Dear Crispin, I think this does pertain to 'stoves' in regard to biochars produced and use in ag related additives and water treatment because IMO people put much too much emphasis in a pH measurement. It means little when one looks at how the value is being used. The pH value of biochars, soil and water mean little (except for what it is at that moment) because when a pH is determined it is what's needed to change that pH to what one wants or what that pH has regarding potential of doing is the info we really want. So the right pH we walk away happy but the wrong pH and we need a lot more info to make corrections.
To measure the pH of the ocean to 0.1 pH units seems impossible. Not sure I could do it in the lab using our 4 pH meters and all using the same buffers to calibrate. That because the pH constantly drifts with solubility of gases, changes in microbial activity, temperature differences and pH electrode activity etc. And we think we can measure the pH of the ocean with all the currents, planktons, temperature variations, depth and turnovers etc to a 0.02 units for an accurate 0.1 value?!! And then we have CO2 being taken up by plants and chemical activity and released in varying stages - in an ocean of water.... Like climate change and glaciers I think a better indicator would be shell destruction as mentioned in that excellent video Peter attached. Or a measure of alkalinity (titrating to pH 4.5) or, perhaps the aggressive index, ryzner indix, langlier index that includes many other factors placing water between a scale of aggressive at one end and scale forming at the other. Then people use the pH reading to determine the change in hydrogen concentration? When there are so many hydrogen sinks and release in many configurations. But I am sure at a pH of 8.3 it will take up a lot of the CO2 we produce - good for land but not for the oceans. http://en.wikipedia.org/wiki/Langelier_Saturation_Index#Langelier_Saturation _Index_.28LSI.29 http://www.krwa.org/docs/Aggressive%20Index%20Formula.pdf http://www.lenntech.com/calculators/langelier/index/langelier.htm http://www.lenntech.com/calculators/ryznar/index/ryznar.htm I have never used these on ocean water but domestic water we determine if the water is aggressive and will eat the pipes OR if the water is scale forming and will place a layer of calcium carbonate coating protecting the pipe. The calcium carbonate is the same make-up as shells so should predict the same I would think. We go for slightly scale forming so to protect pipes but not fill them up with lime deposits. The pH of Biochar means nothing unless we give it a lime equivalent (carbonate as CaCO3) and/or neutralizing value (back titrate an acid to pH 8.3 as CaCO3) to relate an application rate to liming and predict what it will do to the soil. As for the calculations; I was looking for a paper I wrote explaining this to clients to attach to this e-mail but it might be at home or lost as it was 30+ years ago. Regards Frank -----Original Message----- From: Stoves [mailto:[email protected]] On Behalf Of Crispin Pemberton-Pigott Sent: Saturday, July 06, 2013 1:26 AM To: Stoves Subject: Re: [Stoves] on ocean acidification Dear Frank I want to get the math of this correct. The claim is that the oceans have changed pH from 8.2 to 8.1, that this is (at least in part or totally) caused by human emissions of CO2, right? And further that this represents a '30% increase in acidity'. The method described asserts that it is a logarithmic scale and that the 30% and the term 'acidity' are appropriate. I would like to put this in perspective. If the 'acidity' rose 15,800% then the oceans would be Neutral, neither acidic nor alkaline using conventional terminology. As oceans vary from about 8.4 to 7.8 that is a natural variation of '400%', using the same definition as is applied in the case of '30%'. In the case of rain, which has a CO2 content of over 10,000 ppm it is '50,000% more acidic' than ocean water at pH 8.2. In fact rain really is acidic. Seems to me that if '30%' is catastrophic the EPA should ban rainfall with immediate effect. It is obviously wrecking the ocean. Regards Crispin >From BB9900 -----Original Message----- From: "Frank Shields" <[email protected]> Sender: "Stoves" <[email protected]> Date: Fri, 5 Jul 2013 10:29:22 To: 'Discussion of biomass cooking stoves'<[email protected]> Reply-To: Discussion of biomass cooking stoves <[email protected]> Subject: Re: [Stoves] on ocean acidification This is a very good topic and related to Stoves to the point of noting the difference of a measure of Biochar pH value and alkalinity value. The pH is really not that important as many think it is. It's the alkalinity that is important. Having a water with a pH of 8.3 takes little acid to lower the pH but toss in a chunk of lime and the pH is still 8.3 but you will need to add acid until all the lime is dissolved before the pH goes down. So pH is just a reading. Alkalinity (or neutralizing value) is a measure of the amount of buffering holding that pH. We report this as CaCO3 equivalent units so it can be compared to adding limestone to a soil. We boil a Biochar sample in 100 mls of 0.5N HCl to dissolve all the carbonates and oxides in the sample then back titrate using NaOH to determine the amount buffering (or neutralizing value) the sample has. Much more useful. Frank Thanks Frank Shields BioChar Division Control Laboratories, Inc. 42 Hangar Way Watsonville, CE 95076 (831) 724-5422 tel (81) 724-3188 fax [email protected] www.controllabs.com -----Original Message----- From: Stoves [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, July 04, 2013 11:47 PM To: Discussion of biomass cooking stoves Subject: Re: [Stoves] on ocean acidification On Thu, 04 Jul 2013 23:21:20 -0600,Mark Bigland-Pritchard / Low Energy Design Ltd <[email protected]> wrote: >I wouldn't normally want to post off-topic, but I think it is necessary >that an error be corrected before this thread is put to sleep. Mark I'm happy with your correction explaining pH. As we generally do use pH to denote acidity rather than hydrogen ions I think it is misleading to then say a 30% increase in hydrogen ion activity equates to a 30% change in acidity. I think change in ocean ecology due to this small change in pH is a very serious concern but please all of you take the discussion elsewhere and stick to stove issues. AJH _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists .org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/ _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
