To increase the pH value of the desalinated water and determine the amount of ammonia to add, how is this calculated?
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Question: How much 20% ammonia solution needs to be added to 1 liter of pure water with a pH of 7.0 in order to raise its pH to 10.0? Could you please advise on how to calculate this? A detailed calculation process would be ideal. Thank you in advance!
It’s hard to say; based on our experience, when 400 mg/L of ammonia is added to deionized water with very low conductivity, the pH value is approximately 10.0.
This post was last edited by ylb913 on 2015-8-22 at 22:05. The ionization constant of 25-degree ammonia is 1.8*10^(-5), which is equivalent to 10^(-4); therefore, the concentration of ammonia is 0.00056 mol/L. For 20% ammonia, a concentration of 200 g/L corresponds to 200/17 = 11.76 mol/L. The ratio of 0.00056 to 11.76 is 0.000047, meaning that 1 liter of water should be mixed with 0.000047 liters of 20% ammonia.
The simplest and most effective method is to use pilot tests to obtain several sets of data