Influence of multi-point addition of H₂O₂ on ORP of Fe²⁺/H₂O₂ system

In Fenton system, invalid consumption of hydroxyl radicals was directly influenced by adding ways of H₂O₂. Therefore, influence of multi-point addition of H₂O₂ on ORP of Fe²⁺/H₂O₂system was experimentally studied and analyzed in this work. Results indicate that final ORP of system was higher when H₂O₂ was added by more points. Fe³⁺/Fe²⁺ was the main contribution substances. When hydroxyl radicals were captured, ORP of system would increase, which was attributed to change of circulation state of Fe³⁺/Fe²⁺. Invalid consumption of hydroxyl radicals by H₂O₂ was enhanced with increased temperature, which caused change of circulation state of Fe³⁺/Fe²⁺. Change process of ORP and final ORP was impacted by adding time scale of H₂O₂. When H₂O₂ was added within 4 min, Fenton system achieved highest final ORP, which showed in other conditions, Fe²⁺ could not be transferred to Fe³⁺ adequately; final ORP was lower and needed a longer time to reach stable level.