【作者】 闫冠杰；

【导师】 袁明亮；

【作者基本信息】 中南大学 ， 矿物材料学， 2009， 硕士

【摘要】 近年来,随着经济社会的快速发展,大量工业废水和生活污水排入天然水体,尤其是废水中的重金属离子严重影响人类的健康。结合实际情况,研究人员采用不同的吸附剂和处理方法解决日益严重的重金属离子污染问题。本文以浙江缙云斜发沸石为研究对象,采用不同方法对其改性,得到吸附性能较强的改性沸石。以磁性载体技术为基础,分别采用化学共沉淀法和物理黏结法使具有吸附特性的改性沸石与Fe₃O₄相结合,制备出不同的磁性天然沸石吸附剂。利用XRD、SEM、FT-IR、TG-DSC、氮吸附等温线和磁性能测试等方法对最佳磁性沸石进行表征。同时,研究磁性沸石对重金属离子的吸附性能,以探索其最佳吸附条件、吸附量和吸附机理。对天然沸石的改性及改性沸石对pb²⁺的吸附实验表明,氯化钠改性后的钠型沸石对pb²⁺的吸附性能较好,其对pb²⁺的吸附性能依赖于pH值的变化,在实验范围内其对pb²⁺的最大吸附量为66.99 mg/g。对于化学法制备的磁性沸石,氮吸附分析表明,磁性沸石（浓氨水、）、磁性沸石（NaOH）和钠型沸石的比表面积分别为100.90 m²/g、64.02 m²/g和25.13 m²/g。FT-IR分析指出,磁性沸石（浓氨水）的制备使Si-O（Si或Al）键反对称伸缩振动吸收峰的位置从1054.5 cm^-1变化到1039.3 cm^-1,这表明Fe³⁺类似于Al³⁺已进入钠型沸石的结构中。在不同的初始浓度下,磁性沸石和钠型沸石对pb²⁺、Cu²⁺和Cd²⁺的吸附实验表明,该吸附性能依赖于pH值的变化,其平衡吸附量随初始浓度的增加而增大。根据常见的液相吸附模型,对吸附等温线数据进行线性拟合,拟合后直线与线性Langmuir方程基本重合,这证实该吸附过程属单层Langmuir型吸附。计算结果表明,磁性沸石（浓氨水）、磁性沸石（NaOH）和钠型沸石对pb²⁺的单位质量吸附剂的单层饱和吸附量分别为130.72 mg/g、88.18 mg/g和65.92 mg/g。对于物理法制备的磁性沸石,沸石表面黏结的Fe₃O₄没有改变基体的结构,且使其比表面积增大。样品的磁性能测试证实,磁性沸石（氨基甲酸乙酯）和Fe₃O₄的磁化率分别为11.7 emu/g和39.8 emu/g。在不同的初始浓度下,磁性沸石（氨基甲酸乙酯）、磁性沸石（羧甲基纤维素钠）和钠型沸石对pb²⁺的吸附实验表明,随着初始浓度的增大平衡吸附量也不断增大,其最大吸附量分别为54.53 mg/g、84.00 mg/g和66.99 mg/g。在分离科学与技术领域,本文制备磁性天然沸石的方法具有独特的优势。从复杂多相体系中将重金属离子分离和再生不需要对废水进行预处理,随后通过外加磁场使饱和磁性沸石与作用体系分离。更多还原

【Abstract】 In recent years, with the rapid development of social economy, plenty of industrial wastes and sanitary sewages were poured into natural water, of which subsistent heavy metal ions can affect human health seriously. Given this problem, researchers resolve the worsening pollution caused by the heavy metal ions using different adsorbents and processing methods.In this paper, the clinoptilolite produced in Jinyun county of Zhejiang province as an object, which was modified by traditional methods in order to obtain the modified natural zeolite with high adsorption capacity. Then, on the basis of magnetic carrier technology, different magnetically modified zeolites （MMZ） were prepared by combining the modified zeolite with Fe₃O₄ via chemical co-precipitation method and physical adhesion process. The optimal MMZ was characterized by XRD, SEM, FT-IR, TG-DSC, N₂ adsorption isotherms and magnetization measurements. The adsorption of the MMZ for heavy metal ions was studied, and the optimal adsorption conditions, adsorption capacity and adsorption mechanism were also explored.Through the experiments of modification for the natural zeolite and of adsorption for Pb²⁺ on the modified zeolite, the conclusion can be drawn that the modified zeolite by NaCl （Na-zeolite） has the optimal adsorption for Pb²⁺. The adsorption of Pb²⁺ on the Na-zeolite is dependent on pH, and the maximum adsorption capacity of Pb in the initial concentration range studied reaches 66.99 mg/g.For the magnetically modified natural zeolites by chemical method: N₂ adsorption analysis shows that the specific surface areas of the MMZ （Ammonia）, MMZ （NaOH） and the Na-zeolite are 100.90 m²/g, 64.02 m²/g and 25.13 m²/g, respectively. According to the FT-IR spectra, the prepared MMZ （Ammonia） cause shift of the Si-0 （Si or Al） at 1054.5 cm^-1 to 1039.3 cm^-1, and the shift indicates that the Fe³⁺ cations similar with Al³⁺ cations embed into the framework of the Na-zeolite during preparation process. In different initial concentration, the adsorption tests of the MMZ and Na-zeolite for Pb²⁺, Cu²⁺ and Cd²⁺ shows that the adsorption is dependent on pH, and the equilibrium adsorbance increases with the increase of initial concentration. According to the general models of liquid phase adsorption, the data of adsorption isotherms is linear fitted, and the fitted curves and the lineared Langmuir curves are basically in coincidence. The fact shows that the adsorption process belonged with the monolayer Langmuir adsorption, and the maximum amount of adsorbed Pb²⁺ per mg of the MMZ （Ammonia）, MMZ （NaOH） and the Na-zeolite are 130.72 mg/g, 88.18 mg/g and 65.92 mg/g, respectively.For the magnetically modified natural zeolites by physical process: the structure of MMZ is not manifestly changed along with Fe₃O₄ coated the surface of Na-zeolite, but the specific area increases. The magnetization measurements confirm that the bulk magnetization of the MMZ （Urethane） and Fe₃O₄are 11.7 emu/g and 39.8 emu/g. In different initial concentration, the adsorption tests of the MMZ （Urethane）, MMZ （CMC） and Na-zeolite for Pb show that the equilibrium adsorbance increases with the increase of initial concentration, and the maximum amount of adsorbed are 54.53 mg/g, 84.00 mg/g and 66.99 mg/g, respectively.The use of the MMZ developed here offers a unique advantage in separation science and technology. The separation and recovery of heavy metal ions from a complex multiphase system can be accomplished without pretreatment, as the saturated MMZ can be isolated with an external magnetic field.更多还原