十六烷基三甲基溴化铵改性X分子筛对铬酸盐的吸附平衡及动力学  

Adsorption equilibrium and kinetics of chromate in wastewater by hexadecyl trimethyl ammonium bromide modified X zeolite

作　　者：孙霞[1] 刘红慧[1] 韩照祥[1] 

机构地区：[1]淮海工学院环境工程系,江苏连云港222005

出　　处：《化学工程》2013年第4期25-28,共4页Chemical Engineering(China)

基　　金：重庆市高校微纳米材料工程与技术重点实验室开放课题(KFJJ1106)

摘　　要：用十六烷基三甲基溴化铵(HTAB)对X分子筛改性,考察改性分子筛对水中铬酸盐的吸附平衡及吸附动力学。采用XRD和FT-IR对样品进行表征,结果表明改性后HTAB-X分子筛在保持原有结构和形貌同时,接枝了一定量的长链季铵盐阳离子功能基团。吸附实验表明,0.7 g改性分子筛在25℃、pH=6条件下,去除率为94.14%,比X分子筛提高了近36%。HTAB-X分子筛对铬酸盐的吸附遵循Langmuir模型,最大吸附容量为16.33 mg/g。热力学和动力学分析表明,该吸附过程为自发的放热过程,适合在常温下进行;吸附过程遵循准二级动力学模型,平衡吸附容量qe,cal达到2.71 mg/g,速率常数k2为0.362 g/(mg·min)。X zeolite was modified by the surface active agent of hexadecyl trimethyl ammonium bromide （HTAB）. HTAB-X sample was characterized by X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FT- IR）. The results show that the modified zeolite keeps the original structure and morphology as well as grafting a certain amount of long chain quaternary ammonium salt cationic groups. HTAB-X was studied for adsorption of chromate in wastewater. The batch experiments show that with the dosage of modified zeolite 0.7 g, the removal efficiency of chromate by HTAB-X is 94.14% at 25 ℃ and pH = 6, increasing by 36% compared with X zeolite. The adsorption isotherm of chromate on HTAB-X fits to the Langmuir isotherm with a maximum adsorption capacity of 16.33 mg/g. The analysis of thermodynamics indicates that the adsorption is an exothermic spontaneous process occurring at room temperature. The results of the kinetics analysis present that the sorption process follows a pseudo-second-order kinetics, and the adsorption equilibrium capacity q 1 reaches 2.71 mg/g with the rate constant k2 of 0.362 g/（ mg ·min）.

关 键 词：HTAB 分子筛 改性 Cr(Ⅵ) 热力学 动力学 

分 类 号：O647.31[理学—物理化学]