Enter your fluid composition on the Basis pane. SpecE8 figures concentrations of aqueous and sorbed species, mineral saturation, and gas fugacity. Go to.

Slides:

Advertisements

Similar presentations

Lecture 20. Adsorption Phenomena

Advertisements

Oxidation and Reduction

Solution Definition and Speciation Calculations Ca Na SO4 Mg Fe Cl HCO3 Reaction calculations Saturation Indices Speciation calculation.

Nernst Equation Consider the half reaction:

ACTIVITY. Activity Coefficients No direct way to measure the effect of a single ion in solution (charge balance) Mean Ion Activity Coefficients – determined.

Model water-rock interaction Enter your initial fluid composition on the Basis pane, then go to the Reactants pane to create a reaction path. Titrate in.

Simulation lasts 30 years Aquifer is 70% Quartz Specify domain’s starting fluid composition on the Initial pane Initial fluid in equilibrium with Quartz.

Introduction to Electroanalytical Chemistry

K d, Freundlich, and Langmuir isotherms. File → New → Sorbing Surfaces → Kd Pull aqueous species from a thermo dataset Enter a unique identifier for the.

Picking up calculation results. After performing a calculation, React can “pick up” the results and use them for a new calculation. You can pick up an.

Introduction For remediation of soils and purification of polluted waters, wastewaters, biosorbents might be considered as prospective groups of materials.

Balancing Redox Reactions with Oxidation Numbers (see p 462) 1.Assign oxidation number 2.Identify oxidation and reduction 3.Determine the # of e- lost.

Conservative and Reactive Solutes Conservative do not react with soil / groundwater Chloride is a good example Sorbed onto mineral grains as well as organic.

IS SOLUBILITY THE ONLY CONTROL ON SOLUTE CONCENTRATIONS? The answer is NO! Solubility often controls the concentrations of major solutes such as Si, Ca,

Ion Exchange. File → New → Sorbing Surfaces → ion-exchange → Gaines-Thomas Aqueous species are drawn from a thermo dataset to create surface reactions.

Talal Almeelbi Surface Complexations of Phosphate Adsorption by Iron Oxide.

Act2 generates stability diagrams on activity, Eh, pe, pH, and fugacity axes. Select main species to diagram. Diagram axes.

Enter your initial fluid composition on the Basis pane, then go to the Reactants pane to create a reaction path. Choose the type of kinetic reaction.

From GWB apps, File → View → …\thermo.tdat From TEdit, File → Open → Thermo Data… → …\thermo.tdat From Windows explorer, double-click the file You can.

Clean water Start and end times of two reaction intervals Specify domain’s starting fluid composition on the Initial pane.

Ankan Basu Geologist Marshall Miller and Associates Bluefield, VA, Date: April 22, 2009 Geochemical Modeling with Geochemist’s Workbench.

USING FREE GEOCHEMICAL SOFTWARE FROM THE U.S. GEOLOGICAL SURVEY DEVIN CASTENDYK STATE UNIVERSITY OF NEW YORK, ONEONTA

Minerals and water ーPHREEQC programsー

Viewing thermo datasets in TEdit. From GWB apps, File → View → …\thermo.tdat From TEdit, File → Open → Thermo Data… → …\thermo.tdat From Windows explorer,

CHARACTERIZATION OF SORPTION AND QUANTITATIVE ANALYSIS OF HYDROXYL COMPLEXES CHARACTERIZATION OF SORPTION AND QUANTITATIVE ANALYSIS OF HYDROXYL COMPLEXES.

Decouple reaction between carbonate and Benzene(aq), other forms of carbon. Config → Redox Couples… Default setting: all redox reactions are coupled.

GSS is a spreadsheet for manipulating and plotting geochemical data. Right-click to convert units.

Run → Go draws the diagram Add any background ions Set temperature Select main species to diagram Choose axes Act2 generates stability diagrams on activity,

Right-click on unit field to convert units GSS is a spreadsheet for manipulating and plotting geochemical data.

Redox Reactions – Examples(1 – Synthesis) The following is one type of oxidation/ reduction reaction. 1.Balance the equation. 2.Indicate the species that.

Balance chemical reactions. Start by choosing a species to appear on the left side of the reaction. Move to the Results pane. Rxn writes a reaction with.

