[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

diolution of Air composition

Mr. Parkhurst:

Hi, how are you !

I am very appreciated of your help on my question last time . I don't know
if you had time to think over the question on caron dioxide. I remembered
that you said you were out of town for two weeks. I sent a email to you then
and i am not sure if you got it.

So I here sum it up in this way:

I am trying to simulate the disolution of the gas composition of air in
solution which is bubbled with a humidified air in lab experimental
condition. The concentration of carbonate is unknown.

I tried to set the initial data in

		-pressure 		1.0
      	-temperature    25.0
		CO2(g)          0.000316
		O2(g)           0.2
		N2(g)           0.78

as well as

        Fix_H+   -8.0   NaOH    10.0
	CO2(g)	-3.5
	O2(g)       -0.69897
	N2(g)       -0.1079

The pH are set as fixed from 2-10.

There are 1 mg/l U in the soultion and adsortion by iron oxide are allowed

The first one comes out with the carbonate distribution as shown in attached
file while the second one doesn't converge. I tried the KNOBS data but
didn't work. Butwhen I took away the O2(g) and N2(g) from the data set, it
gave a fairly good result.

Here is my questions:

1. which one data set should i use to represent the experimental condition ?

2. I used the Fixed_H+ for constant pH. In order to keep the acid-base and
calculation balance, I need to assumed some acid or base present as Manual
recommended. Don't  they influence the chemical reaction, such as to
increase or decrease the dissolution of CO2 ? how to avoid using the assumed
acid or base ? Any advices if necessary?

Thanks a lot for your precious time and help.

Yours sincerely,

Young Wang
Department of Geology

Attachment: question.doc
Description: MS-Word document

Project Home Page
Complete Water Resources Division Software
USGS Home Page
Water Resources Division Home Page
NRP Home Page
Help Page
USGS Privacy Statement       

Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. 

The URL of this page is: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/mail/msg00034.html
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 2924 since Jan 22, 1998.