The Characteristics Study On Degradation Of Dye Waste Water Process By Fenton Oxidation

According to high concentration of COD and chroma,complicated ingredients,difficult biochemical degradation and other characteristics in dye wastewater, Byinvestigating the pure water system, acid Fenton red B as the substrate mixed Fentonsystem and alkaline magenta as the substrate mixed Fenton system, OH, ORP, H₂O₂and Fe²⁺change, and its and dyes the corresponding relation of remove oxidation,,thispaper studies some characteristics and laws about Fenton oxidation on removal of acidred B and alkaline magenta.In pure water Fenton system，the system reached a steady state quickly with thereaction of the Fenton system. In the reaction process, the relationship of the of OHforming concentration,△ORP with time could be described as a model ofY abX/1bX. The reaction of H₂O₂、Fe²⁺obeyed the first-order kinetic model ofdC/dt k C Ce. The suitable molar ratio of the H₂O₂/Fe²⁺was1:1，based on theplatform stable value of the OH forming concentration and△ORP and the timerequired to achieve the Maximum△ORP. When H₂O₂/Fe²⁺ratio was2, the OHplatform concentration and Fe²⁺reaction rate constant were maximum. The differenceof the platform stable value of the OH forming concentration between the maximumand the minimum is less than8%, while the difference between the platform stablevalue of the Maximum△ORP was more than83%, which caused by the different ratioof the H₂O₂/Fe²⁺. In the Fenton system, the conversion rate of the Fe²⁺and the H₂O₂was91.7%to98.7%and38.9%to68.4%respectively. The pH and the molar ratio ofthe H₂O₂/Fe²⁺had minor effect on the conversion of the Fe²⁺, but they had greater oneon H₂O₂. The lower H₂O₂conversion rate was corresponding to the lower△ORPplatform.On condition of different H₂O₂/Fe²⁺ratio, in Fenton system the acid red B,H₂O₂and Fe²⁺concentrationfell sharply in a very short time, OH and△ORP risein a veryshort time sharply and gradually tend to be a balance. For the Fenton system ofH₂O₂/Fe²⁺ratio is2:1, it generates large of the high intermediate spectrophotometrymaterials, OH and△ORP value is low. When the H₂O₂/Fe²⁺ratio is in between2:1and6:1in the Fenton system,and the concentration of Fe²⁺is higher,the conversion rateof H₂O₂and Fe²⁺is higher.The best pH for oxidative decomposition of acid red B in theFenton system is3. The low pH is good to the oxidative decomposition of the acid red B, not adverse. In the acidic red B Fenton in the system, the best control to remove dyesoxidation conditions for: pH=3, H₂O₂=34mg L-1, H₂O₂/Fe2+=2:1.When the H₂O₂/Fe²⁺ratio is in between2:1and6:1in the Fenton system, in Fentonsystem the alkaline magenta, H₂O₂and Fe²⁺concentration fell sharply in a very shorttime, OH and△ORP risein a very short time sharply and gradually tend to be abalance. The H₂O₂/Fe²⁺ratio is lower, the conversion rate of H₂O₂and Fe²⁺is higher,the highest conversion rate is corresponding with the H₂O₂/Fe²⁺ratio of1:1. For theFenton system of H₂O₂/Fe²⁺ratio is2:1, it generates large of the high intermediatespectrophotometry materials, OH and△ORP value is low.When the H₂O₂/Fe²⁺ratio isin between1:2and6:1in the Fenton system, The best pH for oxidative decompositionof the alkaline magenta is3, the low pH is good to the oxidative decomposition of thealkaline magenta, vice versa. In alkaline magenta Fenton in the system, the best controlto remove dyes oxidation conditions for: pH=3, H₂O₂=34mg L-1, H₂O₂/Fe²⁺=2:1.As dye consume oxidation species, the OH and△O RPvalue of pure water Fentonsystem is higher than it in dye Fenton the system.The concentration of acid red B andalkaline magenta obeyed the first-order kinetic model ofdC/dt k C Ce.The OHvalue in pure water Fenton system is respectively higher than21.31%and68.05%inalkaline magenta and acidic red B Fenton system.The OH consumption in alkalinemagenta system is much lower than it in acidic red B system. The conversion rate ofH₂O₂are shown as follows:pure water <alkaline magenta <acid red B, the Fe²⁺conversion rate, surplus OH and△O RP value on contrary. In above three system, thechange process of H₂O₂and Fe²⁺accord with dynamics modeldC/dt k C Ce.