金属亚铁氰化合物复合微球的制备及其吸附性能研究

发布时间：2018-07-09 21:41

本文选题：金属亚铁氰化物 + 羧甲基纤维素钠　；参考：《西南科技大学》2017年硕士论文

【摘要】：自2011年福岛核电站发生核事故以来,放射性核素的废液处理技术已经成为重点研究的内容之一,而铯在放射性核素中占很大的份额,由于其半衰期长,对人类的健康带来严重的危害,因此,除去废水中的铯离子十分必要。吸附法因其成本低、工艺简单和高效而备受关注,但是其除铯效果受吸附剂的制约。金属亚铁氰化物具有独特的选择性、极高的化学稳定性等优点,因此,此材料一直以来是放射性铯废水处理领域的研究热点之一。羧甲基纤维素是一种水溶性纤维素醚,由于其在多价离子的存在下可以形成凝胶微球而常作为增稠剂、包埋剂等。本文以羧甲基纤维素钠为载体,以金属亚铁氰化物为活性成分,采用包埋法、原位合成法等固化技术分别制备了羧甲基纤维素钠/普鲁士蓝交联镧凝胶微球(CMC/PB-La)、普鲁士蓝微球(CMC-PB)和亚铁氰化铜复合颗粒(CMC-KCu FC)吸附材料,详细探讨三种吸附材料对模拟含铯废水中Cs+的吸附去除性能,并研究了三种吸附剂对铯离子的吸附动力学、热力学及吸附等温模型,以及吸附剂的洗脱和可能的吸附机理,主要研究结果如下:1、利用包埋法制备了CMC/PB-La凝胶微球吸附剂,考察了p H、吸附剂用量、反应时间、初始铯离子浓度和辐射稳定性等因素对铯的吸附性能影响。得出制备CMC/PB-La凝胶微球的最佳吸附条件为:吸附剂用量为1 g/L,吸附时间为1000 min,温度为298.15 K,溶液中K+的存在会影响吸附剂除铯效果;吸附过程符合Freundlich等温吸附模型和准二级动力学模型,当温度低于328.15 K,CMC/PB-La凝胶微球吸附铯离子是自发的吸热过程,具有较好的辐射稳定性;并通过SEM、FT-IR、EDX和XPS对吸附剂进行表征测试。推测CMC/PB-La凝胶微球吸附铯离子的机理是物理吸附和化学吸附共同作用的结果。2、采用原位合成法制备了CMC-PB凝胶微球吸附材料,并研究了其吸附铯离子的特性。结果表明吸附铯离子的优化条件为:p H为5,吸附剂的量为1.2 g/L,吸附时间为60 min,吸附铯离子起主要作用的是CMC-PB微球上的PB晶体。并对等温模型、动力学模型及热力学进行了研究,结果表明:吸附过程符合Langmuir等温模型及准二级动力学模型,最大吸附量为115.04 mg·g~(-1),从计算的热力学数据可知,CMC-PB吸附铯离子是自发的吸热过程。通过IR、XRD和XPS等手段有效的证明了PB被成功负载到了CMC载体上。其对铯离子吸附机理主要是化学离子交换吸附和物理吸附的作用。3、采用原位合成法制备了CMC-KCu FC复合颗粒吸附剂;批量实验考察了p H、吸附剂用量、接触时间、初始铯离子浓度和共存离子等对CMC-KCu FC复合颗粒吸附性能的影响;采用SEM、FTIR、EDX和XRD等手段对合成的材料进行分析。得出CMC-KCu FC复合微球吸附铯离子的优化条件为:p H为5,吸附剂的量为0.4 g/L,吸附时间为600 min,温度为298.15 K,且在K~+、Na~+、Ca~(2+)、Mg~(2+)和Li~+等阳离子共存条件下,其对铯的分配系数影响大小顺序为:K~+Na~+Ca~(2+)Mg~(2+)Li~+。1.0 mol·L~(-1) KNO_3对铯离子的脱附率最大,其脱附率为36.8%。CMC-KCu FC复合颗粒吸附Cs~+的过程符合拟二阶动力学模型,可用Freundlich模型来描述。通过SEM、IR和XRD手段有效的证明了KCu FC被成功负载到了CMC载体上。4、讨论了柱高、流速和铯离子的浓度对CMC-KCu FC复合颗粒动态吸附的影响,结果表明,穿透点和耗竭点随着柱高的增加而延后,穿透点和耗竭点随着浓度和流速的的升高而缩短。
[Abstract]:Since the nuclear accident in Fukushima nuclear power plant occurred in 2011, the treatment technology of radioactive nuclide waste liquid has become one of the key research contents, and cesium occupies a large share in the radionuclide. Because of its long half-life, it has brought serious harm to human health. Therefore, it is necessary to remove cesium ions from the wastewater. Low, simple and efficient technology has attracted much attention, but its removal of cesium is restricted by adsorbents. Metal ferrocyanide has the advantages of unique selectivity and high chemical stability. Therefore, this material has always been a hot spot in the field of radioactive cesium wastewater treatment. Carboxymethyl cellulose is a water-soluble cellulose ether, which is a kind of water-soluble cellulose ether. In the presence of polyvalent ions, gel microspheres can be formed and often used as thickeners and embedding agents. In this paper, carboxymethyl fibrin sodium / Prussian blue crosslinked lanthanum Gel Microspheres (CMC/PB-La) were prepared by encapsulation and in situ synthesis using sodium carboxymethyl cellulose as the carrier and metal ferrocyanide as the active component. Prussian blue microspheres (CMC-PB) and copper ferrocyanide composite particles (CMC-KCu FC) adsorbents were used to investigate the adsorption and removal of Cs+ in simulated cesium containing wastewater by three kinds of adsorbents. The adsorption kinetics, thermodynamics and adsorption isothermal model of three kinds of adsorbents for cesium ions were studied, and the elution and possible adsorption mechanism of adsorbents were also studied. The main results are as follows: 1, the CMC/PB-La gel microsphere adsorbent was prepared by the embedding method. The effects of P H, the amount of adsorbents, the reaction time, the initial concentration of cesium ions and the radiation stability on the adsorption properties of cesium were investigated. The optimum adsorption conditions for the preparation of CMC/PB-La gel microspheres were obtained as follows: the dosage of adsorbents was 1 g/L and the adsorption time was 10. 