Fabrication Of Functional Magnetic Materials And Their Adsorption Of Bisphenol Endocrine Disrupting Chemicals In Environmental Water And Food

Bisphenols compounds are widely used and have high yields and they are widely used in water environment and food.As endocrine disrupting chemicals(EDCs),even trace exposures can cause damage to human health,ecological risk and food safety.Therefore,the efficient removal of bisphenol pollutants in water is of great significance for sewage treatment and environmental water restoration.In environmental water samples and food samples,most of the bisphenol pollutants remain in trace amounts,and the matrix interference is serious.Therefore,the choice of sample pretreatment methods is directly related to the accuracy and effectiveness of the test results.In this regard,this paper aims at the difficulty in separation and collection of bisphenol pollutants and related adsorbents in the sample pretreatment process in the adsorption water environment,poor regeneration cycle,low adsorption capacity,single adsorption force,and trace extraction.Two noval functionalized magnetic composite materials with rich adsorption force,large adsorption capacity,convenient separation and collection,and fine regeneration cycle were prepared and used in sewage and wastewater treatment,enrichment and separation of trace residual bisphenol pollutants in environmental water samples and food samples,and the specific research content is as follows:(1)In view of the current adsorption and removal of bisphenol pollutants,there are problems such as difficulty in separation and collection,single adsorption force,poor regeneration cycle,low adsorption capacity,and single use.ferromagnetic ball(Fe₃O₄)was synthesized as the magnetic core,chitosan(CS),graphene oxide(GO)and?-cyclodextrin(?-CD)were used as functional monomers,and glutaraldehyde(50%)was used as the cross-linking agent,through cross-linking reaction and amidation reaction and multi-step preparation methods,developed a novel functional magnetic composite material,and named MCGC,through the study of the amount ratio of functional monomers(w/w/w),when the mass ratio of the three functional monomers is 1:1:5,the adsorption performance of MCGC was the strongest,and a series of characterization tests such as SEM,TEM,FTIR,XRD,EDS,BET,TGA and VSM were performed on MCGC,which showed that the morphology and crystal structure of MCGC were fine,The main functional monomers,such as CS,GO and?-CD,were successfully introduced.During the preparation process,Fe₃O₄ remained intact as the magnetic core crystal structure.The average specific surface area was 91.83 m²/g,the average pore diameter was 12.08 nm,and the magnetization was 16.2 emu/g,which can be separated and collected by an external magnetic field.With BPA and BPF as the adsorption research objects,the adsorption performance of MCGC was optimized and the adsorption experimental data was obtained under the optimal adsorption parameters,using a variety of adsorption models(adsorption isotherm model,kinetic model and thermodynamic model),fitting calculations are performed.The adsorption isotherm study shows that the adsorption process of MCGC is Redlich-Peterson type adsorption,and the maximum adsorption capacities for BPA and BPF are 326.8 mg/g and 328.3 mg/g,respectively;adsorption kinetics study It shows that the adsorption process follows a pseudo-second-order kinetic model;thermodynamic studies show that the adsorption process is an exothermic spontaneous process;the adsorption mechanism is analyzed by combining the fitting results,which shows that there are multiple adsorption sites on the MCGC surface,and the adsorption site distribution is multi-layer heterogeneous,its adsorption mechanism may be?-?attraction force,hydrophobic force,hydrogen bond force and electrostatic force and other forces of cooperative adsorption.After 5 cycles of adsorption,MCGC still has about 84.1%and 81%removal rates for BPA and BPF,and verified by real sewage samples,MCGC has certain practical application value.The above research results show that MCGC has the characteristics of rich adsorption force,large adsorption capacity,convenient separation and collection,and good regeneration cycle.It is a promising and efficient adsorbent,which provides a basis for sewage treatment and environmental water restoration.