【作者】 鲁峰；

【导师】 常玥；

【作者基本信息】 西北师范大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 随着复合材料科学的不断发展,人们对经改性处理的无机复合材料的需求大幅增加。由于坡缕石粘土储量丰富、价格低廉、物理化学性质稳定等优点,将其经过不同方法和改性剂制备,得到的复合材料可以满足不同领域的要求。坡缕石表面可以引入不同的有机官能团,这些官能团能够和金属很好的螯合,提高了改性坡缕石对金属的吸附能力,使坡缕石得到了更广泛的应用。本文在坡缕石性质、改性方法及应用的基础上,主要做了以下工作:1、提纯的坡缕石经季铵盐活化后与硅烷偶联剂γ-胺丙基三甲氧基硅烷(APS)反应,得到表面被氨基修饰的坡缕石,再通过二硫化碳和氨基的反应引入了螯合能力强的硫代氨基官能团,得到改性坡缕石吸附剂。文章中详细研究了改性坡缕石对Cu(II)的吸附行为,考察了溶液pH值、吸附时间、溶液浓度以及温度对吸附量的影响,同时还对坡缕石原土和改性坡缕石对Cu(II)的吸附机理进行探讨。2、坡缕石粘土经聚乙烯醇(PVA)处理得到PVA/PGS复合吸附剂,并利用FT-IR、SEM、TG和XRD对其进行了表征。通过考察溶液酸度、吸附时间、初始浓度和温度对吸附量的影响,表明在100 mg/L的初始浓度溶液中,pH约为6时,PVA/PGS的最大吸附量达43.2 mg/g(PGS的最大吸附量是27.5 mg/g)。吸附过程经动力学方程及等温吸附方程拟合,结果显示吸附过程符合准二级动力学模型、Langmuir方程,同时计算了吸附过程的熵变、焓变和吉布斯自由能变,结果表明该吸附过程是自发进行的放热过程。3、以聚乙烯醇改性坡缕石,通过接枝共聚的方法引入聚丙烯腈,将腈基官能团在碱性环境的盐酸羟铵溶液中转化为偕胺肟基。本文中还讨论了酸度、时间、初始浓度和温度因素对吸附量的影响和吸附机理。当pH值约为6,偕胺肟基坡缕石对Cu(II)的吸附量达最大。动力学实验表明,吸附时间为70min时达到吸附平衡。动力学拟合结果显示,吸附过程符合准二级动力学模型,粒子扩散过程是吸附速控步过程,但不是唯一的速决步过程。Langmuir吸附模型较高的线性拟合常数说明吸附过程是单层吸附。4、表面经硅烷偶联剂(APS)修饰的坡缕石与甲基丙烯酸甲酯发生麦克尔加成反应后,再与乙二胺发生胺解反应,得到聚酰胺-胺键合坡缕石吸附剂。重点研究其对铅离子的吸附能力,实验结果表明:当pH值约为6,金属离子浓度为100 mg/L时,聚酰胺-胺键合坡缕石对Pb(II)的吸附量达63.54 mg/g (坡缕石原土的吸附量为31.5 mg/g)。动力学实验表明,吸附过程符合准二级动力学模型;等温吸附模型拟合结果显示,Langmuir吸附模型有较高的线性拟合常数说明吸附过程是单层吸附。更多还原

【Abstract】 With the development of functionalized and composite materials, the requirement of modified inorganic materials was increased rapidly. As palygorskite clay is abundant, low cost, in addition, possess stable physical and chemical properties, the clay modified with various methods and different modifier meet the requirements of different areas. Palygorskite surface can introduce different organic functional groups, these functional groups can chelate metal ions and improve the adsorption capacity of metal ions, so that palygorskite has been more widely used. Based on the review of the properties and the applications of palygorskite, the dissertation included following contents:1. Functional palygorskite was prepared from purified palygorskite and characterized by the method of IR and element analysis. The exchange between ammonium salt containning hydroxyl and Ca2+, Mg2+ of palygorskite layer increased the number of -OH, NH2-(CH2)3-Si(OMe)3 was connected to the surface of palygorskite by dehydration with -OH. After dehydration, functional groups with the chelating ability were introduced by the reaction between Carbon disulfide and Amino group.the adsorption ability of modified palygorskite for Cu(II) was investigated. The influences of the pH, contact time, concentration of Cu(II) and temperature on the adsorption were discussed. In addition, the article discussed the adsorption mechanism of palygorskite and modified palygorskite for Cu(II).2. Palygorskite (PGS) was modified with aqueous poly(vinyl alcohol) (PVA) to obtain hybrid adsorbent of PVA/PGS. It was characterized by the methods of TG, SEM and FT-IR. The adsorptions of Cu(II) ions from aqueous solution with PGS and PVA/PGS were studied. The effects of acidity, contact time, initial concentration of Cu(II) ions and temperature were investigated. At pH 6 and with initial Cu(II) concentration of 100 mg/L, PVA/PGS can achieve a maximum adsorption capacity of up to 43.2 mg/g (in comparison with 27.5mg/g for PGS). The adsorption process is correlated with the pseudo-first and second-order kinetic model and Intraparticle diffusion model. The isotherms were simulated by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models. The thermodynamic parameters, such as the change of free energy, enthalpy and entropy were also calculated.3. Amidoxime palygorskite was prepared by graft copolymerization. PVA has strong adhesive capacity to the oxide surface with the -OH groups. After palygorskite was modified with poly(vinyl alcohol)(PVA), the composite material was introduced the polymer containning cyano functional group, The cyano functional group was reduced to amidoxime in the hydroxyl ammonium hydrochloride solution. In addition, the article discussed the adsorption mechanism of palygorskite and modified palygorskite for Cu(II). When the pH value of about 6, adsorption capacity of amidoxime palygorskite for Cu (II) can reach the largest. Kinetic experiments show that the adsorption reach equilibrium when the adsorption time is 70min, the adsorption process is correlated with the pseudo- second-order kinetic model. The higher linear regression constants of langmuir adsorption model show that Adsorption process is monolayer adsorption.4. Palygorskite was modified with silane couple agent, Amino group and methyl acrylate occurs Michael reaction, after that, ethylenediamine can occur aminolysis reaction with Ester. the adsorption results of adsorbent for Pb(II) as follows: adsorption capacity of palygorskite functionalized by dendrimer-like polyamidoamine for Pb (II) can reach 63.54mg/g (in comparison with 31.5mg/g for PGS), When the pH value is about 6 and the metal ion concentration is 100 mg/L. The adsorption process is correlated with the pseudo-first and second-order kinetic model and Intraparticle diffusion model. The isotherms were simulated by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models.更多还原