutions. These results suggest new and unexpected interrelationships among the distribution of adsorbed ions, competitive adsorption of hydronium, and surface charge density at the mineral-solution interface 
650 4 |a Journal Article 
700 1 |a Fenter, Paul A  |e verfasserin  |4 aut 
700 1 |a Sturchio, Neil C  |e verfasserin  |4 aut 
700 1 |a Nagy, Kathryn L  |e verfasserin  |4 aut 
773 0 8 |i Enthalten in  |t Langmuir : the ACS journal of surfaces and colloids  |d 1985  |g 24(2008), 24 vom: 16. Dez., Seite 13993-4004  |w (DE-627)NLM098181009  |x 1520-5827  |7 nnas 
773 1 8 |g volume:24  |g year:2008  |g number:24  |g day:16  |g month:12  |g pages:13993-4004 
856 4 0 |u http://dx.doi.org/10.1021/la802446m  |3 Volltext 
912 |a GBV_USEFLAG_A 
912 |a SYSFLAG_A 
912 |a GBV_NLM 
912 |a GBV_ILN_22 
912 |a GBV_ILN_350 
912 |a GBV_ILN_721 
951 |a AR 
952 |d 24  |j 2008  |e 24  |b 16  |c 12  |h 13993-4004