The unexpected result is the reaction of N2 with O2 to make nitric acid and the low pH. There are entries in the mail archive https://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/mail related to the partial equilibrium system. See particularly an entry related to Yves Dudal for an example of how to disconnect nitrogen gas from equilibrium with nitrate and oxygen. David David Parkhurst (dlpark@xxxxxxxx) U.S. Geological Survey Box 25046, MS 413 Denver Federal Center Denver, CO 80225 Project web page: https://wwwbrr.cr.usgs.gov/projects/GWC_coupled "Pedro Chambel Leitao" <pedro.chambel.maretec@xx To: "David L Parkhurst" <dlpark@xxxxxxxx> guspark.pt> cc: Subject: PHREEQC 05/22/03 08:49 AM Dear David L Parkhurst, I want to simulate pure water in equilibrium with atmosphere (see example below). When I run the example I get a reduction of pH from 7 to 2. Where is my mistake? PS: Is there any discussing group of PHREEQC Best regards Pedro Chambel Leitao ~~~~~~~~~~~~~~~~~~~~~~~~~~ IST - MARETEC Taguspark Nucleo Central, Sala 363 2780-920 Oeiras, Portugal Tel.: +351 21 4239016 Fax: +351 21 4211272 URL: http://www.mohid.com TITLE Test SOLUTION 1 Seawater temp 25 pH 7 pe 18 redox pe units mol/l density 1 -water 1 # kg GAS_PHASE 1 Atmosphere -fixed_pressure -pressure 1 -volume 1 -temperature 25 CO2(g) 0.0003 O2(g) 0.2 N2(g) 0.7797 SAVE solution 1 END -----Original Message----- From: David L Parkhurst [mailto:dlpark@xxxxxxxx] Sent: quarta-feira, 21 de Maio de 2003 14:47 To: Pedro Chambel Leitao Subject: Re: subscribe Ok. Your name will be added to the PHREEQC mailing list.
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