Can sodium sulfite be used as a reducing agent for RO?
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Can sodium sulfite be used as a reducing agent for RO? What is the specific amount to add? I hope experienced sea travelers can provide an answer; thank you!
It is sodium hydride that is used to reduce free chlorine. Generally, the ORP signal is used in conjunction with the sodium sulfite dosing pump to automatically adjust the dosage, thereby keeping the residual chlorine level before entering the membrane at less than 0.1 PPM.
It should work, but sodium bisulfite is more commonly used in engineering applications; perhaps sodium bisulfite has a shorter shelf life, though the exact reason is unknown. As for the dosage, the empirical value for sodium bisulfite is 3 ppm added to achieve 1 ppm of residual chlorine; given that the molar ratio of sodium bisulfite to sodium sulfite is 1:1, the dosage of sodium sulfite should also be 3 ppm added to achieve 1 ppm of residual chlorine. This post was last edited by tjsong on 2009-2-18 17:43]
Upstairs, what kind of conclusion is that – “based on a molar ratio of sodium bisulfite to sodium sulfite of 2:1”? Do you mean sodium metabisulfite? 1 mol of sodium metabisulfite and 1 mol of water can produce 2 mol of sodium bisulfite. Sodium pyrosulfite has the molecular formula Na2S2O5; sodium bisulfite is NaHSO3, while sodium sulfite is Na2SO3.
The reducing power of sodium bisulfite and sodium sulfite should be the same in theory.
Sorry, I made a mistake; it should be 1:1, they are the same.
Adjust the addition amount based on the ORP value
Theoretical ratio of sodium perchlorate to sodium bisulfite is 1:1.8, while the empirical ratio is 1:3. Of course, this is just based on experience; it would be best to have an ORP measurement. It’s clear at a glance
There is no problem-solving approach for this; first, it is necessary to determine the amount of sodium hypochlorite to be added, and then the amount of reducing agent to be used is determined based on the residual chlorine level (Dow requires residual chlorine to be less than 0.1 ppm) or ORP value (which should be less than 300)
Dosage is carried out based on the actual ORP, with an ORP range of -100 to 100