Can we replace Hfo : Hydrous Ferrous oxide surface with other mineral surface.?

[snjaykdubey]

Dear Sir,
I have following doubt related to surface complexation:
Problem: Can we replace the keyword Hfo(Hydrous Ferric Oxide ) to desired name like SW_sOH since i would like to study the surface complexation behavior for X element on Montmorillonite not on Hydrous Ferric oxide.(I can get the log K value for strong and weak site from Database. ).
I try to did above calculation still i got error. But i dont understand.
Hope you can help me to understand the main concept.

Database :Llnl used

Following Error :
ERROR: Element or valence name in SOLUTION_MASTER_SPECIES should include only one element, SW_psi.
ERROR: Element or valence name in SOLUTION_MASTER_SPECIES should include only one element, SW_psib.
ERROR: Element or valence name in SOLUTION_MASTER_SPECIES should include only one element, SW_psid.
ERROR: Element or valence name in SOLUTION_MASTER_SPECIES should include only one element, SW_s.
ERROR: Element or valence name in SOLUTION_MASTER_SPECIES should include only one element, SW_w.
ERROR: Element or valence name in SOLUTION_MASTER_SPECIES should include only one element, SW_ww.
ERROR: No master species for element W_psi.
ERROR: Could not find primary master species for W_psi.
ERROR: No master species for element W_psi.
ERROR: No master species for element W_psib.
ERROR: Could not find primary master species for W_psib.
ERROR: No master species for element W_psib.
ERROR: No master species for element W_psid.
ERROR: Could not find primary master species for W_psid.
ERROR: No master species for element W_psid.
ERROR: No master species for element W_s.
ERROR: Could not find primary master species for W_s.
ERROR: No master species for element W_s.
ERROR: No master species for element W_w.
ERROR: Could not find primary master species for W_w.
ERROR: No master species for element W_w.
ERROR: No master species for element W_ww.
ERROR: Could not find primary master species for W_ww.
ERROR: No master species for element W_ww.
ERROR: Master species not in data base for W_s, skipping element.
ERROR: Master species not in data base for W_w, skipping element.
ERROR: Master species not in data base for W_ww, skipping element.
ERROR: No surface master species for surface component SW_sOH,
ERROR: No surface master species for surface component SW_wOH,
ERROR: No surface master species for surface component SW_wwOH,
ERROR: Calculations terminating due to input errors.
Stopping.


I don't understand the error...

Awaiting for your reply,
Regards,
Sanjay

[weird]

I have the same question as you ,I what to simulate the reaction as below: SiOH+Zn2+=SiOZn+ + H+，I don't know how to difine the new reaction which can not be found in the datebase and how to get the Log_K of the reaction.

[snjaykdubey]

Hey weird

I think for K value u have to look in the database or literature
for strong and weak site .


there is one research paper
i hope it will help u.. But i am not sure. please go through it.
it calculate log k value for Zn sorption on montmorillonite
they have log k value for strong and weak site.

http://www.sciencedirect.com/science/article/pii/S0016703711003632

In order to get log k for any element on surface of mineral u can use following site
.it good one
 http://www.hzdr.de/db/RES3T.queryData


regards,
Sanjay

[dlparkhurst]

You can add surface complexation for other surfaces. You will need to mimic the SURFACE_MASTER_SPECIES and SURFACE_SPECIES definitions (not SOLUTION_MASTER_SPECIES and SOLUTION_SPECIES) for Hfo in phreeqc.dat.

SURFACE_MASTER_SPECIES
   Hfo_s           Hfo_sOH
   Hfo_w       Hfo_wOH

For each surface site, you need one reaction for the master species defined in SURFACE_MASTER_SPECIES. Possibly reactions for protonation and deprotonation reactions, and reactions for each surface complexation species, here just Ca+2.

