Carbonate adsorption onto goethite as a function of pH and ionic strength. [Yucca Mountain Project:a1]

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:6276957

Rundberg, R S ^[1]; Albinsson, Y ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Nuclear Chemistry

The adsorption of carbonate onto geothite was studied as a function of both pH and ionic strength (NaClO{sub 4} electrolyte) using {sup 14}C tracer. The pH ranged from 2.5 to 11.6. The ionic strength was controlled by varying the NaClO{sub 4} concentration and ranged from 0.01 to 0.1 molar. The results indicate that carbonate is adsorbed on goethite as primarily an inner-sphere complex at pH values above the point of zero charge. This is inferred from the lack of dependence on ionic strength in the adsorption of carbonate. Below the point of zero charge carbonate is adsorbed by an additional outer-sphere mechanism. An adsorption isotherm was measured at pH 7.0 with an electrolyte concentration of 0.01M. Deconvolution of the isotherm proved that at least two sorption mechanisms exist. These mechanisms lead to large distribution coefficients at low pH. Thereby making the complete removal and exclusion of carbonate from an aqueous goethite system difficult, for the purpose of characterizing a clean'' goethite surface.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6276957
• Report Number(s): LA-UR-91-3244; CONF-9110152--3; ON: DE92002362
• Country of Publication: United States
• Language: English

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BETA DECAY RADIOISOTOPES
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