Physics
Scientific paper
Oct 1985
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1985gecoa..49.2165i&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 49, Issue 10, pp.2165-2180
Physics
10
Scientific paper
We used a reproducible seeded growth technique with a pH-stat to study the kinetics of calcite precipitation at 25°C. We performed different experiments at initial Ca 2+ and HCO 3 - concentrations ranging from 0.7-2 and 4-7 mmol L -1 , pH values ranging from 8.25 to 8.70, pCO 2 values ranging from 0.0006 to 0.01 atm, and ionic strengths ranging from 0.015 to 0.10 mol L -1 . With this experimental data set, we used initial rate measurements and integral methods to test several precipitation rate equations. Rate equations that possess a disequilibrium functional dependence, such as the BURTON et al . (1951) dislocation model, forms of the Davies and Jones (1955) model, and the model used by and (1973), did not adequately describe the kinetics of calcite precipitation at pH greater than 8 and pCO 2 less than 0.01 atm. Rate equations that describe independent dissolution and precipitation mechanisms with elementary reactions, such as the equation presented by et al . (1978), and and (1971) were more successful. However, Plummer's model did not adequately describe the rate of all experiments due to the presence of an OH - surface term in the precipitation rate equation. The elementary reaction of the and model is written in terms of bulk Ca 2+ and CO 3 - concentrations, and appears to be the most successful model which describes calcite precipitation at pH > 8 and pCO 2 < 0.01 atm. The and model, altered to account for varying ionic strengths, adequately described the rate of all experiments and yielded a precipitation rate constant of 118.2 ± 13.9 dm 6 mol -1 m -2 s -1 , with an apparent Arrhenius activation energy of 48.1 kJ mol -1 .
Bloom Paul R.
Inskeep William P.
No associations
LandOfFree
An evaluation of rate equations for calcite precipitation kinetics at pCO 2 less than 0.01 atm and pH greater than 8 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with An evaluation of rate equations for calcite precipitation kinetics at pCO 2 less than 0.01 atm and pH greater than 8, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An evaluation of rate equations for calcite precipitation kinetics at pCO 2 less than 0.01 atm and pH greater than 8 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1546167