Study Of Synthesis, Characterization And Surface Chemical Reaction Of Aluminosilicate Molecular Sieve

China is abundant in mineral resource, but large mining lead to environment pollution. The problem of beneficiation wastewater and soil pollution are concerned. Aluminosilicate mineral are the most common resource in the world, with wide distribution and huge content. In the natural environment, Aluminosilicate minerals play an important role in purification of water bodies via adsorption and degradation. In addition, aluminosilicate materials are widely used as adsorbent, ion-exchange material, catalyst, carrier and filler in multiple areas of industry. Aluminosilicate with a huge natural stock is easy and cheap to mine, and the synthesis technology of aluminosilicate is simple and mature. Therefore, aluminosilicate materials are chosen for management of beneficiation wastewater. The targeted aluminosilicate, kaolinite and molecular sieves, are synthesized by different methods. In order to extend application, aluminosilicate material are modified by ion-exchange. Then their structure, surface properties and application are systematically studied.In the study of doped kaolinite, targeted materials of doped kaolinite with different content of Co, Mn and Fe element?Co-KL, Mn-KL, Fe-KL? were synthesized by hydrothermal method. The doped kaolinite were characterized by XRD, BET, IR and potentiometric titrator so as to study the structure and surface properties of doped kaolinite. The study result shows that the lattice parameter b of doped kaolinite varies systematically with metal content. It implys that metal element may incorporate into the kaolinite structure by isomorphous substitution. The surface acid-base properties of doped kaolinite are studied by calculating and analyzing the data of potentiometric titrator. It is obvious that doping can change the surface acid-base properties of kaolinite. Surface site concentration?Hs? and surface site density?Ds? of doped kaolinite are increasing with the content of metal element. The specific surface area acid-base equilibrium constants of doped products are related to the content and type of doped element.In the study of molecular sieve, pure phase zeolites with the framework of FAU, GIS and ANA were synthesized by hydrothermal method, microwave-assisted hydrothermal method and microwave method with the same sol-gel precursor under different temperature and time. It find that microwave-assisted hydrothermal method is the most efficient for synthesis. A process of phase transformation during crystallization were studied by sample characterization of XRD, IR, SEM?EDS? and BET. The result shows that a process of phase transformation about FAU-GIS-ANA can be found when the energy is enough in synthetic system. zeolite with FAU, GIS and ANA framework can be obtained respectively by controlling the temperature and time of crystallization.The next experiment is modification and application of zeolite. Zeolite X?FAU? was modified and activated by ion exchanging with Ag⁺, Cu²⁺, Pb²⁺, then modified material was used to curb beneficiation wastewater with xanthate. Continuous online in situ attenuated total reflection Fourier-transform infrared?ATR-IR? spectroscopic technique was used to study the ion online exchanged process. This spectroscopic technique could be used to monitor the exchanged process and proves the reversibility of ion exchange. In the adsorbent experiment, zeolite material can adsorb xanthate effectively from beneficiation wastewater after partial Na+ in zeolite structure being exchanged by some tranthe sition metal cations. The result shows that the maximum online adsorption of zeolite FAU for butyl xanthate is 402 mg/g after zeolite FAU online ion activating by Cu²⁺ dilute solution. ATR-IR spectroscopic technique was used to study the behavior of butyl xanthate adsorbed on Ag-FAU surface. The maximum adsorption of Ag-FAU for butyl xanthate is 847 mg?g-1. The adsorption kinetic is studied by monitoring the intensity changes of the butyl xanthate characteristic peak at 1190 cm-1 of ATR-IR. The result shows that the adsorption kinetics could be well described by a pseudo-first-order kinetics reaction model. In the study of Pb-FAU material, the four adsorption isotherms of Pb-FAU adsorbing xanthate of different lengths conform to Langmuir model. ATR-IR spectroscopic technique was also used to study the adsorption kinetics about Pb-FAU adsorbing xanthates with different lengths. The result shows that this adsorption is a two-stage process. In the first stage, adsorption kinetics could be well described by a pseudo-first-order kinetics reaction model, while the diffusion is the rate-limiting step. In the second stage, adsorption kinetics can be described by a pseudo-second-order kinetics reaction model, while the chemical adsorption is the rate-limiting step.