| The metal organic framework materials are a nanometer porous material composed by organic ligand with inorganic clusters.They exhibit high specific surface area,versatile structure,tunable pore size and easy functionalization.These properties make them suitable as filler of the membrane for high performance mixed matrix membranes.In recent years,mixed matrix membranes based on metal-organic framework materials have attracted extensive attention of researchers due to their excellent properties.Most of MOFs membranes are currently used in the gas separation.There are several applications of MOFs membrance in the environmental field.Thus,in order to expand relevant research,our group applied MOFs membrance to the enrichment and the removal pesticide pollutants in this work.Because of its low concentration in environmental water samples,neonicotinoid insecticides need to be enriched before analysis.Adsorbent materials for sample pretreatment are the crucial factor to improve enrichment efficiency.On the other hand,2,4-dichlorophenoxyacetic acid has become one of the most used phenoxy acid herbicides.The existence of 2,4-dichlorophenoxyacetic acid in water exhibits a potential threat to human health.The research about adsorption materials for remove 2,4-dichlorophenoxyacetic acid is significante for environment manage.In this paper,a novel metal-organic framework mixed matrix membrane was prepared,which was applied to the enrichment of neonicotinoid insecticides in water and the removal of 2,4-dichlorophenoxyacetic acid in water.The following work was carried out:?1?MIL-53?Al?and MIL-53?Al?-PVDF MMM were prepared and were characterized by X-ray diffractometry,scanning electron microscopy and Fourier transform infrared spectrometer.The MOFs mixed matrix membranes were used as adsorbents for enrichment of four neonicotinoid insecticides in water and combined with high performance liquid chromatography for determination.The factors affecting the adsorption and the elution efficiency of the membrane were investigated.The linearity and the practicability in real water samples were excellent.The linear range of nitenpyram,imidacloprid,acetamiprid and thiacloprid were 0.30-15.00 ?g·L-1,0.04-15.00 ?g·L-1 and 0.05-15.00 ?g·L-1,respectively.The limits of detectionand and limits of quantitation of the method were 0.013-0.064 ?g·L-1 and 0.038-0.190 ?g·L-1,respectively.The intra-day precision?n=6?and inter-day precision?n=6?of the method were 3.07%-12.78% and 3.43%-13.12%,respectively.The method was applied to the detection of neonicotinoid insecticides in laboratory tap water,Qingdao Bohai Bay seawater and Qingdao reservoir surface water.The recoveries of spiked samples were 72.5%-117.98%.The MIL-53-PVDF MMM can be reused for 14 cycles.The method is reliable and accurate,and it possess high sensitivity and good reubility.?2?NH2-MIL-101?Fe?and NH2-MIL-101?Fe?-PVDF MMM were prepared and characterized.The factors affecting the removal efficiency of NH2-MIL-101?Fe?-PVDF MMM towards 2,4-dichlorophenoxyacetic acid in water were optimized,including the type of membrane,the dosage of MOFs,the p H and salinity of water samples,the adsorption time and the initial concentration.Under the optimal adsorption conditions,the process of adsorption reached equilibrium within 3 hours,which is consistent with the pseudo-second-order kinetic model;The maximum adsorption capacity of NH2-MIL-101?Fe?-PVDF MMM to 2,4-dichlorophenoxyacetic acid in water was 344.83 mg·g-1,which was consistent with the Langmuir adsorption isotherm model.The adsorption mechanism is the combination of electrostatic interactions and ?-? conjugate.Compared with traditional adsorbents,MOFs mixed matrix membranes exhibted various advantages including rapid adsorption process and high adsorption capacity. |
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