【作者】 高帅鹏；

【导师】 邹卫华； 李红萍；

【作者基本信息】 郑州大学 ， 化学工程（专业学位）， 2013， 硕士

【摘要】 天然沸石是一种常见的、廉价的污水处理材料,但是天然沸石往往含有杂质,制约了其吸附性能和离子交换能力。氢氧化镁是一种新型的污水处理材料,活性大、吸附能力强,但是由于其是粉末状,很难从水溶液中分离,制约其在废水处理中的应用。本文以氢氧化镁负载改性沸石的方法,制得复合材料改性沸石(MHMZ).该复合材料既有一般吸附材料的截留能力能够去除水溶液中的悬浮物,又能提高对水溶液中污染物的去除效果,且改性沸石为颗粒状,极易与水体分离。采用X射线荧光(XRF)、红外光谱(FT-IR)、扫描电镜(SEM). X射线粉末衍射(XRD)和扫描电镜原子能谱(SEM-EDS)的方法对改性前后的沸石进行了表征分析,采用静态吸附实验,研究了MHMZ对甲基橙(MO)、亮绿(LG)和镉离子(Cd2+)的单组分吸附行为,MO和Cd2+的双组分吸附行为及MO、LG和Cd2+的三组分吸附行为。MHMZ对MO、LG和Cd2+的单组分吸附体系,主要研究了吸附时间、pH值、吸附剂用量、盐离子浓度、温度及不同初始浓度等因素对吸附的影响。研究结果表明,改性后的沸石(MHMZ)的吸附能力显著提高,在298K时对MO、LG和Cd2+的最佳吸附时间分别为2h、5h和5h,最大吸附量分别为0.3016、0.1021和0.2745mmol·g-1,盐离子的存在会抑制MHMZ对三者的吸附。在298K下,研究了MHMZ对MO和Cd2+的双组分体系的吸附行为和对MO.LG和Cd2+的三组分的吸附行为。研究结果表明,MHMZ对MO和LG的吸附作用属于分子间作用力,而对Cd2+的吸附主要是离子交换吸附。MHMZ对双组分体系中MO和Cd2+的吸附过程存在吸附量增大的协同作用。MHMZ对三组分体系中MO、LG和Cd2+的吸附过程既有MO与Cd2+以及LG与Cd2+之间的协同作用,又有MO和LG之间的竞争吸附行为。解吸再生实验表明,0.1mmol·L-1的NaOH对Cd2+的解析效果最好,微波辐射法对LG有良好的解析效果,对MO的解析效果不明显。对于单组分体系,MHMZ对MO、LG和Cd2+平衡吸附行为均可以用Langmuir、Temkin以及Koble-Corrigan等等温吸附方程来描述,除此之外,MHMZ对Cd2+的吸附行为还可以用Redlich-Peterson方程来描述。对于MHMZ对MO和Cd2+的双组分体及MO、LG和Cd2+的三组分体系的吸附行为,均可以用Langmuir、Temkin方程描述。热力学分析表明,MHMZ对MO的吸附过程为放热过程,而对LG和Cd2+的吸附过程均为吸热反应。吸附动力学研究表明,MHMZ对MO、LG和Cd2+的单组分吸附符合准一级动力学方程和Elovich方程；MHMZ对MO和Cd2+的双组分体系的吸附符合准二级动力学方程和Elovich方程；对MO、LG和Cd2+的三组分体系的吸附行为可以用准一级动力学方程和Elovich方程描述。通过粒子内扩散方程拟合结果表明,膜扩散均不是唯一的速率控制步骤。更多还原

【Abstract】 Nature Zeolite, as one of low-cost and easily obtaining materials, is one of attractive adsorbents. However, the adsorption and ion exchange capacity of nature zeolite is very limited due to its microporous channels may be plugged and some impurities may adhere to the surface. Because of magnesium hydroxide is high activity, powerful adsorption, it is called green disposing reagent of waste water treatment. In this paper, we use the magnesium hydroxide modified zeolite (MHMZ), to solve the problem of the separation of the magnesium hydroxide powder after water treatment. Loading of magnesium hydroxide modified zeolite can improve the surface character of the original nature zeolite, and enhance the ability to removal adsorbate in aqueous solution.The nature and modified zeolite was characterized by X-ray fluorescence (XRF), Fourier transform infrared spectrum (FT-IR), Scanning electron microscope (SEM), X-ray diffraction (XRD) and Scanning electron microscopy-Energy dispersive spectroscopy (SEM-EDS). The batch adsorption experiments were conducted, to study the adsorption behavior of MHMZ adsorb methyl orange (MO), Light Green SF yellowish (LG) and the cadmium (Cd2+) in the single system. The competitive adsorption of the binary system of MO and Cd2+and the ternary system of MO, LG and Cd2+were also presented.The influence of several operating parameters for adsorption of MO, LG and Cd2+in single system, such as contact time, pH, adsorbent adsorbent dosage, the salt concentration, temperature and initial concentration were investigated in batch mode. The results showed that the adsorption capacity of the modified zeolite was improved significantly, and the optimal adsorption time of MO, LG and Cd2+were2h,5h and5h, respectively. The maximum adsorption capacity of MO, LG and Cd2+were0.3016,0.1021and0.2745mmol·g-1at298K, respectively. The presence of salt inhibited the adsorption of MO, LG and Cd2+in aqueous solution. Through the mechanism analysis and verified experiments, the results showed that the adsorption of MO and LG is belong to the intermolecular interactions, and that the adsorption of Cd2+is belong to ion exchange. The presence of MO on dye/metal binary solutions enhances the adsorption of MO and Cd2+on MHMZ. And in the adsorption of ternary system of MO, LG and Cd2+, there is not only enhances the adsorption of dyes and Cd2+on dye-metal solutions, but also the competitive adsorption between MO and LG Through desorption and regeneration experiments, we were found the best desorption reagent for Cd2+was0.1mmol·L-1NaOH, and the best way of regeneration was microwave radiation for LG, but for the regeneration of MO was ineffective.Through the analysis of the adsorption isotherm models, the equilibrium data for the single system of MO, LG and Cd2+were fitted well by Langmuir, Temkin and Koble-Corrigan isotherm models, and for the adsorption of Cd2+also fitted well by Redlich-Peterson model. In addition, adsorption behavior of the binary system of MO and Cd2+, and the ternary system of MO, LG and Cd2+can be approximately described with Langmuir and Temkin isotherm models. According to the thermodynamic analysis, the result suggest the adsorption MO onto MHMZ was spontaneous, exothermic nature in the adsorption process, and the adsorption of the LG and Cd2+onto MHMZ were spontaneous, endothermic.It is necessary to analysis the kinetics in adsorption processes. The Elovich model was a good choice to describe all the adsorption behaviour in this paper. Beyond that, the Pseudo-first-order model was also a good choice to describe the adsorption behaviour of the single system of MO, LG and Cd2+. The kinetics data of binary system of MO and Cd2+was fitted well by Pseudo-second-order kinetics model, and the kinetics data of ternary system of MO, LG and Cd2+was fitted well by Pseudo-first-order kinetics model. The kinetics of mechanism was investigated by use the Intra-particle diffusion analysis, it can be concluded that the actual process for all adsorption processes may contain the surface adsorption and intra-particle diffusion.更多还原