The amount of calcite dissolved for each mixture of fresh and saline groundwater to reach equilibrium was calculated with the PHREEQC code (Parkhurst, 1995), resulting the curve A in Fig. 3. The procedure can be formalized as follows. First, solving the transport equation for dissolved calcite ceq K ckC1 Dt (4) Three points should be noticed.
Abstract. The adsorption, partitioning, and diffusion of CO 2 and CH 4 in organic–inorganic pores composed of kerogen with silica, illite, or calcite are studied using density functional theory and classical molecular dynamics simulations. The adsorption and partitioning behavior of CO 2 and CH 4 molecules is found to be a function of chemistry …
We conducted experiments in which the reaction of single calcite crystals with a Mg-rich fluid at 200 °C leads to the formation of a zoned reaction rim consisting of magnesite …
The reactive transport of biochemical species in the soil mass initiates the precipitation of biocement during the MICP process. The precipitated biocement alters the hydro-mechanical performance of the soil mass. ... (De Muynck et al., 2010; Lai et al ... The calcite distribution was observed to match reasonably well in the verification and ...
To enhance mass transport one usually stirs the solution, surrounding the calcite surfaces, by an impeller, thus creating some kind of turbulent flow, where mass transport into the …
The reaction of GLDA with calcite was investigated by measuring the rate of dissolution using the rotating disk apparatus. The effect of initial pH (1.7, 3.8, and 13) and disk rotational speed ...
The consideration of water mass reacting to precipitate calcite. A model of bacterial transport, with a limit on the bacteria concentration that can be attached. ... Biver P (1993) Etude phenomenologique et numerique de la propagation de polluants miscibles dans un milieu a porosite multiple: Application au transport des nitrates dans l ...
This study indicates that reactive transport modeling of calcite deposition can yield important constraints on the unsaturated zone infiltration-percolation flux and provide useful insight into processes such as fracture–matrix interaction as well as …
This study indicates that reactive transport modeling of calcite deposition can yield important constraints on the unsaturated zone infiltration-percolation flux and provide …
The purpose of this study was to investigate the relationship between percolation flux and measured calcite abundances using reactive transport modeling. Our model considers the following essential factors affecting calcite precipitation: (1) infiltration, (2) the ambient geothermal gradient, (3) gaseous CO(2) diffusive transport and ...
Microbially induced calcite precipitation (MICP) offers an alternative solution to a wide range of civil engineering problems. Laboratory tests have shown that MICP can immobilize trace metals and radionuclides through co-precipitation with calcium carbonate. MICP has also been shown to improve the undrained shear response of soils …
Molecular dynamics (MD) simulations at several different temperatures were run to investigate the transport, adsorption, and stability of carbon dioxide (CO2) and water phases in contact with a calcite surface. All simulated systems showed evidence of CO2 transport and interface stability heavily affected by the presence of calcite and the …
Calcite {1 0 1-4} and {0 0 0 1} surfaces are selected in this work as representative mineral surfaces of nano-pore walls with neutral and charged characteristics. The effects of surface charge in altering the wettability of calcite mineral surfaces, in the presence of different salt concentrations, are investigated using classical, equilibrium ...
The biogeochemical process known as microbially induced calcite precipitation (MICP) is being investigated for engineering and material science applications. To model MICP process behavior in porous media, computational simulators must couple flow, transport, and relevant biogeochemical reactions. Changes in media …
Although faster than typical calcite values of 0.5–4 nm/s (Lea et al., 2001, De Giudici, 2002, Arvidson et al., 2006, Harstad and Stipp, 2007, Ruiz-Agudo et al., 2009), they are in the range for observations at the edges of coalescing etch pits of 7.9–14.3 nm/s (Vinson and Luttge, 2005). Etch pit coalescence is expected when the calcite ...
