A study on storage stability of sulfite as oxygen scavenger in aqueous solutions

The inhibition of sulfite oxidation by pyrogallic acid was investigated in oxygen scavenging and air oxidation experiments. The results obtained show that Cu2+ as radical initiator accelerate the reaction of sulfite with oxygen and pyrogallic acid as radical absorbent removes the radical produced and thus inhibits the oxidation reaction. The pH value, hardness or alkalinity of the aqueous solutions exert nearly no effect on the inhibition reaction. Using the experimental results a free radical chain mechanism of sulfite oxidation is evidenced again and the way of preventing sulfite solution from failure in storage is suggested.