(2)In order to expand the use of MCGC adsorbent,MCGC is used as the extraction material in the pretreatment process,combined with high performance liquid chromatography fluorescence detector(HPLC-FLD)for detection,to establish a simultaneous determination analysis methods of four bisphenol pollutants in water environment and food of beverage.Through a series of optimization of extraction and elution conditions,the optimal pretreatment conditions were obtained,and the established method was tested under the optimal parameters for humic acid,glucose,fructose,sucrose and other interference factors.The results showed that the recovery rate was basically no effect.Evaluation of the established method under optimal pretreatment conditions showed that the method has a fine linear range,a lower detection limit and a limit of quantification,and the reproducibility is fine.Six kinds of environmental samples(river and lake water samples)and four kinds of food samples(plant protein beverages and juices)were blanked and added,Their recovery rate is satisfactory.Therefore,the above research results show that the established analysis method can well realize the trace residues of various bisphenol pollutants in water environment and food of beverage,and provide a new method for the analysis of trace residues of multiple bisphenol pollutants in water environment and food.(3)Combining the characteristics of mesoporous adsorbents,Fe₃O₄ is also used as the magnetic core,cetyltrimethylammonium bromide(CTAB)and tetraethoxysilane(TEOS)are used as functional monomers,and a simple etching method is used to develop a novel magnetic mesoporous composite material MMC,and used it for the first time to adsorb bisphenol pollutants in water.According to the test and analysis results of SEM,TEM,FTIR,XRD,Mapping,EDS,BET,TGA and VSM,it is confirmed that the surface of MMC has an obvious wormhole-like mesoporous structure.Both CTAB functional groups and Si-OH are successfully introduced.Fe₃O₄ is the crystal structure remained stable during the subsequent preparation process.According to the Mapping test results,the CTAB functional groups are uniformly distributed without agglomeration.The average specific surface area and average pore diameter are 148.6 m²/g and 2.9 nm,respectively.It also has a high magnetization intensity(65.3 emu/g).MMC can achieve rapid separation and collection by applying a magnetic field.After MMC adsorption performance optimization research,the best adsorption parameters are obtained,and the adsorption isotherm model,adsorption kinetic model and thermodynamic model are used to perform fitting calculations under the optimal adsorption conditions.The results show that the maximum adsorption capacity of MMC is208.3 mg/g.The adsorption process follows the Freundlich isotherm model and pseudo-second-order kinetic model.The adsorption process is an exothermic spontaneous process.The surface of MMC has multiple adsorption active sites,and the adsorption active sites are heterogeneously distributed,combined with related adsorption The model and the main functional groups on the surface of MMC,analyze the adsorption mechanism of MMC to bisphenol pollutants,which may be mainly hydrophobic,electrostatic and hydrogen bonding;after six adsorption-desorption cycles,the regeneration rate of MMC is 80.5%,and compared with tests results of FTIR,XRD and TEM show that the overall structure of MMC is relatively stable and the reproducibility is strong;and the results of MMC are verified by actual samples,and the results are satisfactory;the comparison between MMC and MCGC and other adsorbents shows that MMC has relatively high large specific surface area,higher magnetization,abundant adsorption force and larger adsorption capacity.In summary,MMC has fine application prospects,can efficiently remove bisphenol pollutants,and has the potential for sewage treatment and environmental water restoration.(4)Also use the developed MMC as the adsorbent in the sample pretreatment process,and use HPLC-FLD detection to establish an analytical method that can simultaneously determine the six kinds of bisphenol pollutants in the trace residues of the water environment and food,so as to realize the variety of MMC use.Through the system optimization of extraction and elution conditions,the optimal pretreatment conditions were obtained,and the established method was tested under the optimal conditions for interference factors such as humic acid,glucose,fructose,and sucrose.The results showed that the recovery rate was basically no influences.Through the methodological evaluation of the established method,the results show that the method has a fine linear relationship(R>0.997),a linear range,and a lower detection limit and the limit of quantification,and the recovery rate is satisfactory,and for two types of environmental samples(river and lake)and three types of food samples(milk,juice and carbonated Beverages),a total of seven actual samples were analyzed for blank and standard addition,and the recovery rate of standard addition is satisfactory.And after comparing with the previously established MSPE(MCGC)-HPLC-FLD method,the results show that the established MSPE(MMC)-HPLC-FLD method has the same detection limit and the recovery rate,the extraction speed of MCGC is faster.Therefore,this method can realize the analysis and detection of various bisphenol pollutants in environmental water samples and food samples of various types of complex matrices,and provide trace analysis method of other similar types of contaminants in complex matrix samples.