Degradation Of Methyl Orange By Advanced Oxidation Technology Based On Sulfate Radical

With the development of society,water resources and water environment issues have gradually become a hot issue of social concern.In the wastewater treatment,the resource utilization of printing and dyeing wastewater has become a difficult point in the development of printing and dyeing industry.Printing and dyeing wastewater is easy to cause disposal due to its high biological toxicity and low biodegradability,and it has great potential harm to surface water environment.How to effectively dispose of printing and dyeing wastewater has become a difficult problem to be solved urgently.In this study,the azo dye methyl orange dye in printing and dyeing wastewater was selected as the target substance,and the high-efficiency degradation of methyl orange was achieved by advanced oxidation technology based on sulfate radicals,and the degradation mechanism was explored.The advanced oxidation technology of the base provides a reference for the disposal of printing and dyeing wastewater.In this study,the ferrous iron-activated persulfate degradation of methyl orange was investigated under the condition of no light,and the effects of p H and different concentrations of Cl^-,CO₃^2-,HCO₃^-,NO₃^-and H₂PO₄^-anions on methyl degradation were investigated.The results showed that when the concentration of methyl orange?C?was 10 m M and C: Fe²⁺: PS=1: 4: 12,the removal rate of methyl orange at 5 min and 120 min could reach 42% and 77%,respectively.When C: Fe²⁺: PS=1: 0: 12,the removal rate of methyl orange can reach 56% at 120 min.p H has little effect on the degradation of methyl orange by Fe²⁺/PS system and PS system alone.Different concentrations of NO₃^-had no effect on the degradation of methyl orange in Fe²⁺/PS system.However,Cl^-,H₂PO₄^-,CO₃^2-or HCO₃^-had a certain degree of inhibition on the degradation of methyl orange in Fe²⁺/PS system,and the overall appearance The tendency for inhibition to increase with increasing concentration.The effects of different illumination were explored on the basis of ferrous activated persulfate degradation of methyl orange.The results show that the UV254 illumination is better than the 365 nm illumination.When C: Fe???: PS=1: 4: 12,the removal rate of methyl orange can reach approximately 90% after UV254 illumination for 30 min;In the 94% methyl orange removal rate at 120 min,the hydroxyl radical and sulfate radicals contributed to the degradation of methyl orange by about 4.6% and 24%,respectively.At p H=2,the degradation of methyl orange was promoted under UV254 illumination.The degradation difference was small at p H 3-8,and the inhibition was obvious at p H=10.The degradation of methyl orange in Fe???/PS system at different concentrations of anions Cl^-,NO₃^-,H₂PO₄^-,HCO₃^-,CO₃^2-under UV254 illumination was investigated.The results showed that different concentrations of Cl^-,and NO3 were observed.-There is no effect on the degradation of methyl orange.H₂PO₄^-,HCO₃^-,CO₃^2-show less influence on low concentration,high concentration inhibition and the highest concentration inhibition is not the biggest trend.The degradation of methyl orange by zero-valent iron powder?Fe⁰?activated persulfate was investigated.The results show that Fe⁰ alone has a certain effect on the removal of methyl orange,and the higher the concentration,the better the removal effect.UV254 illumination accelerates the removal of methyl orange from the Fe⁰/PS system.When [PS]=50 m M,[Fe⁰]=0.1 g/L,the removal rate of methyl orange can reach 93% after 154 nm illumination for 15 min,and the degradation effect is better when the p H is not adjusted.The effects of different concentrations of anions Cl^-,NO₃^-,H₂PO₄^-,HCO₃^-,CO₃^2-on the degradation of methyl orange in Fe⁰/PS system under UV254 illumination were investigated.The results showed that the high concentration of anions showed certain Inhibition of the effect,but with the extension of time,the inhibition effect will gradually weaken,the removal rate of methyl orange is higher than 98% at 120 min.When the actual wastewater is treated,the appropriate extension of time can weaken the inhibition of the degradation of methyl orange by anion.The results of toxicity experiments also showed that the Fe⁰/PS system under UV 254 illumination did reduce the biological toxicity of methyl orange to a certain extent,which provided a reference for the future treatment of actual wastewater.