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1、 密 级： 学校代码：10075 分类号： 学 号： 20091004 理学硕士学位论文 硅胶负载壳聚糖复合材料对重金属离子 的吸附动力学及热力学研究 学位申请人： 刘 盼 指导教师： 马志广 教授 学位类别： 理学硕士 学科专业： 物理化学 授予单位： 河北大学 答辩日期： 二一二年六月 Classified Index: CODE: 10075 U.D.C.: NO: 20091004 A Dissertation for the Degree of M. Science Kinetic and Thermodynamic Studies on the Adsorption of Heav
2、y Metal Ions onto Silica-Supported Chitosan Composite Materials Candidate：Liu Pan Supervisor：Prof. Ma Zhi-guang Academic Degree Applied for：Master of Science Specialty：Physical Chemistry University：Hebei University Date of Oral Examination：June, 2012 摘 要 I 摘 要 摘 要 随着全球工业的迅猛发展，重金属离子的污染问题日益严重。大量工业废水得不
3、到 良好的处理， 致使大量重金属离子进入生物链， 对人类的健康及生存造成了极大的危害， 因此急需寻找一种高效、简洁、廉价的处理重金属离子的方法。科研工作者一直以来都 非常关注重金属离子污染及处理的问题。目前常用的处理重金属离子的方法有：化学沉 淀法、氧化还原法、离子交换与吸附法、电解法等，其中吸附法以其价格低、来源广、 简单易行、处理效率高和无二次污染等优点而被人们广为关注。 广泛存在于自然界的壳聚糖含有很多活泼的氨基和羟基， 能够与一些重金属离子发 生配位，由于其无毒、易降解且不产生二次污染，因而在含重金属离子的废水处理中被 日益重视。但壳聚糖难溶于水、易溶胀、受 pH 影响过大等缺点限制了
4、其广泛应用。将 壳聚糖负载在硅胶上，生成以硅胶为基质的硅胶负载壳聚糖复合材料，可以增加壳聚糖 微球的比重和比表面积，加快其沉降速度，同时克服了单一使用壳聚糖作为吸附剂时存 在的一些缺点。 本文研究了硅胶负载壳聚糖复合材料对水溶液中 Ni2+、Co2+、Zn2+的吸附性能，分 别探索了吸附时间、吸附温度、初始浓度、溶液 pH 等条件对吸附性能的影响，确定了 吸附的最佳条件。同时对吸附的动力学及热力学过程进行了研究，在热力学方面，对吸 附过程用 Langmuir 等温吸附平衡模型和 Freundlich 等温吸附平衡模型分别进行模拟， 结 果表明，Ni2+和 Zn2+在水溶液中的吸附过程更适用于
5、Langmuir 等温吸附平衡模型，而 Co2+在水溶液中的吸附过程更适用于 Freundlich 等温吸附平衡模型，求出了相应的吸附 平衡常数，根据 Vant Hoff 方程计算出了吸附过程的热力学参数G?、H?、S?。在 动力学方面，用准一级动力学方程和准二级动力学方程分别对吸附过程进行拟合，结果 显示，Ni2+、Co2+、Zn2+三种离子的吸附过程都符合准二级动力学模型，按此模型计算 出了吸附过程的表观速率常数 k 和平衡吸附量 Qeq，进而计算出了表观活化能 Ea。 关键词 壳聚糖 硅胶 吸附 重金属离子 动力学 热力学 Abstract II Abstract With the ra
6、pid development of the global industry, the pollution of heavy metal ions becomes more and more serious gradually. Because of the improper deal of large quantity of industrial waste water, a large number of heavy metal ions flow into the food chain, which brings great bad effect to human health and
7、survivals. As a result, its necessary to find an efficient, simple and inexpensive method to deal with the heavy metal ions. Scientists have always been very concerned about the problems of pollution and treatment of heavy metal ions. Now the methods which are commonly used for the treatment of heav
8、y metal ions are as flows: chemical precipitation, oxidation and reduction, ion exchange and adsorption, electrolysis and so on. The method of adsorption is widely used because of its advantages such as low prices, a wide source of simple, high efficiency and no secondary pollution, etc. Chitosan fo
9、unded widely in nature contains a lot of lively amino and hydroxyl ligand which can occur with some heavy metal ions, and it is non-toxic, readily biodegradable and does not bring secondary pollution. So the chitosan is attracting more attention in the field of wastewater handling which contains hea
10、vy metal ions. However, chitosan is insoluble in water, easy to swell and easily influenced by the pH, which results in the limits of its wide application. When chitosan is loaded on silica gel to generate silica-supported chitosan composite materials, it can increase the proportion of chitosan micr
11、ospheres and the specific surface area, accelerate its settling velocity, while overcoming the single use of chitosan as some of the shortcomings in the adsorbent. This paper studied the adsorption of Ni2+, Co2+, and Zn2+ in aqueous solution onto chitosan-silicone composite materials and the influen
12、ce of physical and chemical parameters such as pH value, reaction time, temperature and initial concentration on the adsorption process. It determined the optimal adsorption conditions. Kinetics and thermodynamics of the adsorption were also studied. In thermodynamics, the adsorption process was sim
13、ulated with the Langmuir isotherm balance model and Freundlich isotherm balance model. The results showed that adsorption process of Ni2+ and of Zn2+ in aqueous solution is more applicable to Abstract III Langmuir isotherm equilibrium model and Co2+ is more applicable to the Freundlich isotherm equi
14、librium model. In this way we can get the corresponding adsorption equilibrium constant, according to Vant Hoff equation calculated the adsorption process thermodynamic parameters of G?, H? and S?. In Dynamics, the adsorption process was simulated with pseudo -first order kinetics equation and pseud
15、o -second order kinetics equation, and the result showed that the adsorption process of Ni2+, Co2+ and Zn2+ are in line with the pseudo-second order kinetics equation. With this model it calculates the apparent rate constant k and the equilibrium adsorption capacity Qeq, and then calculates the appa
16、rent activation energy Ea. Keywords Chitosan Silica Adsorption Heavy metal ions Kinetics Thermodynamics 目 录 IV 目 录 第 1 章 综述 1 1.1 重金属离子的来源、危害和去除方法 . 1 1.2 硅胶负载壳聚糖复合材料的制备及其性质 . 1 1.3 硅胶负载壳聚糖复合材料吸附重金属离子的研究进展 . 2 1.4 等温吸附热力学平衡模型 . 3 1.4.1 Langmuir 等温吸附平衡模型 . 3 1.4.2 Freundlich 等温吸附平衡模型 4 1.4.3 Temkin 等温吸附平衡模型 . 4 1.4.4 RedlichPeterson 等温吸附平衡模型 . 5 1.5 吸附动力学模型 . 6 1.5.1 准一级动力学方程 6 1.5.2 准二级吸附动
