Study On Preparation Of MOFs Composite & Derivative Materials And Extraction Of Non-steroidal Drugs

Non-steroidal anti-inflammatory drugs（NSAIDs）are a class of effective anti-inflammatory,analgesic and antipyretic drugs,which have become an essential part of human survival.Especially in recent years,the demand and usage of NSAIDs have greatly increased.However,the side effects of NSAIDs cannot be ignored either.Studies have shown that prolonged exposure to low concentrations of various drugs,plants,animals,and naturally distributed bacteria will develop a wide range of drug resistance,thus falling into a situation of"no medicines available",or even promoted the emergence of"super virus".Therefore,there is an urgent need to establish an effective method for monitoring NSAIDs in environmental water.However,the concentration of the target molecule in the water sample is extremely low,and it is difficult to detect it directly with the instrument.Only by using effective sample pretreatment techniques and selecting appropriate sorbents can the effects of matrix and impurities be eliminated and the purpose of qualitative and quantitative analysis can be achieved.Metal-Organic Frameworks（MOFs）have the advantages of high specific surface area and porosity,adjustable structure and pore size,and post-processing modification.Therefore,they have been extensively studied in the field of analysis and separation.However,the water stability of pure MOFs is poor,which seriously affects their service life.Usually,MOFs are compounded with inorganic nanoparticles or special chemical treatments can effectively improve their water stability and at the same time increase their extraction performance.Based on the many advantages of MOFs materials,this thesis prepared MIL-101@TiO₂NTs and two MOFs derived materials,combined solid phase extraction（SPE）and magnetic solid phase extraction（MSPE）technology to study the extraction of NSAIDs in Yellow River water samples.This thesis is mainly composed of four parts,and finally it summarizes and prospects.Chapter 1.This chapter mainly introduces the application of MOFs composite materials or MOFs derived materials combined with SPE and MSPE in the field of analysis and separation.First,the characteristics and extraction methods of SPE and MSPE are comprehensively introduced.Secondly,the preparation method of MOFs is introduced in detail.Finally,the current applications of MOFs composite materials or MOFs derived materials in the field of analysis and separation are reviewed.Chapter 2.In this chapter,a new type of MIL-101@TiO₂ NTs composite material was prepared and used as a solid-phase sorbent to determine NSAIDs in environmental water samples with HPLC.The effects of elution solvent,p H,extraction speed,elution speed and sample volume on SPE were studied in detail.Compared with the original single material MIL-101 and TiO₂ NTs,the composite material has better extraction performance for NSAIDs.At the same time,it has a good linear range,lower detection limit and stable reusability.The main reason for this result is that the composite material takes into account all the forces between the two original materials and the target,includingπ-πconjugation,coordination and hydrogen bonding between MOFs and analytes,and the coordination effect of TiO₂ NTs with analyte and anion-πinteraction.In addition,the tubular structure of TiO₂ NTs provides sites for the formation of MOFs,making them more dispersible,exposing more adsorption sites,and improving extraction efficiency.Chapter 3.In order to further improve the adsorption site and force of MOFs,the core-shell ZIF-8@ZIF-67 material was successfully prepared by using ZIF-8 as the core.Subsequently,ZIF-8@ZIF-67 was converted into a hollow MOFs derivative（ZIFs@Zn S@CoS）composite material by chemical etching,and used as a solid-phase sorbent,combined with HPLC to determine NSAIDs in environmental water samples.After optimizing the extraction and desorption conditions,compared with ZIF-8 and ZIF-8@ZIF-67,the composite material shows better extraction performance for NSAIDs,and at the same time,it also obtains a good linear range and lower the detection limit and stable reusability.Compared with MIL-101@TiO₂NTs,the unsaturated coordination of the bimetal in this material increases the coordination effect between the material and the target.The special hollow structure can provide more adsorption sites and accelerate the adsorption equilibrium.In addition,Zn S and CoS materials can greatly enhance the stability of the hollow structure of ZIFs@Zn S@CoS materials,making composite materials have a longer service life.Chapter 4.MSPE can effectively overcome the unfavorable factors of the filler loading method in SPE technology due to its sorbent dispersibility,speed up the mass transfer speed,and improve the extraction efficiency.This work uses MIL-101 as the precursor to prepare the magnetic MOFs-derived material MD-350,and uses it as a magnetic solid-phase sorbent,combined with HPLC to determine the NSAIDs in environmental water samples.Compared with other MOFs derivative materials at other treatment temperatures,MD-350 retains more of theπ-πconjugation,hydrogen bonding and coordination between the MOFs material ligand and the analyte,as well as the spatial structure and characteristics of activated carbon.It also gives it a larger specific surface area,and at the same time the magnetic properties of the material are maximized.After optimizing a series of extraction conditions,the magnetic material obtained a wider linear range,larger extraction volume and shorter extraction time than the previous two materials.These advantages make the prepared MD-350 material used for fast,accurate and long-lived trace analysis of NSAIDs in complex matrices.In short,based on MOFs materials,this article has developed three types of MOFs@TiO₂ NTs,ZIFs@Zn S@CoS,MD-350,three types of MOFs composite and derivative material sorbents,and explored their properties and their effects on NSAIDs in SPE（MSPE）.The extraction performance enriches the adsorption mechanism of MOFs composite and derivative materials（multiple adsorption sites,good porosity,diversified functions,etc.）,and supplements the theoretical basis for the development of sorbents for MOFs materials.The application played a certain role in promoting.