Preparation And Properties Research On Zn(?) Imprinted Monolithic Column

In recent years,ion imprinting technology has become a research hotspot and is used in various fields.Among them,the research on the treatment of heavy metals in the environment with ion imprinting technology has developed rapidly.In general,environmental samples are more complex,and separating a single substance from it is technically challenging.Ion imprinting technology provides new ideas for the separation and removal of trace components,because the preparation methods of ion-imprinted polymers are various and most of them are easy to operate.Among them,the ion imprinted monolithic column has advantages in sample pretreatment,and this technology has been widely used in the chemical and biological fields for the separation of structurally similar substances.In terms of environmental protection,because the imprinted polymer is capable of enriching small amounts of substances in environmental samples and because it has specific selective adsorption properties,it has also been developed new technical fields for the recovery and reuse of some specific and rare substances.In this dissertation,zinc ion imprinted monolithic columns were synthesized on the column(25mm×4.6mm)by in-situ polymerization,and the porogen systems needed to prepare the polymers were optimized,and the synthesis of various porogens was examined.What is more,the performance of Zinc ion imprinted monolithic columns was evaluated.(1)Eight different porogenic systems were initially evaluated: Zn(?)as a template,?-methacrylic acid as a functional monomer,methanol as a solvent,and ethylene glycol dimethacrylate as a cross-linking agent.Azobisisobutyronitrile as initiator,porogenic system: cyclohexanol/dodecanol;cyclohexanol/dodecanol/toluene;toluene/isooctane;tetrahydrofuran/trichloromethane;dimethylformamide;Dimethylformamide/dodecanol;tetrahydrofuran/isooctane;tetrahydrofuran/isooctane/toluene;eight different zinc ion imprinted monolithic columns were synthesized and their adsorption properties were measured.The experimental results show that when the tetrahydrofuran/iso-octane,tetrahydrofuran/isooctane/toluene,dodecanol/iso-octane/toluene are the porogens,the integrated column enrichment times are larger.(2)Zn(?)as template,?-methacrylic acid as functional monomer,methanol as solvent,ethylene glycol dimethacrylate as cross-linking agent,azobisisobutyronitrile as initiator,tetrahydrofuran/ Iso-octane/toluene is a porogen,and a synthetic zinc ion imprinted monolithic column was used.The effect of elution flow rate on the elution effect was examined.The optimum elution volume was measured at the same time,and the concentration of different solutions was measured at the same temperature.Finally,the standard curve of zinc ion was measured by high performance liquid chromatography.The curve was linear.The experimental results show that: the best elution flow rate in this experiment is 0.25mL/min;the optimal elution volume is 8mL;the best concentration of zinc ion is 3mmol/L.(3)Using tetrahydrofuran/iso-octane,tetrahydrofuran/iso-octane/toluene,dodecanol/cyclohexanol/toluene as porogens respectively,the uniform design experimentation was conducted to determine the maximum of each pore system within a certain volume range.The results showed that when the volumes of tetrahydrofuran and isooctane were 0.7 mL and 0.9 mL respectively,the zinc ion imprinted monolithic column had the highest adsorption capacity of zinc ion,and the adsorption specific gravity reached 7.0379 mg/g;when tetrahydrofuran,isooctane,toluene volume When 1.0 mL,0.9 mL,and 0.1 mL were used,the total amount of zinc ion imprinted monolithic columns synthesized was the largest,and the specific gravity was 9.5270 mg/g;when the volumes of cyclohexanol,dodecanol,and toluene were 1.2 mL,1.2 respectively.In the case of mL and 0.8 mL,the adsorption capacity of the synthesized zinc ion imprinted monolithic column was the largest,and the adsorption specific gravity was 10.9162 mg/g.Zinc ion imprinted monolithic columns were synthesized using the optimal volume ratio of each pore system,and their selective adsorption performance was tested.The zinc,cadmium,lead,and copper mixed metal solutions each having a concentration of 3 mmol/L were uniformly flown through the monolith and the content of each metal ion was measured after elution.The results show that the adsorption capacity of copper on three monolithic columns is relatively low,even not detected,but the three monolithic columns have different degrees of adsorption of lead and cadmium ions.It was found that tetrahydrofuran/iso-octane/toluene was more suitable as a porogen because the corresponding zinc ion imprinted monolithic column had higher adsorption performance and better selectivity.