三维有序大孔重金属吸附剂制备及其应用

发布时间：2019-01-14 14:50

【摘要】：如今,重金属污染已经成为环境污染的主要问题之一,它给人类健康带来极大的危害,如引发肾病、肝病、呼吸道疾病和皮肤癌等,治理重金属污染迫在眉睫,重金属吸附剂越来越受到科学家们的关注。本论文制备了两种三维有序大孔重金属吸附剂,主要研究内容如下:1.通过胶晶模板法制备了孔径为500nm三维有序交联聚苯乙烯孔材料(3DOM CLPS),在三维有序交联聚苯乙烯上通过活性聚合的方法引入聚甲基丙烯酸二甲氨基乙酯链段(PDMAEMA),和其它报导的吸附剂相比,三维有序大孔交联聚苯乙烯重金属吸附剂具有很大的优势,包括较强的吸附能力,较快的吸附速率和优良的再生性能。同时进行了p H和离子强度以及吸附剂与吸附质比值的影响的研究,溶液的吸附能力依赖于溶液的p H,此材料有一个较宽的工作区间。在298K、308K及318K下,进行了动力学研究,当重铬酸钾的初始浓度为100mg/L时,达到吸附平衡时所需的时间为120min,并且动力学实验数据较好地符合第二动力学模型。在等温吸附实验中,实验数据较好地符合Langmuir模型。最大吸附能力随着温度的增加而增加,当温度为318K时,最大吸附能力为431.0mg/g。热力学研究中显示吸附剂吸附重铬酸钾的行为是吸热的并且是自发的过程。另外,用氢氧化钠溶液进行了脱附实验,3DOM CLPS-g-PDMAEMA重金属吸附剂在脱附吸附15次后的吸附能力达到最初的90%以上,并且电镜扫描显示脱附后的材料仍然保持其三维有序大孔结构,证明3DOM CLPS-g-PDMAEMA重金属吸附剂具有优良的再生性能。2.通过胶晶模板法制备了孔径为500nm三维有序大孔二氧化硅(3DOM SiO_2)。3DOM SiO_2-g-Pt BA DETA重金属吸附剂制备过程如下:在3DOM SiO_2孔壁上通过活性聚合的方法引入聚甲基丙烯酸叔丁酯链段(Pt BA)得到3DOM SiO_2-Pt BA,3DOM SiO_2-Pt BA水解后与二乙烯三胺反应得到3DOM SiO_2-g-Pt BA DETA。通过研究p H的影响可知,当p H=5时,吸附量较高,达到90mg/g(初始浓度为100mg/g)。在298K、308K、318K的温度下,研究了时间对吸附量的影响,即动力学的研究,在298K下,当60min后吸附行为(初始浓度为100mg/g)达到平衡,吸附量不再增加。并且得到的动力学吸附数据更好地符合第一动力学模型。同时,研究了不同初始浓度的硝酸镉溶液对吸附量的影响,Freundlich模型可以更好地拟合其数据。热力学研究数据表明3DOM SiO_2-g-Pt BA-DETA对Cd~(2+)的吸附行为能够自发进行,并且是一个吸热过程。循环6次的材料对Cd~(2+)的吸附量达到初始吸附量的80%,并且电镜扫描显示脱附后的材料仍然保持其三维有序大孔结构,证明材料再生性能良好。
[Abstract]:Nowadays, heavy metal pollution has become one of the main problems of environmental pollution, which brings great harm to human health, such as causing kidney disease, liver disease, respiratory diseases and skin cancer. Heavy metal adsorbents have attracted more and more attention from scientists. In this paper, two kinds of three dimensional ordered macroporous heavy metal adsorbents were prepared. The main contents are as follows: 1. Three dimensional ordered crosslinked polystyrene porous material (3DOM CLPS),) with pore size of 500nm was prepared by colloidal crystal template method. (PDMAEMA), was introduced into polymethylaminoethyl methacrylate chain by active polymerization on three dimensional ordered crosslinked polystyrene. Compared with other adsorbents, the three dimensional ordered macroporous crosslinked polystyrene heavy metal adsorbents have great advantages, including strong adsorption ability, fast adsorption rate and excellent regeneration performance. The effects of pH, ionic strength and the ratio of adsorbent to adsorbate were also studied. The adsorption capacity of the solution depends on the pH of the solution, and the material has a wide working range. Kinetic studies were carried out at 298K ~ 308K and 318K. When the initial concentration of potassium dichromate was 100mg/L, the adsorption equilibrium time was 120 min, and the kinetic experimental data were in good agreement with the second kinetic model. In the isothermal adsorption experiment, the experimental data are in good agreement with the Langmuir model. The maximum adsorption capacity increases with the increase of temperature, and the maximum adsorption capacity is 431.0 mg / g when the temperature is 318K. Thermodynamic studies show that the adsorption of potassium dichromate by adsorbent is an endothermic and spontaneous process. In addition, the desorption experiment with sodium hydroxide solution showed that the adsorption ability of 3DOM CLPS-g-PDMAEMA heavy metal adsorbent reached above 90% after desorption for 15 times. The scanning electron microscope showed that the desorption material still maintained its three-dimensional ordered macroporous structure, which proved that the 3DOM CLPS-g-PDMAEMA heavy metal adsorbent had excellent regeneration performance. 2. Three dimensional ordered macroporous silica (3DOM SiO_2) with 500nm pore size was prepared by colloidal crystal template method. The preparation process of 3DOM SiO_2-g-Pt BA DETA heavy metal adsorbent was as follows: the method of active polymerization on the wall of 3DOM SiO_2 pore Preparation of 3DOM SiO_2-Pt BA, by introducing poly (tert-butyl methacrylate) (Pt BA) Synthesis of 3DOM SiO_2-g-Pt BA DETA. by hydrolysis of 3DOM SiO_2-Pt BA with diethylenetriamine By studying the effect of pH, we can see that when pH = 5, the adsorption capacity is higher and reaches 90mg/g (initial concentration is 100mg/g). The effect of time on the adsorption capacity was studied at the temperature of 298K ~ 308K ~ (318K). At 298K, the adsorption behavior (initial concentration of 100mg/g) reached equilibrium, and the adsorption capacity did not increase. The kinetic adsorption data obtained are in better agreement with the first kinetic model. At the same time, the influence of different initial concentration of cadmium nitrate solution on the adsorption capacity was studied. The Freundlich model can better fit the data. Thermodynamic data show that the adsorption of Cd~ (2) by 3DOM SiO_2-g-Pt BA-DETA can occur spontaneously and is an endothermic process. The adsorption amount of Cd~ (2) on the material after six cycles is 80% of the initial adsorption capacity. The SEM results show that the desorbed material still maintains its three-dimensional ordered macroporous structure, which proves that the regenerative property of the material is good.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X505;TQ424.3

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