Trem wrote: > Hi Marshall, > > I had agreed with you to run our SG7 without the electrodes but with the > vigorous stirring the submergible pump provides. It causes the water > surface to be in constant motion so if the water increased conductivity by > absorbing Co2 it should be measurable by using the PWT meter. It didn't > change much...... starting reading was 1.8-2.0 uS as measured with three > meters. End reading was 2.7-2.9 uS. This was in a gallon of DW.
Since equilibrum of CO2 with the atmostphere is at about .58 ppm, if you started with no CO2 in the water and ended up with .58 ppm, which is the maximum unless you are breathing on it, that should increase the conductivity by about .6 to .8 or so in conductance. That is pretty well what you got. > > > I ran the pump for about 18 hours and the reading increased by less than 1 > microsiemen. Since I can produce ionic readings of 45-60 uS using only > distilled water and silver, it appears the reading must be silver ions since > they are the only thing the meter can read other than the little bit of Co2. > Not necessarily. Remember that the stability point of CO2 in the water is about .58 ppm. You seem to have experimentally come up with about the same value. Now as you make EIS, the CO2 forms a carbonate, and the equilibrum shifts toward non saturation. So additional CO2 can be absorbed into the water while making EIS. How much can get made will depend on how fast it gets absorbed, and how long it is run for. That is why the experiments you are doing are important, they can answer these questions. But I think we may need to use pH instead of conductivity for good sensitivity of the absortion rate. > > I didn't drive any Co2 off and do not have a pH measurement for you. My pH > meter may or may not be in calibration at this point so the reading would be > meaningless. The water was taken directly from a gallon of supermarket DW. > I have found that most DW right out of the jug seems to be pretty close to a pH of 7, so not much CO2 is in there. Plus your measurements showed an increase of CO2 concentration of between .5 and 1 ppm, and since the max is .58 ppm, you had to have started with a pretty low amount. I have a pH meter and will try some tests tonight, but I will have to stir the water by hand in my tests. Marshall > > Trem > > ----- Original Message ----- > From: "Marshall Dudley" <[email protected]> > To: <[email protected]> > Sent: Thursday, April 21, 2005 8:16 AM > Subject: CS>CO2 and EIS > > > All previous posts on the composition of EIS have ignored the CO2 > > factor. I have explored this and have some interesting information. > > > > Water at room temperature will equalize with the CO2 present in the > > air. Although air contains about 350 or so ppm of CO2, the water will > > absorb .58 ppm of CO2 before equalizing with the air. The math to > > figure this out can be found at > > http://www.chem.usu.edu/~sbialkow/Classes/3650/Carbonate/Carbonic%20Acid.html > > and other sites list the concentration as about .5 ppm. > > > > Pure water that has equalized with the CO2 in the air will have a pH of > > 5.65. I have found references that report that normal rain is about 5.7, > > so this jives pretty well. > > > > If you leave water in a glass, the surface will quickly equalize with > > the air, but diffusion of the CO2 to below the surface is quite slow. > > So if EIS is produced from water that has stabilized with the air and > > not stirred, the amount of silver carbonate will be about 3.6 ppm. > > > > However if the water is agitated so that the surface layer is > > continually mixed with the rest of the volume, then as CO2 is consumed > > by forming a carbonate, more will be absorbed from the air. If this is > > taken to the limit, then up to 32 ppm of silver carbonate (the > > solubility limit) can be formed. > > > > The unanswered question is just how fast CO2 will be absorbed from the > > air. I believe there is an easy way to tell with any particular setup. > > First take distilled water and check the pH. If it is close to 7 then > > great, if not, then heat it up to boiling to drive off the CO2. Once > > cooled (without stirring), check the pH and it should be around 7. Be > > sure to heat in plastic in a microwave, or glass on the stove, any > > metals will likely add trace contaminates that will affect the pH or act > > as a buffer invalidating the results. > > > > Now place the water into the device for making EIS and run it with NO > > electrodes. Sample the pH over time and record how fast it changes. > > This will give the information as to how fast CO2 is absorbed from the > > air with any particular stirring arrangement. Once we have that > > information, it should be relatively easy to figure out the > > concentration of silver carbonate formed by any device when making EIS. > > Although simply leaving the electrodes, and not running current through > > them may appear to be the same, any silver oxide on the electrodes can > > dissolve and affect the pH. > > > > Marshall > > > > > > > > > > > > -- > > The Silver List is a moderated forum for discussing Colloidal Silver. > > > > Instructions for unsubscribing are posted at: http://silverlist.org > > > > To post, address your message to: [email protected] > > Silver List archive: http://escribe.com/health/thesilverlist/index.html > > > > Address Off-Topic messages to: [email protected] > > OT Archive: http://escribe.com/health/silverofftopiclist/index.html > > > > List maintainer: Mike Devour <[email protected]> > > > > > > > > -- > > No virus found in this incoming message. > > Checked by AVG Anti-Virus. > > Version: 7.0.308 / Virus Database: 266.9.17 - Release Date: 4/19/2005 > > > >
