Hydrogen Peroxide Decomposition in an Environmentally Friendly Pickling Solution for AISI 316L Stainless Steel Available to Purchase

There is increasing interest in the utilization of ecological bath solutions for the pickling of stainless steel (SS), because conventional nitric (HNO₃) and hydrofluoric (HF) acid mixtures generate high NO_x emissions. A mixture of hydrogen peroxide (H₂O₂), sulfuric acid (H₂SO₄), and HF has been tested in this study as an environmentally friendly pickling solution for AISI 316L SS (UNS S31603). The decomposition of H₂O₂ and the H₂SO₄-HF-H₂O₂ mixture was assessed at different temperatures from 25°C to 60°C, with ferric ion contents from 0 to 40 g/L, with and without stirring of the aqueous acid mixture. The p-Toluene sulfonic, 3-hydroxybenzoic, and 4-dodecylbenzene sulfonic acids were tested as stabilizers for H₂O₂. The AISI 316L SS pickling rate found at 50°C was 2.35 × 10³ mg/dm²-day (mdd) and 0.12 × 10³ mdd, respectively, in the absence and presence of 40 g/L ferric ion.