How to adjust the pH value?

pH refers to the negative logarithm of the hydrogen ion concentration. When PH = 8, the hydrogen ion concentration is 10^-8 mol/L; when PH = 10, the hydrogen ion concentration is 10^-10 mol/L. The increase in hydrogen ion concentration = 10^-8 – 10^-10 = 9.99^-8 mol/L (the volume of hydrochloric acid added is ignored). Multiplying this value by the flow rate gives 9.99^-5 mol/hr. Since 1 mole of hydrochloric acid provides 1 mole of hydrogen ions, the amount of pure hydrochloric acid required is 9.99^-5 × 36.5 = 0.0036 g/hr. Dividing this value by the concentration of hydrochloric acid yields the amount of hydrochloric acid that needs to be added. The above applies when there are only strong electrolytes in the wastewater; if weak electrolytes are present, hydrogen ions need to establish a new equilibrium, and the amount of hydrochloric acid required will be greater than that calculated above. It is best to analyze the components of the wastewater in order to determine how to adjust the pH.

It can be calculated based on the law of conservation of amount of substance. It’s hydrochloric acid solution that’s being added, right?

Thank you to the people above. Also, what is the concentration of hydrochloric acid used in industry?

The concentration of industrial hydrochloric acid is generally 31%.

Why does such large-scale industrial dynamic production require theoretical calculations? The difference is quite significant; isn’t it better to use online monitoring? Or measure while adjusting with acid.

I agree with you; acid is generated as a result of this reaction. 20% NaOH is added continuously, and the pH value is monitored in real time, allowing for adjustments to the stroke of the alkali metering pump at any time to keep the pH of the medium at a neutral level and prevent corrosion of the equipment and pipelines.

Calculation is the basis. It’s still better to calculate it in advance.

If I don’t do the calculation, I’m not sure what size acid metering pump to choose