Study On Degradation Of Pollutants In Water By Persulfate Advanced Oxidation Technology

In view of the difficulty of degrading rhodamine B(RhB)and tetracycline contained in sewage,based on the persulfate advanced oxidation technology,which can produce sulfate radicals and hydroxyl radicals with strong oxidizing ability after activation,it is used in water treatment receives more and more attention.Compared with other methods,this technology has the advantages of mild reaction conditions,simple operation,and excellent degradation ability for most pollutants in the water.This article mainly explores the degradation of dye wastewater and tetracycline wastewater by the fluorine-modified transition metal compound vanadium aluminum carbon(F-V2AlC),and the disinfection of persulfate dyes activated by visible light sensitization.The results are as follows:(1)The fluorine-modified transition metal compound vanadium aluminum carbon has good degradation ability for dye wastewater and tetracycline wastewater.In this thesis,the modification of vanadium aluminum carbon with hydrofluoric acid was carried out by mechanical stirring,and X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),specific surface area and pore size analysis(BET)were used.The material was characterized to analyze its physical and chemical properties.Rhodamine B simulated pollutant wastewater was used to conduct comparative experiments to explore the effects of catalyst dosage,persulfate concentration,and pH on the degradation process.The experimental results show that under the same experimental conditions,the reaction rate of V2AlC activated permonosulfate PMS after F modification is 17.8 times higher than that before modification;when the concentration of catalyst F-V2AlC and PMS are 0.15 g/L and 0.2 g/L,respectively is most conducive to the degradation of pollutants,and acidic conditions are more conducive to the progress of the catalytic reaction.Through free radical quenching experiment and electron spin resonance(ESR)test,it is determined that the active substance of the reaction is mainly singlet oxygen(1O2).At the same time,sulfate radical also shows good degradation ability,and the possible path of free radical generation is speculated.In the detection of tetracycline degradation,tetracycline showed different adsorption capacity on the two catalysts,and the intermediate products of tetracycline degradation were tested by Liquid Chromatography Mass Spectrometry(LC-MS).The biotoxicity test of the degraded intermediate product was carried out using E.coli with an initial concentration of 7 log10 cfu/mL.The concentration of E.coli was only reduced by 0.2 log10 cfu/mL,and the degradation intermediate product was basically not bio-toxic.(2)Visible light activates the dye to activate the persulfate to degrade itself and at the same time have a good inactivation effect on bacteria.The concentration of rhodamine B and persulfate was evaluated by the controlled variable method and found that when the concentration of sodium persulfate is 10 mM and the concentration of rhodamine B is 10 mg/L,the inactivation of E.coli and the concentration of rhodamine The degradation of rhodamine B itself has a great promotion effect.In the 60 min experiment under this condition,the degradation rate of rhodamine B reached 83%,and the initial concentration of 7log10 cfu/mL E.coli was inactivated by 6.4log10 cfu/mL.The ESR test detects the active substances in the reaction process,including free radical and non-radical processes.In addition,when there is no light,Rhodamine B has a certain ability to promote persulfate to produce singlet oxygen.The leaked cell contents were identified by fluorescence colorimetry,mainly detecting the leakage of DNA,RNA and K+.As time passed,the amount of leakage continued to increase,with K+reaching 2.1 mg/L.