Calcite content, Sr concentrations, and isotopes of calcites in the Chinese deserts are systematically studied in this paper. ... Long-distance dust transport towards the NPO was achieved mainly by the upper-level westerly winds and regional dust transport in China was accomplished by low-level northwesterly winds (Merrill et al., …
We injected two calcite systems with HCl acid and performed corresponding simulations to understand the chemical and transport mechanisms during the dissolution process. The first experiment consisted of channel drilled through a solid calcite core and provided a simple flow system with which to compare overall mass dissolution rates …
The inlet fluid used in the experiments was a 50–50% mixture of CaCl 2 and NaHCO 3 solutions prepared from reagent-grade salts dissolved in deionized water and equilibrated with atmospheric P CO2.The composition of the mixture is 1.87 ± 0.03 mM CaCl 2 and 3.95 ± 0.07 mM NaHCO 3 and corresponds to a calcite saturation index (log …
GLDA transport and its effect on wormhole creation were investigated in core flood experiments using samples of 1.5 in. diameter and 6 in. length. The cores were scanned using CT-scan before and after the injection of GLDA solutions into the cores. ... The calcite dissolution rate was found to be a strong function of temperature and …
Reaction rates involving growth or dissolution of calcite can be either transport- or surface-controlled (Morse, 1983; Lasaga, 1998). This distinction potentially has important ramifications for the Mg contents of natural calcite samples, especially where biomineralization in different organisms is concerned.
In this study, the oil–water two-phase occurrence state and fluid transport in shale inorganic calcite nanopores are investigated utilizing molecular dynamics simulation. The multilayer sticking ...
The temperature dependence of the overall transport rate of MgCO3 into calcite can be described by the kinetic parameters (E = 231.7 kJ/mol and A o = 22.69 h−1). Extrapolation using the Arrhenius equation to the conditions during exhumation of UHPM rocks indicates that the reaction of dolomite with aragonite into Mg-saturated calcite can be ...
Geochemistry and reactive transport play a critical role in many fields. In particular, calcite dissolution and precipitation are chemical processes occurring ubiquitously in the Earth's subsurface.
Geochemistry and reactive transport play a critical role in many fields. In particular, calcite dissolution and precipitation are chemical processes occurring ubiquitously in the Earth's subsurface. Therefore, understanding and quantifying them are necessary for various applications (e.g., water resources, reservoirs, geo-engineering). …
Semantic Scholar extracted view of "Bio-geochemical reactive transport modeling of microbial induced calcite precipitation to predict the treatment of sand in one-dimensional flow" by B. C. Martinez et al.
The adsorption, partitioning, and diffusion of CO2 and CH4 in organic–inorganic pores composed of kerogen with silica, illite, or calcite are studied using density functional theory and classical molecular dynamics simulations. The adsorption and partitioning behavior of CO2 and CH4 molecules is found to be a function of chemistry of …
DOI: 10.1016/J.JHYDROL.2004.12.017 Corpus ID: 140653656; Reactive transport modeling of calcite dissolution in the fresh-salt water mixing zone @article{Rezaei2005ReactiveTM, title={Reactive transport modeling of calcite dissolution in the fresh-salt water mixing zone}, author={Mohsen Rezaei and Esteban Sanz and …
Calcite Production. The major steps for Calcite production are as mentioned below: Step 1: Crush the incoming minerals and transfer them to ball mills to convert them to powder form. Step 2: Sieve the powder form and separate it into the desired grades.. Step 3: Split the powder in 3-micron, 5-micron, 10- micron bags as required.. The …
Using mol. dynamics simulations, we show that CO2 adsorption on calcite surfaces impedes decane transport at moderate adsorption d. but enhances decane transport when CO2 adsorption approaches surface satn. These effects change the decane permeability through 8 nm-wide pores by up to 30% and become negligible only …
@article{osti_877665, title = {A Reaction-Transport Model for Calcite Precipitation andEvaluation of Infiltration Fluxes in unsaturated fractured rock}, author = {Xu, Tianfu and Sonnenthal, Eric and Bodvarsson, Gudmundur}, abstractNote = {The percolation flux in the unsaturated zone (UZ) is an important parameter addressed in site …
In our formulation we assumed: the transport is advective-dispersive with nonuniform flow due to hydraulic boundaries (the porous medium is homogeneous) and with Fickian dispersion with constant …
Geochemical reactive transport processes in natural mineral–fluid systems may produce a wide array of emergent phenomena that are difficult to predict from basic principles and …
The structure and transport of the heavy asphaltene molecules in unconfined bulk fluids and fluids confined in a 4 nm slit-shaped nanopores of calcite and silica were studied using classical molecular dynamics simulations. The pores were filled with 7 wt% of asphaltene dissolved in an equimolar solvent of heptane and toluene.
Abstract. Molecular dynamics (MD) simulations at several different temperatures were run to investigate the transport, adsorption, and stability of carbon dioxide (CO 2) and water phases in contact with a calcite surface. All simulated systems showed evidence of CO 2 transport and interface stability heavily affected by the …