Preparation Of 3D Graphene-based Heterogeneous Catalyst And Its Application In Refractory Organic Wastewater

Graphene is a new type of carbon-based material emerging in recent years.Due to its excellent properties such as large specific surface area and high mechanical strength,graphene has good application prospects in integrated circuits,composite materials,and biomedicine.Three-dimensional graphene is a substance with a three-dimensional structure composed of two-dimensional graphene.It has a high specific surface area and three-dimensional pore structure,which enhances its adsorption capacity.At the same time,the three-dimensional structure solves the agglomeration and stacking of two-dimensional graphene sheets defect.Clays such as montmorillonite,kaolin,bentonite,and attapulgite have been used as natural cost-effective carriers for heterogeneous catalysis in wastewater treatment.Attapulgite?ATP?has a unique fiber morphology and is a hydrous magnesium-rich aluminosilicate clay mineral.In view of its unique structure,ATP has a large surface area and exhibits excellent adsorption performance and catalytic activity,which makes it possible to be widely used as an adsorbent and catalyst carrier.In this thesis,two heterogeneous catalysts:Fe₂O₃/ErGO and Fe₂O₃/rGO-ATP were prepared using graphene oxide as a carrier.These two catalysts were used in the study of the catalytic degradation of dye wastewater and antibiotic wastewater.The degradation mechanisms of MB and CIP were studied and analyzed.The specific research content is as follows:?1?Using ethylenediamine as the reducing agent,hydrothermal and chemical reduction methods are used to prepare Fe₂O₃/ErGO catalysts by supporting Fe₂O₃ as the active component on the carrier.SEM,BET,FT-IR,XRD,XPS,etc Characterization means analyzed its morphology,structure and composition.After the reduction of ethylenediamine and the support of Fe₂O₃,the specific surface area of the catalyst increases,and the characteristic peaks of Fe₂O₃ appear in the prepared catalyst,which proves that Fe₂O₃ exists in the catalyst.The effects of operating conditions on the catalytic performance of the catalyst Fe₂O₃/ErGO were studied with MB and CIP as the target pollutants.The reuse performance was investigated,and the kinetic equation fitting was performed for the degradation process.The results show that when MB is the target pollutant,the initial concentration of MB is 50mg/L,the concentration of H₂O₂ is 0.9908mmol/L,the dosage of catalyst is 1.0g/L,the reaction temperature is 60°C,and the pH is 5,The degradation rate of methylene blue by Fe₂O₃/ErGO can reach more than 99%.When CIP is used as the target pollutant,the catalyst dosage is 1.0g/L,pH=5,temperature is 60°C,H₂O₂ concentration is2.477mmol/L,and the initial concentration of wastewater is 50mg/L,The degradation rate can reach more than 90%.Cyclic degradation experiments of two pollutants show that the catalyst has a certain reusability.?2?A one-step hydrothermal reduction method was used to prepare a new catalyst Fe₂O₃/rGO-ATP by supporting Fe₂O₃ and ATP,and its morphology,structure,composition,etc.were characterized by means of SEM,BET,FT-IR,XRD,XPS Analyzed.The loading of active materials Fe₂O₃ and ATP increased the specific surface area,formed a three-dimensional pore structure,improved the catalytic performance of the catalyst,and the characteristic peaks of Fe₂O₃ and ATP appeared at the same time,indicating that Fe₂O₃ and ATP were successfully loaded.The effects of operating conditions on the catalytic performance of the catalyst Fe₂O₃/rGO-ATP were studied with MB and CIP as the target pollutants.The reuse performance was investigated,and the kinetic equation fitting was performed for the degradation process.The results show that when MB is the target pollutant,the amount of catalyst used is 1.0g/L,the concentration of H₂O₂ is 2.477mmol/L,pH=5,the temperature is60°C,and the initial concentration of MB is 50mg/L.The degradation rate of MB by catalyst Fe₂O₃/rGO-ATP reached almost 100%.When the target pollutant is CIP,when the catalyst dosage is 1.0g/L,pH=5,temperature is 60°C,H₂O₂ concentration is2.9724mmol/L,and the initial concentration of wastewater is 50mg/L,The degradation rate of methylene blue by Fe₂O₃/rGO-ATP can reach 90%.Cyclic degradation experiments of two pollutants show that the catalyst also has reusable performance.?3?Analyze the mechanism of heterogeneous catalyst Fe₂O₃/ErGO degradation of MB.When the reaction system is a heterogeneous Fenton system,the immobilized Fe₂O₃ catalyzes the decomposition of H₂O₂ to generate·OH radicals,thereby oxidizing the MB to decolorize it.Catalytic degradation of MB is achieved.When H₂O₂ does not exist in the reaction system,due to the three-dimensional structure of Fe₂O₃/ErGO,the catalyst Fe₂O₃/ErGO quickly adsorbs MB,and then catalyzes O₂ and H₂O to·O₂^-,which decolorizes MB and achieves MB Catalytic degradation.The intermediate products of Fe₂O₃/rGO-ATP degradation of CIP were analyzed and a possible degradation pathway was deduced.