Study On The Removal Characteristics And Mechanism Of Halobenzoquinone In Drinking Water By Advanced Oxidation

In recent years,people's living and production levels have continued to increase,and the amount of domestic sewage and industrial wastewater has been increasing.Some wastewater is directly discharged into rivers,which ultimately pollutes drinking water sources.In order to improve the safety of drinking water microorganisms,disinfectants such as chlorine,chloramine,chlorine dioxide,and ozone need to be added for disinfection,but disinfectants and organic matter in water will generate disinfection byproducts?DBPs?.Halogenated benzoquinone?HBQs?is a new type of uncontrolled DBPs,which has been detected frequently in drinking water in recent years.Although its content is only ng/L,its toxicity is much higher than that of conventional DBPs,which has a huge potential risk to the safety of drinking water.Therefore,it is necessary to carry out the research on the removal of halogenated benzoquinone from drinking water to further ensure the safety of drinking water.In this experiment,2,6-dichloro-1,4-benzoquinone?DCBQ?,which has the highest content and detection frequency in actual water,was selected as the target pollutant.Adopt UV/O₃,O₃/H₂O₂,UV/H₂O₂,UV/H₂O₂/O₃ advanced oxidation technology to carry out the experimental research on the removal effect of DCBQ.UV/O₃,O₃/H₂O₂,and UV/H₂O₂ advanced oxidation technologies were used to carry out experimental research and kinetic analysis on the removal effect of DCBQ by UV/O₃,O₃/H₂O₂,and UV/H₂O₂.Then used UV/H₂O₂/O₃ advanced oxidation technology UV/H₂O₂/O₃,and used response surface methodology to conduct experimental design to investigate the influence of UV dose,O₃ and H₂O₂ concentration changes and the interaction between these factors on DCBQ degradation Research on the influence of inorganic anions(Cl^-,NO₃^-,HCO₃^-,CO₃^2-)and NOM on the degradation of DCBQ,and the intermediate products and degradation pathways of DCBQ were analyzed.At last,the effluent from the floatation-sand filtration process in the pilot test base of Quehua Water Plant in Jinan City?the raw water is the water from the Yellow River Reservoir?was labeled with DCBQ as the research object.The experiment used UV/H₂O₂/O₃ technology to study the removal characteristics of organic matter in water after standard DCBQ filtration,compared the actual water sample test and pure water sample test results,explored the changes of pH,UV₂₅₄,turbidity,analyzed the UV/H₂O₂/O₃ oxidation in the process of organic molecular weight distribution,solubility fluorescence material,soluble organic matter composition,THMs formation potential change.The relevant research results are as follows:?1?When the UV dosage is 180 mJ/cm²,H₂O₂?O₃ dosage is 2 mg/L,The removal rates of DCBQ by UV,H₂O₂ and O₃ technologies were 36.1%,32.0%and 57.9%,respectively.?2?When O₃ dose and H₂O₂ dosage are 2 mg/L,the UV dosage is 180 mJ/cm²,the combination technology of UV/H₂O₂ and UV/O₃ has the best removal effect on DCBQ,and O₃/H₂O₂ dosage and H₂O₂ dosage are 2 mg/L and 1 mg/L respectively.Under the optimal conditions,the removal rates of DCBQ by UV/H₂O₂,O₃/H₂O₂ and UV/O₃ technologies were88.5%,96.7%and 99.7%,respectively,and the reaction rate constants were 0.39688,0.50685 and0.67747 min^-1,respectively.With the increase of the addition amount of H₂O₂ and O₃,the removal rate and reaction rate of DCBQ increased.The removal effect of three technologies on DCBQ was ranked as:UV/O₃>O₃/H₂O₂>UV/H₂O₂.?3?The correlation coefficient R²>0.98 of the quadratic model with the removal rate of DCBQ as the response value indicated that the experimental data were in good agreement with the model.The order of influence of O₃ concentration,UV dose and H₂O₂ concentration on DCBQ removal rate was:O₃ concentration>UV dose>H₂O₂ concentration.The optimal operating conditions were as follows:UV dose was 180 mJ/cm²,O₃ concentration was 0.51mg/L,and H₂O₂concentration was 1.36mg/L.There is little difference between the actual value and the predicted value,and the model has good practicability and reliability.?4?Several intermediates including ho-dcbq,DCBT,HO-DCBQ and DCBQ were detected in the intermediate test,and the degradation pathway of DCBQ in the advanced oxidation process was proposed.?5?The test results show that Cl^-,NO₃^-,HCO₃^-,and CO₃^2-inorganic anions all had a certain inhibitory effect.With the increase of anion concentration,the inhibition was more obvious.Lower HA concentration will promote the oxidation of DCBQ and increase the removal rate of DCBQ,while higher HA concentration will inhibit the oxidation of DCBQ.UV/H₂O₂/O₃technology is suitable for removing DCBQ in water.Compared with UV/H₂O₂,H₂O₂/O₃ and UV/O₃ technologies,the application of UV/H₂O₂/O₃ technology can guarantee the removal effect of DCBQ,reduce the addition of O₃ and H₂O₂,reduce the cost,and is more suitable for the production practice.?6?The test results show that the actual water sample test has a good removal effect on DCBQ;the pH and turbidity decrease slightly;the average removal rate of UV₂₅₄54 is 55.3%,and the aromaticity in water decreases.After degradation by UV/H₂O₂/O₃ technology,the macromolecular organic matter in the water is degraded into small molecular organic matter,the molecular structure of the organic matter is changed,the content of soluble fluorescent substances and soluble organic matter components decreases,and THMsFPs increases slightly.Through this study,UV/H₂O₂/O₃ technology is an effective method to remove DCBQ in drinking water.