Synthesis Of Atomic-Scale Cu,Fe-Based Catalysts And Removal Study Of Aromatic Organic Pollutants

The widespread release of various chemicals used in industrial production into the environment has led to the generation of emerging pollutants,resulting in an increasingly complex composition of water pollutants.Among them,the excessive use of halogenated antibiotics and phenolic compounds has received increasing attention due to their widespread distribution and frequent detection in water environments.Currently,traditional physicochemical methods suffer from issues such as high energy consumption,secondary pollution,and low treatment efficiency.Therefore,there is an urgent need to develop new technologies and catalytic materials for the efficient treatment of emerging pollutants in water.Due to the different structural characteristics of pollutants,they possess different oxidation or reduction properties.Therefore,it is necessary to select appropriate reduction or oxidation reaction systems and enhance the role of reactive species to achieve efficient and rapid degradation of recalcitrant organic pollutants.Among them,transition metal single-atom/cluster materials with dispersed catalytic sites have demonstrated excellent removal performance for various pollutants in reduction/oxidation systems,providing a promising solution to the limitations of conventional treatment technologies.Based on these considerations,this study takes the molecular structural characteristics of pollutants as the starting point,targeting halogenated antibiotics and phenolic compounds as the model pollutants,and designs and develops highly catalytic active metal single-atom/cluster catalyst materials.By employing the interface confinement strategy,transition metal single-atom catalysts were prepared to enhance the generation of key reductive hydrogen species(H*)during electrochemical reduction,enabling efficient dechlorination conversion of aromatic halogenated antibiotic chloramphenicol(CAP).Through the combination of biologically enriched and chemically activated methods,transition metal cluster catalysts were synthesized to activate persulfate advanced oxidation systems,achieving rapid degradation and removal of phenolic endocrine disruptor bisphenol A(BPA).The developed transition metal single-atom/cluster catalysts provide a new research direction for the targeted design of efficient catalysts for the removal of halogenated antibiotics and phenolic pollutants.The main research content and results of this study are as follows:1.To address the challenge of the difficult dechlorination conversion of strongly polarized C-Cl bonds in CAP,a interface confinement strategy was employed to obtain silicon-based anchored copper single-atom catalyst material(Cu-SiOx)by sacrificial thermal decomposition of a two-dimensional nitrogen-carbon template.The Cu-SiOx catalyst was then applied in the electrochemical reduction dechlorination process of chloramphenicol(CAP).Under optimal reaction conditions,CAP could be completely converted within 3 hours,with a chloride ion removal rate reaching 98%.The firstorder reaction rate constant was determined to be 1.621 h-1,which is 8.6 times higher than that of commercial Pd/C electrode.The efficient dechlorination of chloramphenicol(CAP)was achieved through the dominant hydrogen spillover effect,where highly dispersed single-atom Cu sites decomposed water to generate reductive atomic hydrogen(H*),which interacted with the silicon-based support,leading to the cleavage of the C-Cl bond.This study expands the application scope of transition metal single-atom catalysts in the field of environmental electrocatalytic remediation,highlighting the synergistic effect of the support and providing a new approach for the design and synthesis of materials for the control of halogenated pollutants.2.To address the lack of catalysts for the deep oxidation degradation of phenolic pollutants,a strategy combining biotic enrichment and chemical activation was adopted.The characteristic of microbial enrichment of metal ions was utilized to serve as an ideal precursor,followed by thermal decomposition to prepare surface-functionalized iron/nitrogen co-doped biochar catalyst(Fe-N-BC).The Fe-N-BC catalyst was combined with peroxydisulfate(PMS)to form the Fe-N-BC/PMS system,which achieved 100%efficient removal of bisphenol A(BPA)within 20 minutes and a high mineralization rate of 80%.The first-order kinetic constant for BPA degradation in the system was determined as k=0.2968 min-1.Additionally,Fe-N-BC maintained high catalytic performance over a wide pH range of 4.0-10.0.The quenching of free radicals and electron paramagnetic resonance experiments confirmed that the main active species in the reaction was singlet oxygen(1O2),rather than free radicals.This work provides a novel method for synthesizing metal-nitrogen-doped carbon materials based on microbial biomass,thereby expanding the application scope of biomass in the field of environmental catalysis.