Study And Application Of Functionalized Materials In The Extraction And Adsorption Of Pesticides And Antibiotics Pollutants

Pesticides and antibiotics are two types of environmental organic pollutants.Most pesticides are highly toxic and can cause acute or chronic poisoning to humans or animals.And antibiotics,including sulfonamide antibiotics,fluoroquinolone antibiotics and macrolide antibiotics,enter the environment and lead to the drug resistance of bacteria.Both of them have been frequently found in the environment,posing a serious threat to human beings and the ecological environment.Due to their low concentration and the complexicity of sample matrix,it is difficult to directly analyze them with high-precision instruments.Thus,the pretreatment procedures are usually required for extracting the target pollutants in real samples,and through which the pressure on existing detection systems could be reduced and the sensitivity and accuracy of the proposed methods could be further improved.Based on functionalized ionic liquids（ILs）and metal-organic frameworks（MOFs）,a series of effective microextraction technologies were developed to achieve the extraction and analysis of pesticides or antibiotics in environmental samples.The detail contents of this work are as followed:（1）Based on the aromatic ring and phosphate structure of organophosphorus pesticides（OPs）,four functionalized imidazole ionic liquids were synthesized by modifying alkyl-,hydroxyl-and ester-functionalized branches.They were all used as extractants in dispersive liquid-liquid microextraction for extracting and enriching OPs.H¹NMR characterization was used to explore the interaction mechanism between ILs and OPs.Due to the electron-withdrawing carbonyl group of the ester branch,the strongestπ-πinteraction force exhibited between the ester-functional IL（[Mim CH₂CO-OCH₃][NTf₂]）and OPs.Compared with alkyl-and hydroxyl-functional ILs,it exhibited the best extraction and enrichment efficiency.Combined with high performance liquid chromatography,a fast,sensitive and accurate method for detecting five OPs was established based on[Mim CH₂COOCH₃][NTf₂].Under the optimal extraction conditions,the developed method was successfully applied to the extraction and analysis of OPs in environmental water samples with high enrichment factors（more than 440）and low detection limits(0.7-2.7μg L^-1).The recoveries of environmental water samples were in the range of 96.3-114.4%with RSDs of 0.7-5.0%.（2）Consedering the potential interaction forces,active adsorption sites and contact area,two types of typical MOFs,nitrogen-containing heterocyclic MOFs and organic carboxylic acid MOFs,were selected.Four functionalized MOFs,including ZIF-8,Cu（BTC）,Ui O-66 and Ui O-66-NH₂,were successfully prepared and used as adsorbents in dispersive micro-solid phase extraction for the enrichment of macrolide antibiotics（MACs）.The interaction forces between MOFs and MACs were also discussed by using Infrared Spectrum and Zeta Potentials.The results showed a stronger hydrogen bonding interaction and electrostatic interaction existed between ZIF-8 and MACs.Combined with HPLC-DAD,a sensitive and efficient method was developed for the detection of MACs in landfill leachate based on ZIF-8.The detection limits were 1.7-3.7μg L^-1 with the enrichment factors of 430-500.The recoveries of landfill leachate samples were in the range of 83.3-107.9%with RSDs of 3.3-9.2%.（3）By supporting functionalized ILs into the water-stable Zr-MOFs,novel ILs@Zr-MOFs nanocomposites were synthesized for the pretreatment of sulfonamide antibiotics（SAs）.The results indicated that[H₂Nmim][NTf₂]@Ui O-66-Br exhibited the best performance because of its multiple interactions between adsorbent and SAs including electrostatic interaction,hydrogen bonding interaction andπ-πinteraction.The adsorption isotherm and kinetic experiments demonstrated that the adsorption process followed pseudo-second-order kinetic model and Langmuir isotherm model.[H₂Nmim][NTf₂]@Ui O-66-Br showed good selectivity for SAs with maximum adsorption capacity of 352.1?mg?g^-1.After optimization,the developed dispersive micro-solid phase extraction-high performance liquid chromatography was successfully applied to the analysis of SAs in environmental water.The detection limits of seven SAs were lower than 0.03μg L^-1 with recoveries between 91.0%and 109.4%.（4）Polydopamine-functionalized Fe₃O₄ was introduced to construct a core-shell structure via layer-by-layer modification,and positively charged Fe₃O₄@Zr-MOFs were successfully obtained.Then,the hydrophobic carboxyl functionalized ionic liquid（IL-COOH）was encapsulated into the prepared Fe₃O₄@Zr-MOFs,and the novel water-stable IL-COOH/Fe₃O₄@Zr-MOFs were prepared.The composites were subsequently employed for the adsorption and enrichment of fluoroquinolone antibiotics（FQs）in environmental water.The adsorption isotherm and kinetic experiments demonstrated that the adsorption process followed pseudo-second-order kinetic model and Langmuir isotherm model.Among them,IL-COOH/Fe₃O₄@Ui O-67-bpydc showed the best adsorption performance,with maximum adsorption capacity of 438.5?mg?g^-1.Combined with HPLC-DAD,a fast,sensitive and efficient method for extraction and analysis of seven FQs in environmental water was established based on IL-COOH/Fe3O4@Ui O-67-bpydc.The recoveries of environmental water were ranging from 90.0 to 110.0%with the detection limits lower than 0.02μg L^-1.