[IronShirt]

Hi! I'm using high level of sodium metabisulphite in my reaction and need to neutralize the excess bisulphite before releasing it into drain.
I'm planning to use hydrogen peroxide but how can I estimate how much is required? Is there a way to estimate the amount of bisulphite in the solution?
Michael

[rolnor]

Bisulfite is not very toxic? Are you working i kg-scale?

[IronShirt]

yep, large scale enough to likely cause problems in waste water treatment

[rolnor]

So you need to go from NaHSO3 to NaHSO4? How much H2O2 is needed?

[IronShirt]

Yes, aiming to make sulphate so solution does not act like biocide any more. But could one estimate the amount of H2O2 required in order to get rid of red/ox potential? Part of the bisulfite will be consumed in the previous reaction so all of it is not present any more.

[chenbeier]

You take a sample of your bisulfite solution and do an analysis of it. If you know the moles, then you can calculate 1 mole HSO₃^- requires 1 mole H₂O₂.

[billnotgatez]

Just wondering why H₂O₂ as opposed to NaOH or something else.

[Borek]

Just wondering why H₂O₂ as opposed to NaOH or something else.

Because OP doesn't want to end with a sulfite (which is reducing agent) but with sulfate (reasonably inert).