Dissolution kinetics of a lunar glass simulant at 25 degrees C : the effect of pH and organic acids

The dissolution kinetics of a simulated lunar glass were examined at pH 3, 5, and 7. Additionally, the pH 7 experiments were conducted in the presence of citric and oxalic acid at concentrations of 2 and 20 mM. The organic acids were buffered at pH 7 to examine the effect of each molecule in their...

Ausführliche Beschreibung

Bibliographische Detailangaben
Veröffentlicht in:Geochimica et cosmochimica acta. - 1984. - 60(1996), 1 vom: 26. Jan., Seite 157-70
1. Verfasser: Eick, M J (VerfasserIn)
Weitere Verfasser: Grossl, P R (BerichterstatterIn), Golden, D C, Sparks, D L, Ming, D W
Format: Aufsatz
Sprache:English
Veröffentlicht: 1996
Zugriff auf das übergeordnete Werk:Geochimica et cosmochimica acta
Schlagworte:Journal Article Research Support, U.S. Gov't, Non-P.H.S. NASA Center JSC NASA Discipline Life Support Systems Minerals Oxalates Soil Citric Acid 2968PHW8QP Oxalic Acid mehr... 9E7R5L6H31 Aluminum CPD4NFA903 Titanium D1JT611TNE Silicon Z4152N8IUI
LEADER 01000caa a22002652 4500
001 NLM114392021
003 DE-627
005 20250202194840.0
007 tu
008 231222s1996 xx ||||| 00| ||eng c
028 5 2 |a pubmed25n0382.xml 
035 |a (DE-627)NLM114392021 
035 |a (NLM)11541298 
040 |a DE-627  |b ger  |c DE-627  |e rakwb 
041 |a eng 
100 1 |a Eick, M J  |e verfasserin  |4 aut 
245 1 0 |a Dissolution kinetics of a lunar glass simulant at 25 degrees C  |b the effect of pH and organic acids 
264 1 |c 1996 
336 |a Text  |b txt  |2 rdacontent 
337 |a ohne Hilfsmittel zu benutzen  |b n  |2 rdamedia 
338 |a Band  |b nc  |2 rdacarrier 
500 |a Date Completed 15.07.1997 
500 |a Date Revised 05.11.2019 
500 |a published: Print 
500 |a Citation Status MEDLINE 
520 |a The dissolution kinetics of a simulated lunar glass were examined at pH 3, 5, and 7. Additionally, the pH 7 experiments were conducted in the presence of citric and oxalic acid at concentrations of 2 and 20 mM. The organic acids were buffered at pH 7 to examine the effect of each molecule in their dissociated form. At pH 3, 5, and 7, the dissolution of the synthetic lunar glass was observed to proceed via a two-stage process. The first stage involved the parabolic release of Ca, Mg, Al, and Fe, and the linear release of Si. Dissolution was incongruent, creating a leached layer rich in Si and Ti which was verified by transmission electron microscopy (TEM). During the second stage the release of Ca, Mg, Al, and Fe was linear. A coupled diffusion/surface dissolution model was proposed for dissolution of the simulated lunar glass at pH 3, 5, and 7. During the first stage the initial release of mobile cations (i.e., Ca, Mg, Al, Fe) was limited by diffusion through the surface leached layer of the glass (parabolic release), while Si release was controlled by the hydrolysis of the Si-O-Al bonds at the glass surface (linear release). As dissolution continued, the mobile cations diffused from greater depths within the glass surface. A steady-state was then reached where the diffusion rate across the increased path lengths equalled the Si release rate from the surface. In the presence of the organic acids, the dissolution of the synthetic lunar glass proceeded by a one stage process. The release of Ca, Mg, Al, and Fe followed a parabolic relationship, while the release of Si was linear. The relative reactivity of the organic acids used in the experiments was citrate > oxalate. A thinner leached layer rich in Si/Ti, as compared to the pH experiments, was observed using TEM. Rate data suggest that the chemisorption of the organic anion to the surface silanol groups was responsible for enhanced dissolution in the presence of the organic acids. It is proposed that the increased rate of Si release is responsible for the one stage parabolic release of mobile cations and the relatively thin leached layer compared to experiments at pH 3 and 5 
650 4 |a Journal Article 
650 4 |a Research Support, U.S. Gov't, Non-P.H.S. 
650 4 |a NASA Center JSC 
650 4 |a NASA Discipline Life Support Systems 
650 7 |a Minerals  |2 NLM 
650 7 |a Oxalates  |2 NLM 
650 7 |a Soil  |2 NLM 
650 7 |a Citric Acid  |2 NLM 
650 7 |a 2968PHW8QP  |2 NLM 
650 7 |a Oxalic Acid  |2 NLM 
650 7 |a 9E7R5L6H31  |2 NLM 
650 7 |a Aluminum  |2 NLM 
650 7 |a CPD4NFA903  |2 NLM 
650 7 |a Titanium  |2 NLM 
650 7 |a D1JT611TNE  |2 NLM 
650 7 |a Silicon  |2 NLM 
650 7 |a Z4152N8IUI  |2 NLM 
700 1 |a Grossl, P R  |e verfasserin  |4 aut 
700 1 |a Golden, D C  |e verfasserin  |4 aut 
700 1 |a Sparks, D L  |e verfasserin  |4 aut 
700 1 |a Ming, D W  |e verfasserin  |4 aut 
700 1 |a Ming, D W  |e investigator  |4 oth 
773 0 8 |i Enthalten in  |t Geochimica et cosmochimica acta  |d 1984  |g 60(1996), 1 vom: 26. Jan., Seite 157-70  |w (DE-627)NLM098120409  |x 0016-7037  |7 nnns 
773 1 8 |g volume:60  |g year:1996  |g number:1  |g day:26  |g month:01  |g pages:157-70 
912 |a GBV_USEFLAG_A 
912 |a SYSFLAG_A 
912 |a GBV_NLM 
912 |a GBV_ILN_350 
951 |a AR 
952 |d 60  |j 1996  |e 1  |b 26  |c 01  |h 157-70