I am faced with an issue involving possible carbon dioxide entrainment in a NaCl buffer used for constant volume diafiltration. The CO2 originates from filtered compressed air used throughout processing. My question concerns the extent of impact on the pH and buffering capacity of this NaCl (<1% w/w) solution. Would entrainment of CO2 from head space air in vessels and piping cause a major shift in the pH of such a salt solution or not make much difference? Could you also provide any links where I may find information regarding pH effects of CO2 gas on salt solutions of low ionic strength?
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John Corn Forum Moderator 6 Posts
Re:15 July 2005 at 1:29pmAir contains about 300 ppm of CO2 and the effect of CO2 in air on the pH of distilled water can be readily calculated (might be able to look it up in published literature). As a first pass, the presence of NaCl (salt of a strong acid and strong base) would level the pH effect somewhat. Thus we would have placed some boundaries on the effect. Next, I would use a process simulator that has an ionic solution option (and enable the pH calculation switch) to see if some additional guidance can be had.