Get solution alkalinity

[rjvtww]

Is there a way to retrieve the alkalinity of a solution? I examined the available properties and I cant see it.

In addition, if there is no clear method to do so, is it possible to pass a USER PRINT string and retrieve output to somehow capture it?

Thanks in advance!

[GeertD]

Hi,

Bit of an older issue, but maybe this can help.
I was also looking for the alkalinity.

The databases have Alkalinity as an element:

SOLUTION_MASTER_SPECIES
#element	species	alk		gfw_formula	element_gfw
...
Alkalinity	CO3-2		1.0		Ca0.5(CO3)0.5	50.043

You can therefore add it to a solution:

sol.pp.add_solution({
	'units': 'mmol/kgs',
	'Alkalinity': '150.0',			# 150.0 mmol/kgs
})

But it is not showing up in the list of elements of that solution:

sol.elements
>> {'C(4)': 0.0598, 'H(0)': 1.407e-25}

But we can just perform the standard method to measure the alkalinity:

sol_test = sol.copy()				# take a sample
titer1 = sol_test.total('Cl')
sol_test.change_ph(to_pH=4.5)		# typical endpoint, adds HCl
titer2 = sol_test.total('Cl')
alk = titer2 - titer1				# alkalinity (mmol/kgw)
sol_test.forget()

Would be easy to put that in a method.
I like this even more than the PhreeQC internal calculation, since this is how a lab would do it. It also allows to reach other pH endpoints.