普鲁士蓝纳米材料对水中铯离子的吸附及其生物毒性研究

发布时间：2018-03-22 21:06

本文选题：普鲁士蓝　切入点：聚乳酸　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：核电事业的快速发展,造成大量的放射性废水排放到水环境中,对环境和人类健康产生威胁。作为放射性废水的主要成分,铯离子的污染日益严重。纳米普鲁士蓝(PB NPs)对铯离子有特异的吸附能力,近年来作为吸附剂应用在含铯废水的净化,但是实际应用中却发现纳米普鲁士蓝容易聚集、分离困难,易给环境带来次生污染。另外,纳米普鲁士蓝的生物毒性缺少系统性的深入研究,这给纳米普鲁士蓝的推广应用和水环境安全带来隐患。本文以生物可降解的聚乳酸作为纳米普鲁士蓝的载体,构建了普鲁士蓝纳米粒子与聚乳酸微球的复合体,在此基础上设计了可分离式的磁性普鲁士蓝纳米球吸附剂用于水中铯的去除,考察温度、pH、时间和初始浓度等因素对去除铯离子的影响,利用吸附等温线、吸附动力学与吸附热力学方程研究吸附机理。并系统地研究了不同粒径和不同化学组成的纳米普鲁士蓝的生物毒性,评价它们的生物安全性,为含铯等放射性废水处理和环境安全奠定了理论基础和基本保障。在聚乳酸微球表面固定纳米普鲁士蓝,构建了普鲁士蓝微球(PB-MCs)进行吸附水中铯离子。PB-MCs为规则球形,平均粒径是2.31±0.04μm,铁元素含量为5.11±0.54%。在293 K时,PB-MCs可将浓度为40mg/L的铯离子溶液降至12mg/L,铯离子的去除率达到70.26%,吸附量为4.01mg/g。PB-MCs的最佳pH范围为5~9,吸附平衡时间为120 min,对铯离子最大吸附容量为4.85 mg/g,等温吸附过程符合朗格缪尔模型;吸附动力学符合准二级拟合模型;吸附过程受到颗粒内扩散步骤控制。吸附过程是自发进行的,属于吸热反应。进一步增强吸附效能和分离特性,以聚乳酸纳米球做为载体,设计了靶向分离的磁性普鲁士蓝纳米球(MPBNs),内部包埋顺磁性四氧化三铁纳米粒子,表面负载纳米普鲁士蓝。MPBNs为球形,粒径是268.2±1.4 nm,铁元素含量为40.01%,饱和磁化强度为41.71 emu/g,可以通过磁分离回收。在293K时,MPBNs可使浓度为40mg/L的铯离子溶液降至4.8mg/L,铯离子的去除率达到82.46%,吸附量为16.49 mg/g。MPBNs对铯离子吸附的最优pH为5~9,吸附平衡时间为60 min,最大的吸附容量为17.03mg/g,与PB-MCs相比,吸附效能得到显著增强。此外,MPBNs通过外加磁场快速分离,吸附过程是吸热反应;吸附等温线适合弗兰德里希模型;吸附动力学符合准二级拟合模型;吸附过程受到颗粒内扩散步骤控制。为使纳米普鲁士蓝能够安全地用于含铯废水处理中,开展了不同普鲁士蓝纳米材料的生物毒性研究,依次合成了不同粒径(15 nm、25 nm、45 nm、85 nm)和不同化学组分(Fe3O4@PB NPs和Au@PB NPs)的纳米普鲁士蓝进行毒性比较。细胞实验表明,不同形式的纳米普鲁士蓝对细胞生长影响具有一定的尺寸、时间和浓度依赖效应。细胞电镜实验捕捉到纳米普鲁士蓝以胞饮方式进入细胞,可以单个和簇状分布在细胞中,使细胞形态发生改变,其中Fe3O4@PB NPs能进入到细胞核中,被细胞摄入最多。动物实验表明:小鼠尾静脉注射35mg/kg的一个月内,不同形式的纳米普鲁士蓝没有对小鼠的组织产生损伤,未产生毒性作用,可以安全有效地应用于含铯等污水处理中。本论文研制了普鲁士蓝微球和磁性普鲁士蓝纳米球吸附剂,兼具分离和吸附铯离子的特性,在放射性污水处理中有广阔前景。通过对纳米普鲁士蓝的生物毒性比较研究发现,在小于35mg/kg的注射剂量内,不同形式的纳米普鲁士蓝在细胞水平和组织水平没有改变生物学特征。因此,普鲁士蓝纳米材料吸附剂为环境领域提供了一类更加安全高效的材料,为实际含铯废水的处理提供了技术保障和理论基础。
[Abstract]:The rapid development of nuclear power industry, causing large amounts of radioactive wastewater discharged into the aquatic environment, pose a threat to human health and environment. As the main component of radioactive wastewater, cesium ion pollution is becoming increasingly serious. Nano Prussian blue (PB NPs) has a specific adsorption capacity of cesium ion in recent years, as the adsorbent in the purification of cesium containing wastewater, but in practice found that nano Prussian blue easy aggregation, difficult separation, easy to bring secondary pollution. In addition, the lack of systematic research of the biological toxicity of nano Prussian blue, which brings hidden trouble to the popularization and application of nano Prussian blue and water environment safety. The biodegradable polylactic acid as the carrier of nano Prussian blue, Prussian blue nanoparticles and constructed the polylactic acid microspheres complex, on the basis of the design of the Prussian blue nano magnetic separation type ball Adsorbent for water cesium removal effects of temperature, pH, influencing factors, time and initial concentration on the removal of cesium ions, the adsorption isotherm, adsorption kinetics and adsorption thermodynamics equation of adsorption mechanism. And studied the biological toxicity of Prussian blue nanoparticles of different size and chemical composition, biological safety evaluation they laid the basic guarantee, and the theoretical basis for containing cesium and other radioactive wastewater treatment and environmental safety. In poly lactic acid microspheres immobilized surface of Prussian blue, Lan Weiqiu constructed the Prussian (PB-MCs) adsorption water cesium ion.PB-MCs regular sphere, the average particle size is 2.31 + 0.04 m, the iron content is 5.11 in 293 K + 0.54%., PB-MCs