Soil chemical reaction at negative temperature

The HP1 code incorporates modules simulating
(1) transient water flow in variably-saturated media,
(2) transport of multiple components, and
(3) mixed equilibrium/kinetic geochemical reactions.
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Soil chemical reaction at negative temperature

Post by wuhanuniversity0416 » Fri Jan 07, 2022 1:53 pm

Can HP1 calculate the movement of water and salt in soil when the soil temperature is below 0 ℃? Is it possible to calculate the chemical reaction of salt ions in soil under these conditions, such as precipitation and dissolution?

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Re: Soil chemical reaction at negative temperature

Post by Jirka » Fri Jan 07, 2022 6:45 pm

I do not know if PHREEQC can handle subzero temperatures, but HYDRUS (the flow part) cannot. J.

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Re: Soil chemical reaction at negative temperature

Post by diederik » Sun Jan 09, 2022 9:33 pm

I never worked with temperatures below 0°C. Please check papers that describe geochemical modelling for low-temperature systems with PHREEQC (note: starting form PHREEQC 3.3.11 - an official HP version with the most recent version (at least PHREEQC 3.7) will be released soon)

Version 3.4.0: November 9, 2017 (svn 12927)
svn 12839
PHREEQC: ColdChem.dat database has been expanded to include sulfate and sulfate
salts. The database is described in a new journal article by Toner and Catling:
Journal of Chemical & Engineering Data, 2017,

Version 3.3.11: March 10, 2017 (svn 12535)
svn 12480
PHREEQC: Added the ColdChem.dat database developed by Toner and
Catling, Journal of Chemical & Engineering Data, 2017, DOI: 10.1021/
acs.jced.6b00812. It is a comprehensive Pitzer model in the Na-K-Ca-Mg-
Cl system valid for low temperature, from 298.15 to < 200 K.
PHREEQC was modified to allow definition of the temperature dependence
of A(phi) in the Pitzer formulation through a new option, -APHI, in
the PITZER keyword. The coefficients of the APHI expression are the
same as the temperature dependence of other Pitzer parameters.
A new Basic function, APHI, has been added to give the value of
the parameter in the current calculation.

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