Activation Of Persulfate By Modified Carbon Nitride Under Visible Light Irradiation For The Degradation Of Acid Orange 7

In recent years,conventional advanced oxidation processes based on the SO₄^-· received extensive attention of the researchersin the field of environmental treatmen.Compared with HO· induced by traditional advanced oxidation processes,SO₄^-· possesses higher oxidation reduction potential?2.6-3.1V?,and candegrade most biodegradable organic pollutants fully in a widerpH range.Develop effective activation persulfate by metal oxide catalysts is a hotspot of current research.Graphite carbon nitride?g-C₃N₄?is a new type of semiconductor photocatalyst,with similar structure of grapheme layers.The unique chemical structure of g-C₃N₄ unique structure makes it has the advantage of good thermal stability,chemical stability,excellent photoelectric properties,as well as abundant rawmaterials,low cost of preparation and environmentally friendly.g-C₃N₄ used as non-metallic photocatalyst activate peroxymonosulfate?PMS?can overcome the limitation of erosion of active component in oxide antioxidant,but thedefects forg-C₃N₄ of small specific surface area,wide energy bandgap and photoinduced electron hole pairs recombinationeasily,greatly limited its application.In order to promote of g-C₃N₄ activatePMS in visible light,doping modification technology,the semiconductor compound modification technology and control surface area modification technique were used to prepare the three different kinds of modifiedcarbonnitridematerials,X-raydiffraction?XRD?,scanningelectronmicroscopy?SEM?,tr ansmission electron microscope?TEM?,N2adsorption/desorption isotherms,Fourier transform infrared spectroscopy?FT-IR?,X-ray photoelectron spectroscopy?XPS?and UV-visdiffusereflectance spectrumwere applied to characterizethe catalyst,The photocatalytic performance ofg-C₃N₄ activate persulfate to remove acid orange 7?AO7?was studied,the activity of catalyst in different systems andthe influence of reaction conditions on the catalytic effect were investigated and through the radical inhibition experimentsanalyzed main active species and reaction mechanismin the process of AO7 degradation,catalyst stability is also discussed in this article.1)Doping modification technique was used to prepare the iron oxide doped carbon nitride materials?Fe2O3/g-C₃N₄?,according to the characterization,we found that,Fe2O3/g-C₃N₄ has a narrower band gap and higher specific surface area compared than g-C₃N₄.Within 30 min,AO7 dye removal rate of Fe2O3/g-C₃N₄ reached 98.5%,much higher thang-C₃N₄ and alpha Fe2O3,showed that dopingof Fe significantly increased the activity of catalyst.Fe2O3/g-C₃N₄ remained effective activity after 6 times repeated use,indicated that the stability of the catalyst is excellent.By ESR test and free radical inhibiting experiment analyzed the main active species in the reaction process,and presented the mechanism of catalyst activate PMS for the degradation of AO7.2)By the specific surface area control technology,carbon nitride catalysts?CN-HCl?were prepared by melamine hydrochloride under different calcination temperatures.The characterizationmanifested that,the morphology and structure of CN?HCl?transferred from typical layer structure with numerous mesopore to similar thinner layer when the prepared temperature enhanced,with the increaseof BET specific surface areaand the change of the bandgap.The catalytic degradation experiments showed that CN?HCl?/PMS/Vis has good effectfor AO7 decomposition,within 30 min,the degradation rate ofAO7 with CN-550?HCl?reached 96.3%,and the synthesizedtemperaturelargely influenced the activity of the catalyst,at 500 ?,the catalytic effect of CN?HCl?is 1.34 times of CN and it reached3.12 times in 600 ?.Catalyst circulation experiments indicated that the CN-550?HCl?has a good stability and repeatability.The experiment investigated the influence of different kinetic factors on the catalytic performanceand free radical inhibition experiment showed that SO₄^-·is the main active speciesin the CN?HCl?/PMS/Vis system.3)Carbon nitride loaded on activated carbon?AC-CN?HCl??wereobtained by thermal condensation,we researched the photocatalytic effect of different amountof activated carbon loaded.The degradation of AO7 experiments showed that AC-CN?HCl?could not only efficiently activate the PMS to degrade AO7 dye,but also had goodactivation for PS.The effect ofAC-CN?HCl?photoactivate PMS and PS were studied,the effect of reaction conditions on the catalytic effect was investigated respectively,the catalyst of circulatingtrialsproved that AC-CN?HCl?could maintain good stability forthe activation of PMS and PS.the AC-CN?HCl?activation path of PMS and PS were proposed based on the analysisof free radical inhibiting experiments.