9 replies to this topic

[Albertox]

Hello, i am working on my desalination plant proyect and i am having problems on calculate the pH of the fresh water right after the RO module.

 

I have tried with some Programs like Rosa FilmTec but everyone force me to use a membrane with the characteristics. I would like to know if there is a program where i can select the salt reject i want or if there is a program where i can select the concentration of the anions and cations and tell me the pH.

 

Thanks you very much

[thorium90]

If you just want to calculate the pH due to ions for a specific chemical...

 

http://www.endmemo.com/chem/phcal.php

 

If you just mean the pH from the H+ concentration...

 

http://academic.broo...page/ph_def.htm

 

Although, fyi,  the projection softwares calculate the pH of the water, reject and permeate automatically... Its already inside ROSA...

 

If you mean something else... do clarify...

Edited by thorium90, 09 January 2019 - 06:27 AM.

[Albertox]

I have the anions and cations of the feed seawater and I want to reject the 98,2% of all the anions/cations and know the pH of that fresh water.

 

So I dont know if its possible to introduce the cations/anions of the fresh water and calculate the pH.

 

K = 8,7

Na = 202,01

Mg = 26,72

Ca =8,66

Sr = 0,216

Ba = 0,00018

Cl = 372,96

F= 0,02

SO4 = 53,46

SiO2 = 0,04

B = 0,08

Everything in mg/l

 

So i want to know the pH of the water with that anions/cations

 

I dont know if i am explaining clearly, English is not my main lenguage.

 

 

 

If that choice is in ROSA please tell me where because i didnt find.

Edited by Albertox, 09 January 2019 - 06:58 AM.

[breizh]

Hi ,

Why don't you email to Dupont Tech Service ? They should be happy to support .

 

https://www.dupont.c...er/support.html

 

note : probably good to review the concentration ! mg/l?

 

Good Luck

Breizh

Edited by breizh, 09 January 2019 - 07:39 AM.

[Albertox]

Thank you very much

 

Whats the problem of having the concentration on mg/l?

Edited by Albertox, 09 January 2019 - 07:47 AM.

[breizh]

hi,

the figures look  small, considering sodium and chloride for sea water ! NaCl should be about 3.5% mass .

my 2 cents

Breizh

Edited by breizh, 09 January 2019 - 08:35 AM.

[Albertox]

K, Mg, Ca and SO4 have too much concentration to be honest, but the Na and the Cl concentration is properly for fresh water.

 

I am wrong Na and Cl should be less than 200 and 250 respectly.

Edited by Albertox, 09 January 2019 - 09:14 AM.

[thorium90]

Hope the attachments answer your question.

Attached Files

•  A guide to Rosa 6.pdf   917.29KB   8 downloads
•  Sample.jpg   171.85KB   0 downloads

[Albertox]

You are not understanding my problem. I already know the concentration of cations and anions after the RO module without using ROSA. The only thing i want to know it's whats the pH of the water with that concentration.

 

Probably I dont need ROSA for this but i dont know how can I do.

[thorium90]

The pH of the water is already shown in the last row of the projection. I made a sample and put a red box around the row called pH.

 

If you are asking about the feed water pH, then that is defined when you do a feed study. For example, by taking past data and taking an average.

Edited by thorium90, 09 January 2019 - 10:04 PM.