新型微球状的钙铝镧复合材料的制备及其除氟性能研究

发布时间：2018-06-07 22:38

本文选题：钙铝镧复合材料 + 除氟　；参考：《武汉理工大学》2013年硕士论文

【摘要】：氟是人体维持正常生理机能活动不可缺少的微量元素之一,微量的氟是人体必需的,有利于骨骼的坚固性,但过量的氟对人体是有害的,主要损害牙齿的釉质、骨骼的成骨和破骨活动,并影响全身各组织器官,轻者出现氟斑牙和全身各个骨骼及关节部位疼痛等症状,较重者呈现关节僵硬及运动机能障碍,严重者呈现躯干变形和瘫痪,以致终生残废。所以,必须去除饮用水中过量的氟,使其达到低1.5mg／L的世界卫生组织标准。我国在《生活饮用水卫生标准》(GB5949-2006)中明确规定：饮用水中氟化物含量标准为不高于1.0mg/L。吸附法由于其处理效果好、工艺流程简单,而得到广泛应用。而吸附方法成败的关键在于吸附剂的适用性。一些天然材料如铝土矿、蛇纹石、沸石和膨润土等虽然原料较为经济,但吸附能力太差,将其改性后的吸附量虽然有所增加,但操作复杂,使用周期短。一些稀土类吸附剂除氟效率高,但单一的使用稀土元素成本较高,不适合大规模生产。因此开发一种低成本、高效率且具有操作简单、稳定性好、无二次污染、吸附容量大的新型吸附剂具有重要的科学和现实意义。本研究以四水硝酸钙、九水硝酸铝以及水合硝酸镧为原料,尿素为沉淀剂,采用一步水热法成功合成了钙铝镧复合除氟吸附剂。采用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、氮气吸附脱附法(BET)和X射线光电子能谱(XPS)等表征手段对所制备的样品进行了表征和分析。通过静吸附试验研究了该吸附剂的除氟性能。如pH值对吸附性能的影响、投加量对吸附性能的影响、吸附等温研究、接触时间对吸附性能的影响及吸附动力学研究、共存阴离子对吸附性能的影响和吸附剂的自然沉降等。Langmuir等温线模型较Freundlich等温线模型更能符合本实验吸附剂除氟的吸附进程且最大饱和吸附容量为26.17mg/g。通过吸附动力学的研究,发现二级动力学模型能更好的表述吸附剂对氟的吸附进程。共存阴离子对吸附剂除氟性能的影响遵循的规律为PO43-HCO3-SO42-NO3-Cl-。吸附剂除氟的适用pH值范围较大为3.0-11.0,在此范围内都有较佳的吸附性能。除了较好的吸附性能,所制备的样品形貌也非常新颖似棉花状且分散性、均匀性都较好。
[Abstract]:Fluorine is one of the essential trace elements for the human body to maintain its normal physiological function. The trace amount of fluoride is essential to the human body and is beneficial to the firmness of the skeleton. However, excessive fluoride is harmful to the human body and mainly damages the enamel of the teeth. Bone osteogenesis and osteoclast activity affect all tissues and organs of the whole body. Mild patients have symptoms such as dental fluorosis and pain in various bones and joints of the whole body. The heavier ones present stiffness and dyskinesia of the joints, and the severe cases present deformation and paralysis of the trunk. To be crippled for life. Therefore, excess fluoride in drinking water must be removed to the WHO standard of 1.5 mg / L lower. In "Sanitary Standard for domestic drinking Water" (GB5949-2006), it is clearly stipulated that the standard of fluoride content in drinking water is not more than 1.0 mg 路L ~ (-1) 路L ~ (-1) 路L ~ (-1) 路L ~ (-1). Adsorption method is widely used because of its good treatment effect and simple technological process. The key to the success or failure of the adsorption method is the applicability of the adsorbent. Some natural materials, such as bauxite, serpentine, zeolite and bentonite, are more economical, but their adsorption capacity is too poor. Some rare earth adsorbents have high defluorination efficiency, but the cost of using rare earth elements alone is high, so it is not suitable for mass production. Therefore, it is of great scientific and practical significance to develop a new adsorbent with low cost, high efficiency, simple operation, good stability, no secondary pollution and large adsorption capacity. Calcium aluminum-lanthanum complex adsorbent was successfully synthesized by one-step hydrothermal method with aluminum nitrate and lanthanum nitrate hydrate as raw materials and urea as precipitant. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), nitrogen adsorption and desorption (BET) and X-ray photoelectron spectroscopy (XPS). The defluorination performance of the adsorbent was studied by static adsorption test. For example, the influence of pH value on adsorption performance, the effect of dosage on adsorption performance, the isothermal study of adsorption, the influence of contact time on adsorption performance and the study of adsorption kinetics. Compared with Freundlich isotherm model, the effect of coexisting anions on adsorption properties and the natural deposition of adsorbent were more consistent with the adsorption process of fluoride removal by the experimental adsorbent. The maximum saturated adsorption capacity was 26.17 mg / g. Through the study of adsorption kinetics, it is found that the second-order kinetic model can better describe the adsorption process of fluorine. The effect of coexisting anions on the defluorination performance of adsorbents follows the rule of PO _ 43-HCO _ 3-SO _ 4 _ 2-NO _ 3-Cl _ (-). The suitable pH range of adsorbent for fluoride removal is 3.0-11.0, and the adsorbent has better adsorption property in this range. In addition to the better adsorption properties, the morphology of the prepared samples is also novel, cotton like, dispersibility and good uniformity.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：O647.3;R123

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