What do you call a rusty cow? A Redox!. Balancing Redox Equations In Acidic & Basic Solution.

Concentrations vs. Activities Activities ≠ concentrations Activities ≠ concentrations Activities are “effective” concentrations Activities are “effective”

Act2 and Tact Calculate stability diagrams on activity, fugacity, and temperature axes. Calculate solubility diagrams. Project traces of React runs onto.

Substrate combines with enzyme to form activated complex, which can decay to give catalytic product Michaelis-Menten equation gives rate of forward reaction.

React Conceptual Model Equilibrium in Multicomponent Systems The “basis” Secondary species Mass action Mass balance.

Kinetic reactions React, X1t, and X2t can trace several types of reactions according to kinetic rate laws: Mineral precipitation and dissolution. Redox.

Challenges with simultaneous equilibrium Speciation programs (MINEQL)

Config→ Redox couples… Decouple redox pairs for electron donating and accepting half reactions.

Decouple reaction between carbonate and acetate, carbonate and methane, and sulfate and sulfide. Config → Redox Couples… Default setting: all redox reactions.

Set the initial fluid composition on the Basis pane. Dilute fluid, pH 5 Click to add components to the fluid.

Specify kinetic rate laws for mineral precipitation and dissolution (and other reaction types) on the Reactants pane. Use Arrhenius equation to calculate.

Enter your fluid composition on the Basis pane

File → Open → Thermo Data…

Config → Redox Couples…

Config→ Redox couples…

Set the simulation’s duration

GSS is a spreadsheet for manipulating and plotting geochemical data.

Specify domain’s starting fluid composition on the Initial pane

Specify domain’s starting fluid composition on the Initial pane

Set the initial fluid composition on the Basis pane.

Specify domain’s starting fluid composition on the Initial pane

Equilibrium equations

Set the composition of the initial fluid on the Basis pane.

Specify domain’s starting fluid composition on the Initial pane

Two-layer datasets.

Default setting: all redox reactions are coupled.

Concentrations and activities

React traces reaction paths involving fluids, minerals, gases, and microbes.

pH Saturation, some minerals (Q/K) , Ÿ œ + › Amrph^ silica Chalcedony

Config → Redox couples… Decouple redox pairs for electron donating and accepting half reactions.

log a U pH °C Uraninite U UOH U(OH) –16 –14

Config → Redox couples… Decouple redox pairs for electron donating and accepting half reactions.

Add and delete entries.

Disable redox coupling between As(V) and As(III), Fe(III) and Fe(II)

Choose the type of kinetic reaction

Comparison of Linear and Non-linear Methods on Sorption Isotherm

A Deeper Insight into the Meaning of k° and α.

Swap sorbing mineral into the basis

Config→ Redox couples…

Presentation transcript:

Enter your fluid composition on the Basis pane. SpecE8 figures concentrations of aqueous and sorbed species, mineral saturation, and gas fugacity. Go to the Results pane, click Run, then view printed or plotted results

Concentrations and activity coefficients for all aqueous species are printed.

Add species to the Basis pane. Decouple any redox species for which analyses in multiple oxidation states are available. Decouple Fe 3+ from Fe 2+ and As(OH) 4 − from AsO 4 3− Config → Redox couples...

First value listed is system Eh Redox state for As(OH) 4 − /AsO 4 3− and Fe 3+ /Fe 2+ pairs are computed using Nernst equation. Widely varying Eh values indicate system has not reached redox equilibrium.

Calculated mineral saturation states and gas fugacities are listed in the output file. Calculated mineral saturation states Calculated gas fugacities

Plot → Piper Diagram A Piper Diagram shows the fluid's major ion composition.

File → Open → Thermo Data... Select thermo_hmw.dat to calculate activity using the Pitzer equations.

File → Open → Sorbing Surfaces... Open dataset of sorption reactions. Options include distribution coefficient (Kd), Freundlich and Langmuir isotherms, ion exchange, and Double Layer surface complexation models. Enter your fluid composition on the Basis pane, including the mass of sorbing mineral Fe(OH)3(ppd).

View calculated surface charge and potential of sorbing minerals. Compare concentrations of sorbed and aqueous species. View calculated distribution between surface and solution. Concentrations of all surface complexes are listed along with Boltzman factors which show the magnitude of electrostatic corrections.