Construction Of Perylene Diimide-based Functional Material Systems And Their Application In Removal Of Organic Hazards,antibiotic Resistance Bacteria And Antibiotic Resistant Genes

In the backdrop of focusing on food safety and human health,the problem of water pollution has attracted global attention.Due to the continuous discharge of wastewater from the aquaculture,industrial and medical industries,which containing organic hazards such as phenols and antibiotics into the ecosystem and most of these organic hazards are biotoxic,environmentally persistent and bioaccumulative,posing a serious threat to the ecosystem.Besides,in addition to chemical pollution,antibiotic hazards remaining in the environment for a long time can also cause selective pressure on microorganisms in the environment and induce biological contaminants such as antibiotic resistant bacteria（ARB）and antibiotic resistance genes（ARGs）.These chemical and biological food safety hazards accumulate in agricultural and livestock products,aquatic products and even drinking water through a range of channels and can enter the human body through the food chain,causing serious food safety problems.The strong oxidizing active species generated during the reaction of advanced oxidation technologies can rapidly decompose and mineralize pollutants in water into small molecules such as CO₂ and H₂O,while inactivating ARB and effectively controlling the horizontal transfer and spread of ARGs in the water environment.Thus,the advanced oxidation technologies have broad application prospects in water purification.Perylene diimide（PDI）organic materials and their derivatives are considered to be one of the best n-type organic semiconductors due to their excellent spectral responsiveness,electron affinity and structural modulation.In this paper,self-assembled PDI（SA-PDI）was used as the main photocatalyst to achieve effective removal of phenolic and antibiotic chemical pollutants as well as ARB and ARGs biological pollutants through two schemes:construction of Z-scheme heterojunction and construction of photocatalysis-self-Fenton system.1.A plasmonic Z-scheme Ag@Ag Cl/PDI photocatalyst was successfully synthesized by an in-situ deposition-photoreduction method.The morphological structure and photoelectric properties of Ag@Ag Cl/PDI composite were systematically investigated using various techniques.The degradation rates of optimum Ag@Ag Cl/PDI-3%towards phenol,bisphenol A,sulfadimethoxine and ofloxacin were approximately 5.7,4.0,3.2 and 10.0 times higher than those of SA-PDI,respectively.Meanwhile,Ag@Ag Cl/PDI-3%killed all sulfonamide ARB within 2 h and inactivated 99.6%of sulfonamide ARGs（sul1）within 8 h,while SA-PDI removed only 49.4%of ARB and 49.9%of sul1.Compared with SA-PDI,Ag@Ag Cl/PDI exhibited a more significant visible photocatalytic oxidation performance in eliminating organic hazards,ARBs and ARGs by the following mechanisms:（1）The loading of Ag@Ag Cl nanoparticles could improve the light absorption of SA-PDI through surface plasmon resonance effect and promote the photogenerated charge generation.（2）Ag nanoparticles as electron traps can effectively capture the photogenerated electrons in the conduction band of SA-PDI,while the Schottky barrier formed by Ag⁰ can promote the transfer of SPR-excited electrons from Ag to Ag Cl,further accelerating the charge separation and reducing the chance of composite photogenerated electron-hole pairs.（3）More reactive species（¹O₂,·O₂^-,h⁺and·OH）were generated during the reaction to improve the oxidation ability of the composites.2.GO/SA-PDI composite photocatalyst was successfully synthesized by low-temperature hydrothermal method and a photocatalysis-self-Fenton system synergistic system based on GO/SA-PDI and Fe³⁺was constructed.The morphological structure and photoelectric properties of the GO/SA-PDI composite photocatalysts were systematically investigated using various techniques.The photocatalytic activity of GO/SA-PDI（80%）for H₂O₂ production was4.1 times higher than that of SA-PDI.The performance of the photocatalysis-self-Fenton system based on GO/SA-PDI for the degradation of antibiotics and the removal of sulfonamide ARBs and ARGs was dramatically improved by the addition of Fe³⁺.Compared with SA-PDI photocatalysis system,GO/SA-PDI（80%）photocatalysis system and photocatalysis-self-Fenton system based on SA-PDI,the degradation activity of photocatalysis-self-Fenton system based on GO/SA-PDI（80%）for sulfamethoxazole was increased by 85.7,42.8 and 2.6 times,respectively.In addition,the photocatalysis-self-Fenton system based on GO/SA-PDI（80%）system achieved complete inactivation of sulfonamide ARBs within 15 min and removed 99.9%of sulfonamide ARGs（sul1）within 2 h,while the GO/SA-PDI（80%）photocatalysis system removed only 54.7%of ARB and 66.0%of sul1.Finally,the enhanced oxidation performance of the photocatalysis-self-Fenton system based on GO/SA-PDI was elucidated:（1）The introduction of GO could enhance the light absorption ability of the material and promote the generation of more quantity of photogenerated charges;（2）The two-dimensional nanosheet structure of GO could effectively prevent the aggregation of SA-PDI nanofibers,exposing more reactive sites on their surface and enhancing the adsorption ability of O₂ and hazardous materials.Thus,it could promote the participation of photogenerated charges in the reduction of O₂ to synthesize H₂O₂ and the oxidative removal of pollutants;（3）GO and SA-PDI were tightly bonded throughπ-πinteractions,which could trigger the electron delocalization effect and promote interlayer electron transfer,while the conductive carbon matrix of GO facilitated the acceleration of photogenerated charge migration at the interface,which in turn improved the photocatalytic H₂O₂ yield;（4）The added Fe³⁺consumed a large amount of photogenerated electrons for the reduction to Fe²⁺,which promoted the cyclic conversion of Fe³⁺/Fe²⁺,and then significantly improved the efficiency of the self-Fenton reaction of H₂O₂ produced in-situ by GO/SA-PDI with Fe²⁺to generate·OH.Meanwhile,it could inhibit the combination of photogenerated charges and improve the yield of photogenerated holes;（5）The photocatalysis-self-Fenton system based on GO/SA-PDI could produce more active species（h⁺,·OH,·O₂^-and¹O₂）to enhance the oxidation performance and mineralization efficiency of the synergistic reaction system,and ultimately exhibit better removal ability for antibiotics,ARB and ARGs.