壳聚糖—钙配合物的构建及其对饮用水的高效脱氟研究

发布时间：2018-07-25 07:32

【摘要】：氟是人体必需的微量元素之一，人体主要通过饮水摄入，但长期过多的氟摄入则会对人体健康造成不同程度的危害，如氟斑牙、氟骨症、甚至是中枢神经等多系统的全身性疾病。自上世纪70年代以来，水体氟污染的控制研究一直是国内外环保及卫生领域的重要课题。吸附法作为一种简便高效的水处理方法，被广泛研究用于环境污染的治理。在众多低值吸附剂中，天然高分子物质壳聚糖因分子中含有大量的氨基和羟基活性基团，，且环境友好，在水处理领域具有广阔的应用前景。本研究以氯化钙和磷酸二氢钾为改性剂，制备了壳聚糖-钙配合物小球吸附材料，以高效去除饮用水中的氟离子。分别研究了（1）壳聚糖-钙配合物小球吸附材料的最佳制备条件；（2）吸附时间、溶液pH值、吸附质的初始浓度、共存离子等因素对改性吸附剂吸附水中氟离子的性能影响；（3）改性壳聚糖对氟离子的吸附动力学和热力学研究，得到相应的吸附动力学和热力学模型及相关参数；（4）改性壳聚糖的表征与机理研究；（5）改性壳聚糖对实际含氟饮用水的净化（6）改性壳聚糖的脱附再生。结果表明：（1）采用1.2g氯化钙，0.2g磷酸二氢钾对2g壳聚糖进行改性处理，能够得到最佳的脱氟效果；吸附反应在4h时基本达到吸附平衡，且对氟离子的吸附条件比原壳聚糖有更宽泛的pH条件适用范围；阳离子对改性壳聚糖吸附氟离子影响很小，阴离子对其影响为CO2—3 HCO—3——3 PO4 SO2—4 ClNO——3 NO2。（2）准二级动力学方程和Langmuir等温方程能适宜的描述改性壳聚糖对氟离子的吸附行为；（3）通过同步辐射X射线吸收精细结构（XAFS）、场发射扫描电镜（FESEM）、透射电镜（TEM）、X射线衍射（XRD）、傅里叶变换红外（FTIR）等表征方法获得了吸附材料的组成与表面特性，并提出了可能的吸附机制。（4）壳聚糖-钙配合物小球对氟离子初始浓度为10mg/L的井水、河水、自来水除氟效果达到90%以上，剩余氟离子浓度达到1.0mg/L以下。（5）使用NaOH溶液能够有效对饱和吸附后的壳聚糖材料进行脱附再生。
[Abstract]:Fluorine is one of the essential trace elements in human body. The human body is mainly ingested through drinking water, but the long-term excessive intake of fluorine will cause varying degrees of harm to human health, such as dental fluorosis, bone fluorosis, Even systemic diseases of multiple systems such as the central nervous system. Since the 1970s, the control of water fluoride pollution has been an important subject in the field of environmental protection and hygiene at home and abroad. As a simple and efficient water treatment method, adsorption method has been widely used in environmental pollution control. Among the low value adsorbents, chitosan, a natural macromolecule, has a wide application prospect in the field of water treatment because it contains a large number of amino and hydroxyl groups and is environmentally friendly. Using calcium chloride and potassium dihydrogen phosphate as modifiers, the adsorbent of chitosan calcium complex was prepared to remove fluoride ion from drinking water efficiently. (1) the optimum conditions for preparation of chitosan-calcium complex microspheres were studied, (2) the effects of adsorption time, pH value of solution, initial concentration of adsorbate, coexistence ion and other factors on the adsorption properties of fluorine ions in water were studied. (3) the adsorption kinetics and thermodynamics of the modified chitosan for fluorine ions were studied, and the corresponding adsorption kinetics and thermodynamic models and related parameters were obtained, (4) the characterization and mechanism of the modified chitosan; (5) purification of drinking water containing fluorine by modified chitosan (6) desorption and regeneration of modified chitosan. The results showed that: (1) the optimum defluorination effect could be obtained by using 1.2g calcium chloride 0.2g potassium dihydrogen phosphate to modify 2g chitosan, and the adsorption equilibrium was achieved after 4 hours of adsorption. The adsorption conditions of fluorine ions were wider than that of chitosan, and cation had little effect on the adsorption of fluoride ions by modified chitosan. The effect of anions on it is that CO2-3 HCO-3--3 PO4 SO2-4 ClNO--3 no _ 2. (2) Quasi-second-order kinetic equation and Langmuir isothermal equation can describe the adsorption behavior of modified chitosan for fluorine ion. (3) the composition and surface properties of the adsorbed materials were obtained by synchrotron radiation X-ray absorption fine structure (XAFS), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD), (XRD), Fourier transform infrared (FTIR), etc. The possible adsorption mechanism was also proposed. (4) the removal efficiency of fluorine in well water and river water with initial concentration of fluorine ion was more than 90%. The concentration of residual fluoride is below 1.0mg/L. (5) the adsorbed chitosan material can be desorbed and regenerated effectively by using NaOH solution.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU991.2

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