def test_effective_pitzer_mgcl2_activity(self):
# test the activity coefficient of MgCl2
# corresponds to 0.515m, 1.03m, 2.58m, and 4.1m
multiple = [1, 2, 5, 8]
expected = [0.5, 0.5, 0.67, 1.15]
# import the parameters database
from pyEQL import paramsDB as db
for item in range(len(multiple)):
s1 = self.mock_seawater(multiple[item])
Salt = pyEQL.salt_ion_match.Salt('Mg+2', 'Cl-')
db.search_parameters(Salt.formula)
param = db.get_parameter(Salt.formula,
'pitzer_parameters_activity')
alpha1 = 2
alpha2 = 0
molality = Salt.get_effective_molality(s1.get_ionic_strength())
temperature = str(s1.get_temperature())
activity_coefficient=pyEQL.activity_correction.get_activity_coefficient_pitzer(s1.get_ionic_strength(), \
molality,alpha1,alpha2,param.get_value()[0],param.get_value()[1],param.get_value()[2],param.get_value()[3], \
Salt.z_cation,Salt.z_anion,Salt.nu_cation,Salt.nu_anion,temperature)
# convert the result to a rational activity coefficient
result = activity_coefficient * (
1 + pyEQL.unit('0.018 kg/mol') * s1.get_total_moles_solute() /
s1.get_solvent_mass())
#print(result,expected[item])
self.assertWithinExperimentalError(result, expected[item],
self.tol)
def test_effective_pitzer_mgcl2_activity(self):
# test the activity coefficient of MgCl2
# corresponds to 0.515m, 1.03m, 2.58m, and 4.1m
multiple = [1,2,5,8]
expected=[0.5,0.5,0.67,1.15]
# import the parameters database
from pyEQL import paramsDB as db
for item in range(len(multiple)):
s1 = self.mock_seawater(multiple[item])
Salt = pyEQL.salt_ion_match.Salt('Mg+2','Cl-')
db.search_parameters(Salt.formula)
param = db.get_parameter(Salt.formula,'pitzer_parameters_activity')
alpha1 = 2
alpha2 = 0
molality = Salt.get_effective_molality(s1.get_ionic_strength())
temperature = str(s1.get_temperature())
activity_coefficient=pyEQL.activity_correction.get_activity_coefficient_pitzer(s1.get_ionic_strength(), \
molality,alpha1,alpha2,param.get_value()[0],param.get_value()[1],param.get_value()[2],param.get_value()[3], \
Salt.z_cation,Salt.z_anion,Salt.nu_cation,Salt.nu_anion,temperature)
# convert the result to a rational activity coefficient
result = activity_coefficient * (1+pyEQL.unit('0.018 kg/mol')*s1.get_total_moles_solute()/s1.get_solvent_mass())
#print(result,expected[item])
self.assertWithinExperimentalError(result,expected[item],self.tol)
def __init__(self, formula, amount, volume, solvent_mass, parameters={}):
"""
Parameters
----------
formula : str
Chemical formula for the solute.
Charged species must contain a + or - and (for polyvalent solutes) a number representing the net
charge (e.g. 'SO4-2').
amount : str
The amount of substance in the specified unit system. The string should contain both a quantity and
a pint-compatible representation of a unit. e.g. '5 mol/kg' or '0.1 g/L'
volume : pint Quantity
The volume of the solution
solvent_mass : pint Quantity
The mass of solvent in the parent solution.
parameters : dictionary, optional
Dictionary of custom parameters, such as diffusion coefficients, transport numbers, etc. Specify
parameters as key:value pairs separated by commas within curly braces, e.g.
{diffusion_coeff:5e-10,transport_number:0.8}. The 'key' is the name that will be used to access
the parameter, the value is its value.
"""
# import the chemical formula interpreter module
import pyEQL.chemical_formula as chem
# check that 'formula' is a valid chemical formula
if not chem.is_valid_formula:
logger.error("Invalid chemical formula specified.")
return None
else:
self.formula = formula
# set molecular weight
self.mw = chem.get_molecular_weight(formula) * unit("g/mol")
# set formal charge
self.charge = chem.get_formal_charge(formula)
# translate the 'amount' string into a pint Quantity
quantity = unit(amount)
self.moles = quantity.to("moles",
"chem",
mw=self.mw,
volume=volume,
solvent_mass=solvent_mass)
# trigger the function that checks whether parameters already exist for this species, and if not,
# searches the database files and creates them
db.search_parameters(self.formula)
def __init__(self,formula,amount,volume,solvent_mass,parameters={}):
'''
Parameters
----------
formula : str
Chemical formula for the solute.
Charged species must contain a + or - and (for polyvalent solutes) a number representing the net charge (e.g. 'SO4-2').
amount : str
The amount of substance in the specified unit system. The string should contain both a quantity and
a pint-compatible representation of a unit. e.g. '5 mol/kg' or '0.1 g/L'
volume : pint Quantity
The volume of the solution
solvent_mass : pint Quantity
The mass of solvent in the parent solution.
parameters : dictionary, optional
Dictionary of custom parameters, such as diffusion coefficients, transport numbers, etc. Specify parameters as key:value pairs separated by commas within curly braces, e.g. {diffusion_coeff:5e-10,transport_number:0.8}. The 'key' is the name that will be used to access the parameter, the value is its value.
'''
# import the chemical formula interpreter module
import pyEQL.chemical_formula as chem
# check that 'formula' is a valid chemical formula
if not chem.is_valid_formula:
logger.error('Invalid chemical formula specified.')
return None
else:
self.formula = formula
# set molecular weight
self.mw = chem.get_molecular_weight(formula) * unit('g/mol')
# set formal charge
self.charge = chem.get_formal_charge(formula)
# translate the 'amount' string into a pint Quantity
quantity = unit(amount)
self.moles = quantity.to('moles','chem',mw=self.mw,volume=volume,solvent_mass=solvent_mass)
# trigger the function that checks whether parameters already exist for this species, and if not,
# searches the database files and creates them
db.search_parameters(self.formula)
