Study On Preparation And Application Of Atrazine Magnetic Molecularly Imprinted Materials

Atrazine is one kind of triazine herbicides.It can be used for the control of many annual grasses and broadleaf weeds,and it is widely used in agricultural production.In general,the trace atrazine is toxic to human and live stock.But the long-term's intake of high concentrations of atrazine can cause human heart and liver's damage.Therefore,the main countries in the world all seted a safety limit for atrazine in the drinking water.The experiment magnetic adsorbent with specific discriminating ability for atrazine was prepared under the action of heating by using molecular imprinting?MIT?relevant technology and method;in the method,Fe₃O₄ magnetic nanoparticles,atrazine,methacrylic acid?MAA?,ethylene dimethacrylate?EDGMA?,azobisisobutyronitrile?AIBN?were respectively used as carrier,template molecular,functional monomer,crosslinking agent and initiator.The adsorption material under the action of an external magnetic field can achieve rapid solid-liquid separation,selective adsorption,repeated use,etc.The method can avoid the traditional extraction process of reagent consumption,and provide a new idea for the detection of trace Atrazine.In the preparation of magnetic Fe₃O₄ nano materials,the molar ratio of FeSO4·7H2O and FeCl3·6H2O was 1:2.Tetraethyl orthosilicate?TEOS?dosage shouldnot be too little in coating SiO₂ protective layer on magnetic Fe₃O₄ nano material,lest Fe₃O₄ nanoparticles had exposed parts;in modifying Fe₃O₄@SiO₂,amount of KH-570 and Fe₃O₄@SiO₂ material was 2:1.In the process of preparing atrazine magnetic molecularly imprinted materials,molecular template,function monomer and crosslinking agent had a suitable proportion,and generally speaking,the best ratio of three materials was 1:4:20.After the atrazine magnetic adsorbent was prepared,a series of experiments such as the isothermal adsorption experiments,selective adsorption test and the factors influencing adsorption performance were designed for analying performance of atrazine magnetic adsorption in this paper.The results showed that within 0.5 h,adsorption agent's adsorption for atrazine belonged to fast adsorption stage,the time 2 h adsorption basically completed,the time 4 h adsorption reached saturation;at-MMIPs' adsorption for atrazine fit pseudo first order reaction mechanism and physical adsorption was the limited step,playing a leading role in the absorbing process;under the condition of isothermal adsorption,Freundlich isotherm correlation coefficient was higher than Langmuir isotherm,and the Freundlich adsorption isotherm model could be used to describe the adsorption process;adsorption sites of two different speed existed in the At-MMIPS,adsorption site type of high adsorption efficiency was single molecule layer adsorption;adsorption effectfor adsorbent of the same or similar substances structure of the template molecule was better.In this paper,the factors affecting the adsorption of At-MMIPS were analyzed.Experiments showed that under neutral to alkaline conditions,the adsorption effect was better;the adsorption reaction was exothermic,and low temperature was favorable to the adsorption;under the given experimental conditions,the adsorption capacity for atrazine increased with increasing dosage,there existed an optimal dosage.Finally,in the paper the orthogonal experiment was designed and the optimal adsorption combination of temperature,pH,dosage was analyzed and studied.For verifying the feasibility of material's using in actual sample pretreatment process,taking some water samples from a reservoir water,and a set of lower concentrations of atrazine solution were prepared.The concentration of the solution was near the minimum detection limit near of the high effective liquid phase chromatograph.so first of all,water samples should be the enriched via atrazine molecularly imprinted materials.After measuring the concentration of enriching atrazine samples,initial concentration of atrazine in water samples could be calculated.It was found that the enrichment and recovery rate of the atrazine magnetic adsorbent for trace elements in water was around 90%.The value of the atrazine magnetic adsorbent was slightly lower than the national standard method;but The advantage of the former was that the operation was simple,and saved drugs.Therefore,it was feasible that atrazine magnetic adsorbent made by molecular imprinting technique was used for detecting the trace Atrazine in water.