SURFACE_SPECIES
# All surface data from
# Dzombak and Morel, 1990
#
#
# Acid-base data from table 5.7
#
# strong binding site--Hfo_s,

   Hfo_sOH = Hfo_sOH
   -log_k   0

   Hfo_sOH   + H+ = Hfo_sOH2+
   -log_k   7.29   # = pKa1,int

   Hfo_sOH = Hfo_sO- + H+
   -log_k   -8.93   # = -pKa2,int

# weak binding site--Hfo_w

   Hfo_wOH = Hfo_wOH
   -log_k   0

   Hfo_wOH   + H+ = Hfo_wOH2+
   -log_k   7.29   # = pKa1,int

   Hfo_wOH = Hfo_wO- + H+
   -log_k   -8.93   # = -pKa2,int

   Hfo_sOH + Ca+2 = Hfo_sOHCa+2
   -log_k   4.97


Note that capital letters in chemical formulas denote the beginning of an element name. Thus, SW_w is interpreted as one mole of S (sulfur) and one mole of W_w (W weak sites). Something like Mont_w would work for montmorillonite.

[snjaykdubey]

Thanks Sir,
With above modification program is running

[chevron]

Hello, I have a few questions that I hope you can help me out with.

How can I denote Goethite with the llnl and phreeqc data sets?  I gave a few variations a shot, but all ended up in errors.  I am currently using HFO, and would like to compare the two. 

Also, I had a few questions about your previously posted example:

SURFACE_MASTER_SPECIES
   Hfo_s           Hfo_sOH
   Hfo_w       Hfo_wOH

***I dont quite understand why you have this section.  Are you just defining the notation of the strong and weak adsorption sites?  If so, why do you write them with and without an OH?  Shouldn't Hfo_sOH2+ and Hfo_sO- also be included? 

SURFACE_SPECIES
   Hfo_sOH = Hfo_sOH
   -log_k   0

   Hfo_sOH   + H+ = Hfo_sOH2+
   -log_k   7.29   # = pKa1,int

   Hfo_sOH = Hfo_sO- + H+
   -log_k   -8.93   # = -pKa2,int

***Why do you write surface acidity constants for the Hfo strong sites when there is no reaction defined for strong site adsorption?  Is this just book keeping, or is it necessary for proper execution?

Thanks for your help/guidance.   

[dlparkhurst]

SURFACE_MASTER_SPECIES is used to define all of the types of sites, first item on each line, and the master species for each type of site, second item.

SURFACE_MASTER_SPECIES
   Hfo_s           Hfo_sOH
   Hfo_w       Hfo_wOH

Thus Hfo_s and Hfo_w are types of sites, and Hfo_sOH and Hfo_wOH are actual surface species and are called "master" species. There is only one master species for each site type. For any surface species involving Hfo_s, say Hfo_sOH2+, PHREEQC needs to be able to derive an equation that creates that species from Hfo_sOH and other aqueous master species. Usually, the defined equation is already in that form:

Hfo_sOH + H+ = Hfo_sOH2+

This equation makes the non master species (Hfo_sOH2+) from the master species Hfo_sOH. There is one equation that creates each surface species in SURFACE_SPECIES. You can write equations that do not directly involve the master species, but it must be possible to add equations so that an equation like the one above can be derived. If it is not done correctly, you will get error messages.


The definitions for Hfo_s and Hfo_w in phreeqc.dat have appropriate definitions and serve as an example. You need one master surface species for each site type (SURFACE_MASTER_SPECIES), and in SURFACE_SPECIES, you need an identity equation for each surface master species, and an equation for every other surface species.

[chevron]

Dlparkhurst, thank you very much for your help. 

Regarding my question about simulating adsorption on Goethite: Do I just write Hfo as a master species but define constants for acidity/adsorption/surface area/reactive sites for Goethite as opposed to amorphous ferric hydroxide? 

Or is there specific notation for Goethite that needs to be used in with this software?

Thanks again

[dlparkhurst]

You can use whatever names you want for the surface type, provided it is unique, begins with a capital letter, and has zero or more lower case letters following. "Goe" is acceptable for a single site surface, or Goe_w and Goe_s for a surface with weak and strong sites.