the concentration of cesium ion solution of 40mg/L to 12mg/L, cesium ion removal rate reached 70.26%, the adsorption capacity for the best pH 4.01mg/g.PB-MCs range is 5~9, adsorption The equilibrium time is 120 min, the maximum adsorption capacity of cesium ion is 4.85 mg/g, the isothermal adsorption process with the Langmuir model; the adsorption kinetics of the quasi two level fitting model; the adsorption process by intra particle diffusion control. The adsorption process was spontaneous and endothermic reaction. To further enhance the adsorption efficiency and separation characteristics of poly lactic acid nanoparticles as carrier, the design of targeted magnetic nanoparticles separation of Prussian blue (MPBNs), encapsulated paramagnetic magnetic ferroferric oxide nano particles, surface loaded nano Prussian blue.MPBNs spherical particle size is 268.2 + 1.4 nm, the iron content is 40.01%, the saturation magnetization is 41.71 emu/g, the magnetic separation and recovery in 293K, MPBNs can make the concentration of cesium ion solution of 40mg/L to 4.8mg/L, cesium ion removal rate reached 82.46%, the adsorption capacity for optimal pH 16.49 mg/g.MPBNs for cesium ion adsorption For 5~9, the adsorption equilibrium time is 60 min, the maximum adsorption capacity is 17.03mg/g, compared with PB-MCs, the adsorption efficiency was significantly enhanced. In addition, MPBNs rapid separation by external magnetic field, the adsorption process is endothermic reaction; adsorption isotherms for the Fran Freiderich model; dynamic adsorption accords with the quasi two stage model; the adsorption process by particle diffusion step control. The nano Prussian blue can be safely used in the treatment of wastewater containing cesium, carried out the study on biological toxicity of different Prussian blue nano materials, followed by the synthesis of different size (15 nm, 25 nm, 45 nm, 85 nm) and different chemical components (Fe3O4@PB NPs and Au@PB NPs) nano Prussian blue. Cell toxicity experiments showed that nano Prussian blue with different forms of a certain size effect on cell growth, cell concentration and time dependent effect. The experimental electron microscope to capture nano Prew People in blue pinocytosis into cells, and can be a single cluster distribution in cells, the changes in cell morphology, in which Fe3O4@PB NPs can enter into the nucleus, cell intake most. Animal experiments show that: a month mice tail vein injection of 35mg/kg in nano Prussian blue in different forms of mice tissue injury, no toxicity, safety can be effectively applied to containing cesium and other wastewater treatment. This paper developed the Prussian blue microspheres and magnetic nanoparticles of Prussian blue adsorbent, with characteristics of separation and adsorption of cesium ions, has broad prospects in radioactive wastewater treatment. Through the comparative study on biological toxicity of nanoparticles Prussian blue was found in the injection amount is less than 35mg/kg, nano Prussian blue different forms did not change the biological characteristics at the cellular level and organization level. Therefore, the Prussian blue nano Material adsorbents provide a kind of more safe and efficient materials in the field of environment. It provides a technical support and theoretical basis for the treatment of actual cesium containing wastewater.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X771;TB383.1;O647.3

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