00 min, the temperature is 298.15 K, the presence of K+ in the solution affects the effect of the adsorbents in the removal of cesium; the adsorption process conforms to the Freundlich isothermal adsorption model and the quasi two stage kinetic model. When the temperature is below 328.15 K, the adsorption of cesium ions by CMC/PB-La gel microspheres is a spontaneous endothermic process, with good radiation stability, and through SEM, FT-IR, EDX and XPS pairs. The mechanism of adsorbents was tested. The mechanism of the adsorption of cesium ions by CMC/PB-La gel microspheres was the result of the interaction of physical adsorption and chemical adsorption.2. The adsorption materials of CMC-PB gel microspheres were prepared by in situ synthesis method, and the characteristics of the adsorption of cesium ions were studied. The results showed that the optimum conditions for the absorption of cesium ions were as follows: P H was 5, adsorbents were adsorbents. The adsorption time is 1.2 g/L and the adsorption time is 60 min. The adsorption of cesium ions is the main function of the PB crystal on the CMC-PB microspheres. The isothermal model, kinetic model and thermodynamics are studied. The results show that the adsorption process conforms to the Langmuir isothermal model and the quasi two order kinetic model, the maximum adsorption amount is 115.04 mg. G~ (-1), from the calculated heat. It is known that CMC-PB adsorption of cesium ions is a spontaneous endothermic process. By means of IR, XRD and XPS, it is proved that PB has been successfully loaded onto the CMC carrier. The mechanism of the adsorption of cesium ions is mainly the action of chemical ion exchange adsorption and physical adsorption, and the CMC-KCu FC composite particle adsorbent is prepared by in situ synthesis method. The effects of P H, amount of adsorbents, contact time, initial concentration of cesium ions and coexisting ions on the adsorption properties of CMC-KCu FC composite particles were investigated. The synthetic materials were analyzed by means of SEM, FTIR, EDX and XRD. The optimum conditions for the adsorption of cesium ions by CMC-KCu FC composite microspheres were as follows: P H was 5, and the amount of adsorbent was 0.4. With a time of 600 min and a temperature of 298.15 K, and under the coexistence of K~+, Na~+, Ca~ (2+), Mg~ (2+) and Li~+, the order of the influence on the distribution coefficient of cesium is: K~+Na~+Ca~ (2+) Mg~. The two order kinetic model can be described by the Freundlich model. By means of SEM, IR and XRD, it is proved that KCu FC is successfully loaded onto.4 on the CMC carrier. The influence of column height, velocity and concentration of cesium ions on the dynamic adsorption of CMC-KCu FC composite particles is discussed. The results show that the penetration point and the exhaustion point are postponed with the increase of column height. The point and exhaustion point shorten with the increase of concentration and velocity.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O647.3

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