Study On Persulfate Activation Performances For Refractory Organics Degradation Of Carbon-based Composites

Sulfate-based advanced oxidation technology is an effective method to degrade persistent organic pollutants in wastewater,which has good application prospects.However,persulfate oxidation technology has its certain drawbacks such as low degradation efficiency and secondary pollution,which severely restricts its application in actual wastewater treatmen.In response to these problems,we synthesised coconut shell activated carbon-based cobaltosic oxide（GAC-Co₃O₄）,reduced graphene oxide-based carbon nitride（RC-3）and cobalt-doped graphene aerogel（Co-GA）composite that has both non-radical reaction and free radical oxidation characteristics in persulfate oxidation technology by impregnation-hydrothermal method,thermal polymerization-hydrothermal method and hydrothermal-freeze-drying method,respectively.With the aid of modern techniques of materials characterisation,the material’s microstructure,morphology,physical chemistry and photochemical properties were analyzed.The catalytic performance of the carbon matrix composites was evaluated by the degrading efficiency of methyl orange（MO）,sulfamonomethoxine（SMM）,ciprofloxacin hydrochloride（CIP）,sulfonamides（SN）and Rhodamine B（Rh B）in activating peroxymonosulfate（PMS）or peroxodisulfate（PDS）process,respectively.The thesis will provide technical support for the preparation of carbon-based catalysts and the application of sulfate-based advanced oxidation technology.This thesis mainly encompasses the following concluding remarks:1.Using coconut shell activated carbon（~30 mesh）as raw material,GAC-Co₃O₄ composite material was prepared by impregnation-hydrothermal process.The results indicated that GAC loading can effectively reduce conglobation of Co₃O₄ particles.The efficiency of GAC-Co₃O₄（92.1%）is 1.2 times that of Co₃O₄ in the degradation experiment of PMS oxidizing MO.One possible reason is that GAC acts as an electron transfer carrier,non-radical reactions and free radical oxidation occurred simultaneously in the reaction system.2.The g-C₃N₄ prepared by urea and GO were used to prepare RC-3 composite material that can synergize with visible light to activate PDS to oxidize organic pollutants.The results indicated that the catalytic performance of RC-3（92.3%）was increased to 1.79 times by GO loading.It is attributed to the fact that r GO broadens the photoresponse range and reduces the recombination rate of photogenerated electrons（e^-）-holes（h⁺）.The degradation mechanism of MO is free radical oxidation dominated by SO₄^-·,h⁺and O₂^-·and non-radical reaction initiated by r GO.3.Co-GA composite material is prepared by the hydrothermal-freeze-drying method.The results indicated that the catalytic performance of Co-GA（67%）composite is 2.16 times than that of GA in the activated PMS for SMM degradation,and the degradation rate of CIP,SN and Rh B can reach 73%,83%and 97%,respectively.