Study On Phenolic Pollutants In Water Based On Magnetic Nanoparticles Solid Phase Extraction Technology

Because that Phenolic contaminants are significant chemical materials,they are common pollutants in many industrial wastewater,causing serious pollution and ecological burden on natural environment and ecological environment.Alkylphenols and bisphenol pollutants are typical representatives of phenolic endocrine disruptors,which can produce triple effects on organisms and have cumulative effects on food chains.Even the intake of trace levels of phenolic pollutants will cause potential harm to human beings.Therefore,it is necessary to develop a simple,rapid and sensitive method for monitoring phenolic pollutants in water environment.However,in the actual natural water environment,alkyl phenols and bisphenol pollutants are very low,often at trace levels,and the water environment matrix is complex,which has serious interference on the direct detection results.It is necessary to develop new pretreatment methods to separate and enrich them before detection.The development of nanomaterial science has made magnetic nanoparticles brilliant in various fields.In this paper,based on the modification technology of magnetic nanoparticles,the optimal modification conditions were studied,and two kinds of magnetic nanoparticles with different properties were prepared and synthesized.Based on this,two new MSPE-HPLC methods for the detection of five phenolic pollutants in water were established.In the first chapter,it mainly summarizes the harm and current pollution situation of phenolic pollutants,and summarizes the instrument detection methods and common pretreatment methods of phenolic pollutants.The magnetic solid phase extraction technology and the modification of magnetic nanoparticles were introduced,and the background and content of this study were summarized.In the second chapter,with hexadecylphosphate acid as the modifier,the optimal modification dose of Fe₃O₄@PAC₁₆ nanoparticles modified by hexadecylphosphate acid was studied by theoretical calculation of its standard modification dosage and combined with characterization methods,and the modified Fe₃O₄@PAC₁₆ nanoparticles were successfully prepared.The modified Fe₃O₄ nanoparticles have superhydrophobicity acid,and the shape and size are relatively uniform.The particle size is between 16.6 nm and 35.8 nm,and the thickness of cetylphosphonic acid coating film is about 5～6 nm.The results of the Fourier transform infrared spectroscopy,the morphology analysis,the EDS spectrum analysis,and the thermal gravimetric analysis showed that the modification was successful.A new MSPE-HPLC method for the determination of five phenolic pollutants（Bisphenol A,Bisphenol B,Bisphenol AF,4-t-octylphenol,and nonylphenol）in environmental water samples was established using Fe₃O₄@PAC₁₆ nanoparticles modified successfully in the second chapter as magnetic solid phase adsorbent.By introducing the process of activating the stationary phase in the traditional SPE operation,the problems of difficult operation and poor reproducibility caused by poor dispersion of magnetic solid phase extraction adsorbent in water were solved.The optimal conditions of MSPE were determined by optimizing the amount of adsorbent,solution p H,extraction time and elution conditions:eluent type,volume,elution time.Under the optimal conditions,the reusability of magnetic nanoparticles was investigated.The results showed that Fe₃O₄@PAC₁₆ magnetic nanoparticles were stable in modification and could be reused for more than 10times.It was successfully applied to the detection and analysis of actual environmental water samples with satisfactory results（BPA,71.33%;BPB,87.58%;BPAF,94.82%;4-t-OP,95.07%;4-NP,95.41%）.In chapter 3,Fe₃O₄@PAC₁₆@PEG magnetic nanoparticles were prepared by modification,and based on this,it was established that another new MSPE-HPLC technique for the determination of five phenolic pollutants in environmental aqueous samples.By comparing different types of amphiphilic modifiers,PEG-6000 was finally selected as the modifier and the optimal grafting concentration was 0.3%.The new magnetic nano-material Fe₃O₄@PAC₁₆@PEG has a relatively suitable affinity/hydrophobicity,which is used as an adsorbent to establish the detection method of MSPE-HPLC,determine the optimal experimental conditions,and realize the simultaneous detection of BPA,BPB,BPAF,4-t-OP and 4-NP in actual water samples.With the perfect experimental conditions,the five phenolic contaminants showed good linearity in the concentration range studied with the linearly dependent coefficient（r）above 0.9993,and the LOD were 0.031～0.191μg/L,which met the requirements of actual sample detection.The precision was good（RSD within and between days were less than 4.55%,n=6）,The extraction rates were above 90.5%,and the recoveries of spiked water samples were at 92.9%～115%.The results met the requirements of analytical chemistry.