改性SiO2聚合物微球对阳离子染料的吸附行为

Adsoption Behavior of Cationic Dyes on Modified SiO2 Polymer Microspheres

本文以3-氨丙基三乙氧基硅烷(KH-550)为改性剂,先在碱性条件下对SiO2改性得到改性二氧化硅(Poly-SiO 2),再以丙烯酸、丙烯酰胺为单体,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用反相悬浮法对Poly-SiO2进一步改性,制备了一种改性SiO2聚合物微球(AA-Poly-SiO2)。通过傅立叶变换红外光谱、热重分析、扫描电子显微镜、X射线粉末衍射分析其结构特性。考察了AA-Poly-SiO2对含氮阳离子染料亚甲基蓝、碱性品红、甲基紫、乙基紫的吸附性能,研究了时间、pH、吸附剂用量、初始浓度对吸附染料的影响,以及吸附动力学和等温吸附过程。得到的AA-Poly-SiO2的平均尺寸为8.20μm,比表面积为0.0725 m2/g。其等温吸附符合Langmuir模型,吸附过程遵循Langmuir等温吸附和准二级动力学模型,为单层化学吸附。该AA-Poly-SiO2对乙基紫的最大吸附容量可达1000 mg/g。与常规聚丙烯酰胺微球相比,AA-Poly-SiO2显示出更高的吸附容量,可以循环使用5次,吸附率仍在78%以上。

In this paper,functionalized silica(Poly-SiO2)was firstly prepared with 3-aminopropyltriethoxysilane(KH-550)under alkaline conditions.A modified silica polymer microsphere(AA-Poly-SiO2)was then synthesized using acrylic acid,acrylamide and Poly-SiO2 as monomers and N,N'-methylene diacrylamide as crosslinking agent.The obtained AA-Poly-SiO2 had an average size of 8.20μm and a specific surface area of 0.0725 m2/g.The structural characteristics of AA-Poly-SiO2 were analyzed by Fourier transform infrared spectroscopy(FTIR),thermo gravimetric analysis(TGA),scanning electron microscopy and X-ray powder diffraction.The adsorption properties of AA-Poly-SiO2 on nitrogen-containing cationic dyes methylene blue(MB),basic fuchsin(AM),methyl violet(MV)and ethyl violet(EV)were investigated.The effect of the adsorption time,pH,the amount of the agent and the initial concentration on the adsorption of the dye were studied,and the adsorption kinetics and isothermal adsorption process were also investigated.The results showed that its isothermal adsorption conformed to the Langmuir model,and the adsorption process followed the Langmuir isothermal adsorption and quasi-second-order kinetic model,indicating a single-layer adsorption.The maximum adsorption capacity of AA-Poly-SiO2 on ethyl violet was up to 1000mg/g.Compared with conventional polyacrylamide microspheres,AA-Poly-SiO2 showed higher adsorption capacity and could be recycled 5 times with an adsorption rate over 78%.