微波辅助合成反相镉离子印迹聚合物及其对废水中镉的吸附和固相萃取

发布时间：2018-06-08 05:01

本文选题：微波辅助 + 反相乳液聚合　；参考：《太原理工大学》2017年硕士论文

【摘要】：镉是一种具有致癌、致畸的有毒重金属,可以对环境和人体造成严重的危害。离子印迹聚合物具有高选择性、良好的稳定性、良好的循环使用能力及应用范围广等优点,作为一种新型的吸附材料可以被用来分离和去除水中的重金属离子。制备印迹聚合物过程中采用微波辅助法可以缩短聚合时间,加快反应的进行。本文通过微波辅助两种聚合方法、选择不同的功能单体分别制备了两种不同的镉离子印迹聚合物并用于水中镉离子的吸附和固相萃取。以β-环糊精和丙烯酰胺作为功能单体、环氧氯丙烷作为交联剂、过硫酸铵作为引发剂通过微波辅助反相乳液聚合法制备镉离子印迹聚合物(IEIIP)。用SEM、FTIR和TG对IEIIP进行结构表征。研究了Cd(Ⅱ)的初始浓度、溶液p H值、反应温度、时间和竞争离子对IEIIP吸附量的影响。在最佳吸附条件下,IEIIP的吸附量达到107mg/g。非印迹聚合物的吸附量比印迹聚合物的吸附量小52.4mg/g。选择性研究表明,IEIIP对Cd~(2+)/Pb~(2+)、Cd~(2+)/Cu~(2+)和Cd~(2+)/Zn~(2+)的选择性系数分别为2.7624、3.8154和1.1500。而IENIP的选择性系数k分别为0.4521、0.5024和0.3747,说明IEIIP对溶液中的镉离子有较好的选择性。此外,用准一级、准二级动力学模型和颗粒内扩散模型描述IEIIP对镉的吸附动力学行为。结果表明准二级动力学方程能很好地描述IEIIP的吸附行为。Langmuir等温线模型符合IEIIP对溶液中Cd(Ⅱ)的吸附行为,表明吸附过程是以单层吸附为主。Scatchard分析得到的离解常数KD和最大表观结合能力Qmax分别为72.99mg/L和130mg/g,说明IEIIP对Cd(Ⅱ)的吸附位点是等价的。热力学参数ΔG00、ΔH00和ΔS00表明吸附过程是自发的、吸热的。采用IEIIP作为固相萃取吸附剂,研究了洗脱液浓度、Cd(Ⅱ)初始浓度、p H值和竞争离子对萃取效率的影响,并对IEIIP固相萃取柱的重复性和精密度进行检验。结果表明,洗脱液甲醇:乙酸为7:1时富集效果最好,Cd(Ⅱ)的浓度为10μg/L,溶液p H值为7时萃取效率最高。IEIIP固相萃取柱在重复使用5次后萃取效率在70%以上。IEIIP固相萃取柱对离子混合溶液中Cd(Ⅱ)的萃取效率要高于其他竞争离子,这是因为IEIIP具有良好的选择性。通过IEIIP固相萃取柱平行分析11次标准溶液来检验方法的精密度,相对标准偏差(RSD)为2.699%,检出限3σ为0.8094μg/L(n=11)。对实际废水样本中Cd(Ⅱ)的加标回收率在93.58%到101%之间。以席夫碱作为功能单体、EGDMA作为交联剂、AIBN作为引发剂通过微波辅助反相乳液-悬浮聚合制备了镉离子印迹聚合物(IESIIP)。采用SEM、FTIR对IESIIP进行结构表征。通过静态吸附实验和竞争吸附实验研究IESIIP对溶液中Cd(Ⅱ)的吸附能力,研究了不同的影响因素包括Cd(Ⅱ)的初始浓度、溶液p H值、温度、时间和竞争离子对IESIIP吸附效果的影响。在最佳吸附条件下,IESIIP的吸附量为179.04mg/g。Cd~(2+)/Pb~(2+)、Cd~(2+)/Cu~(2+)和Cd~(2+)/Zn~(2+)的相对选择性系数k'分别为2.1061、4.7306和4.5602表明IESIIP对镉的选择性要远大于IESNIP的选择性。IESIIP的吸附过程符合准二级动力学方程和Langmuir等温线模型(R20.99)。Scatchard模型计算得到IESIIP上两类结合位点的离解常数KD分别为16.89mg/L和39.84mg/L,最大表观吸附量Qmax分别为105.15mg/g和171.84mg/g。热力学参数表明吸附可以自发进行,并且是吸热过程。IESIIP作为固相萃取柱填料时研究洗脱剂浓度、Cd(Ⅱ)初始浓度、p H值和竞争离子对萃取效率的影响。并评价固相萃取柱的稳定性和精密度。结果表明最佳的洗脱条件为0.5mol/L盐酸,萃取效率随着Cd(Ⅱ)浓度的增大而减小,最佳的p H条件为7。该固相萃取柱经5次重复使用后萃取效率仅仅下降了9.9%,说明该萃取柱具有良好的重复使用能力。将含有竞争离子的溶液通过固相萃取柱时,IESIIP对Cd(Ⅱ)的萃取效率明显高于其他的竞争离子。该方法的相对标准偏差(RSD)为2.699%,检出限3σ为0.288μg/L(n=11)。在最佳固相萃取条件下,对实际废水样本中Cd(Ⅱ)的加标回收率为95.22%-104%。
[Abstract]:Cadmium is a toxic heavy metal which is carcinogenic and teratogenic. It can cause serious harm to the environment and human body. The ion imprinted polymer has the advantages of high selectivity, good stability, good recycling ability and wide application. As a new type of adsorption material, it can be used to separate and remove heavy metal ions in water. In the process of preparing imprinted polymer, microwave assisted method can shorten the polymerization time and accelerate the reaction. In this paper, two different cadmium ion imprinted polymers were prepared by microwave assisted two polymerization methods and used to adsorb cadmium ion and solid phase extraction in water. Amine is used as a functional monomer, epichlorohydrin as a crosslinker and ammonium persulfate as an initiator to prepare cadmium ion imprinted polymer (IEIIP) by microwave assisted reverse phase emulsion polymerization. The structure of IEIIP is characterized by SEM, FTIR and TG. The initial concentration of Cd (II), the solution P H value, reaction temperature, time and competitive ions to IEIIP adsorption amount are studied. Under the optimal adsorption conditions, the adsorption capacity of IEIIP is less than that of the imprinted polymer, which is smaller than that of the imprinted polymer. The selective coefficient of the IEIIP to Cd~ (2+) /Pb~ (2+), Cd~ (2+) /Cu~ (2+) and IEIIP is respectively the selectivity coefficient respectively. For 0.4521,0.5024 and 0.3747, it is shown that IEIIP has good selectivity for cadmium ions in the solution. In addition, the adsorption kinetics of cadmium by IEIIP is described by quasi first order, quasi two kinetics model and internal particle diffusion model. The results show that the quasi two order kinetic equation can describe the adsorption