【摘要】 以十六烷基三甲基溴化铵为模板剂,水玻璃为硅源,采用水热法合成了中孔分子筛MCM-41。用X射线衍射分析、比表面积及孔径分布测试、透射电镜分析等手段对合成样品进行了表征。通过静态吸附实验,研究了MCM-41对水溶液中Cr(Ⅵ)离子的吸附动力学性质。结果表明:合成的中孔分子筛的孔径非常均匀,其孔道尺寸主要集中在2～4nm范围,平均孔径为3.64nm,比表面积为1047m2/g。Langmuir吸附等温式的曲线拟合能较好地描述不同温度下的实验数据,常温下分子筛对Cr(Ⅵ)离子的饱和吸附量为84.81mg/g。吸附符合一级动力学吸附方程,颗粒内扩散与吸附过程是影响吸附速率的主要控制步骤,在25,40℃和55℃下,吸附速率常数k分别为0.2121,0.2167min-1和0.2287min-1。更多还原

【Abstract】 An MCM-41 mesoporous sieve was synthesized by the hydrothermal method with sodium silicate as the silica source and surfactant hexadecyltrimethyl ammonium bromide(CTAB)as the structure template in basic media.The MCM-41 was characterized by X-ray diffraction,transmission electron microscope,specific surface area and pore distribution test.The adsorption kinetics of Cr(Ⅵ)ions adsorbed by MCM-41 in aqueous solution was studied through static experiments.The results show that the structure of the MCM-41 molecular sieve is uniformly arranged channels.The pore diameter of the molecular sieve is mainly in the range of 2 nm to 4 nm,and its average value is 3.64 nm.The specific surface area of MCM-41 is 1 047 m2/g.The adsorp-tion data fits well into the Langmuir adsorption isotherm.The capacity of the MCM-41 sieve to adsorb Cr(Ⅵ)ions is 84.81 mg/g at 25 ℃.The rate of adsorption of the solute follows first-order kinetics equation;intraparticle diffusion and adsorption is the main rate controlling step.The first-order kinetics rate constant k is 0.212 1,0.216 7 min-1 and 0.228 7 min-1 at 25,40 ℃ and 55 ℃,respectively.更多还原