Experimental Study On Degradation Of Rhodamine B By Advanced Oxidation Technology Based On Iron

The pollution of dye wastewater to the water environment has become increasingly serious.According to reports,China emits up to 1%of dye wastewater annually 1×10⁹～1.46×10⁹tons,characterized by high chromaticity,strong carcinogenicity,and difficulty in degradation,have become one of the key treatment targets for environmental pollution control.Advanced oxidation process（AOPs）have become the preferred method to treat organic wastewater because of their controllable reaction process,simple operation,excellent treatment effect,low cost and other characteristics.This topic selects the representative azo dye rhodamine B（Rh B）as the target pollutant,and uses persulfate Advanced oxidation process and emerging percarbonate Advanced oxidation process to treat Rh B wastewater respectively.The control variates was used to conduct a single factor experiment on the two Advanced oxidation process,and the impact of inorganic salt anions on the two technologies was explored by adding inorganic salt anions.Finally,the feasibility study of the two technologies for degrading Rh B was verified through tap water experiments and actual water experiments.The research results indicate that:Under the conditions of p H=3,PS=150 mg/L,Fe⁰=40 mg/L,and T=30℃,the Fe⁰/PS system can degrade 81%Rh B within 60 minutes;The system conforms to a second-order kinetic model when degrading Rh B.It was found that the degradation effect of Fe⁰/PS system decreased with the increase of p H;When the concentration of PS is constant,the Rh B degradation rate increases with the increase of Fe⁰ dosage,while when Fe⁰ dosage is excessive,the Rh B degradation rate actually decreases;When the concentration of Fe⁰ is constant,the higher the concentration of PS,the better the degradation effect.By adding common inorganic salt anions to the system,it was found that different anions have different effects on the system.The inhibitory effect is more significant,and the order of inhibition is as follows:HCO₃^->Cl^->SO₄^2->NO₃^-;By adding an appropriate amount of sodium sulfite to the solution through different dosing methods,the degradation effect of the system was improved.The results showed that the segmented dosing method was more effective in enhancing the degradation effect of Rh B in the Fe⁰/PS system;Although Rh B has a high degradation rate,its mineralization degree is relatively low,and most of it has been transformed into intermediate products,and has not been completely degraded into CO₂ and H₂O;Through experiments in different water bodies,it has been confirmed that the system can degrade Rh B,and the degradation effect under tap water conditions is better than that under sewage conditions.At the same time,the improvement effect of sodium sulfite was verified in this experiment.Through quenching experiment,it was proved that there were two active species in the reaction,namely hydroxyl and sulfate radical,and sulfate radical played a dominant role.The Fe²⁺/SPC system can degrade 96%Rh B within 10 minutes under conditions of p H=3,SPC=0.025 g,Fe²⁺=0.1 g,and T=30℃;And the degradation of Rh B in the Fe²⁺/SPC system follows a second-order kinetic model.It was found that the degradation effect of Fe²⁺/SPC system decreased with the increase of p H;When the concentration of SPC is constant,the Rh B degradation rate increases with the increase of Fe²⁺dosage,while when Fe²⁺dosage is excessive,the Rh B degradation rate actually decreases;When the concentration of Fe²⁺is constant,the higher the concentration of SPC,the better the degradation effect.When excessive SPC is added,the Rh B degradation rate is actually inhibited.By adding common inorganic salt anions to the system,it was found that different anions have different effects on the system.The inhibitory effect is more significant,and the order of inhibition is as follows:HCO₃^->SO₄^2->Cl^-=NO₃^-;Although Rh B has a high degradation rate,its mineralization degree is relatively low,and most of it has been transformed into intermediate products,and has not been completely degraded into CO₂ and H₂O;Through experiments in different water bodies,it has been confirmed that the system can degrade Rh B,and the degradation effect under tap water conditions is better than that under sewage conditions.Through quenching experiment,there are two active species of hydroxyl and superoxide radical in the system,and hydroxyl radical occupies the dominant position.