behavior of IEIIP with.Langmuir isotherm model conforming to IE well. The adsorption behavior of IIP on Cd (II) in the solution shows that the adsorption process is KD and the maximum apparent binding capacity Qmax of the single layer adsorption.Scatchard analysis 72.99mg/L and 130mg/g respectively. It shows that the adsorption site of IEIIP to Cd (II) is equivalent. The thermodynamic parameter delta G00, Delta H00 and Delta S00 indicate that the adsorption process is spontaneous and endothermic. Using IEIIP as solid phase extraction adsorbent, the effect of eluent concentration, initial concentration of Cd (II), P H value and competitive ion on the extraction efficiency were studied, and the repeatability and precision of IEIIP solid phase extraction column were tested. The results showed that the enrichment effect was best when the eluent was methanol: acetic acid was 7:1, the concentration of Cd (II) was 10 u g/L, and the P H value of the solution. The extraction efficiency of the.IEIIP solid extraction column at 7 time is highest. The extraction efficiency of Cd (II) in the mixed solution of.IEIIP solid extraction column is higher than that of other competitive ions in the mixed solution of 70%.IEIIP after repeated use. This is due to the good selectivity of the IEIIP solid extraction column. The method of parallel analysis of the IEIIP solid phase extraction column for the test of the standard solution The precision, the relative standard deviation (RSD) was 2.699%, the detection limit was 3 Sigma 0.8094 g/L (n=11). The recovery rate of Cd (II) in the actual wastewater samples was between 93.58% and 101%. The Schiff base was used as a functional monomer, EGDMA as a crosslinker, and AIBN was used as a initiator to prepare the cadmium imprinted polymer by microwave assisted reverse phase emulsion suspension polymerization. IESIIP). The structure of IESIIP was characterized by SEM and FTIR. The adsorption capacity of Cd (II) in the solution by IESIIP was studied by static adsorption and competitive adsorption. The influence factors including the initial concentration of Cd (II), the H value of P, temperature, time and the effect of competing ions on the adsorption of IESIIP were studied. Under the optimal adsorption conditions, I The adsorption capacity of ESIIP is 179.04mg/g.Cd~ (2+) /Pb~ (2+), Cd~ (2+) /Cu~ (2+) and Cd~ (2+) /Zn~. The dissociation constant KD of the two binding sites on the IESIIP is 16.89mg/L and 39.84mg/L respectively. The maximum apparent adsorption capacity Qmax is 105.15mg/g and 171.84mg/g. thermodynamics parameters show that adsorption can be carried out spontaneously, and it is the concentration of eluent, Cd (II) initial concentration and P H value when.IESIIP is used as solid phase extraction column for the endothermic process. And the influence of the competitive ion on the extraction efficiency and evaluation of the stability and precision of the solid phase extraction column. The results show that the best elution condition is 0.5mol/L hydrochloric acid, the extraction efficiency decreases with the increase of Cd (II) concentration, the best p H condition is 7., the extraction efficiency of the solid phase extraction column is only 9.9% after the extraction, indicating that the extraction efficiency is only 9.9%. The extraction efficiency of IESIIP for Cd (II) was significantly higher than that of other competitive ions. The relative standard deviation (RSD) of the method was 2.699% and the detection limit was 3 Sigma 0.288 g/L (n=11). Under the optimum solid-phase extraction conditions, Cd (II) in the actual wastewater samples. The recovery rate of the added standard is 95.22%-104%.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631.3;X703

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