尖晶石型锂离子筛的制备及其吸附性能  

Preparation and adsorption property of spinel-type lithium ion-sieve

作　　者：石西昌[1] 余亮良[1] 陈白珍[1] 张丽芬[1] 周定方[1] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2011年第8期2198-2203,共6页Journal of Central South University:Science and Technology

基　　金：国家"十一五"科技支撑计划项目(2008BAB35B04)

摘　　要：对尖晶石型锂离子筛前驱体LiMn2O4,用0.5 mol/L HCl进行酸洗脱锂,制得锂离子筛λ-MnO2,将离子筛在不同pH和不同Li+浓度的溶液中进行吸附,对吸附过程动力学进行研究,同时运用XRD和SEM对前驱体及离子筛吸附前后的样品进行相应表征。研究结果表明:锂离子筛吸附交换前后晶体结构只发生细微变化,但都保持了尖晶石结构;酸浸洗脱时间越长,对离子筛前驱体中Li+的洗脱率越高,但同时离子筛的溶损率加大,洗脱5 h锂的迁出率为97%,而锰的溶损率也达到15%;Li+交换容量随着pH升高而增大,在pH为12.95时,LiOH溶液中离子筛的平衡吸附容量为23.75 mg/g;吸附过程符合伪二级动力学方程和Langmuir等温吸附方程,表明吸附过程主要为化学吸附,对锂离子的吸附为单分子层吸附。Lithium ion-sieve of λ-MnO2 was prepared by leaching precursor LiMn2O4 in 0.5 mol/L HCl solution to remove Li＋,the Li＋ exchange capacity of Li＋ sieve at different pH values and its adsorption kinetics were studied,and some samples were also characterized by XRD and SEM.The results indicate that some nuances appear in the microstructure of the samples after adsorbing lithium ion,but it is still similar to LiMn2O4.The longer the time of elution,the higher the elution ratio of Li＋ on the adsorbent;simultaneously,the adsorbent dissolving ratio of manganese also increases.The extraction ratio of Li＋ from LiMn2O4 is 97% and the dissolving ratio of Mn2＋ is 15% after 5 h leaching.The exchange capacity of the ion-sieve is enhanced with the increase of pH in the process of adsorption and its balance adsorption capacity is 23.75 mg/g when pH is 12.95 in LiOH solution.The adsorption process is found to fit pseudo-second-order kinetic equation and the Langmuir isotherm equation,so the adsorption process is determined to be chemical adsorption and monolayer adsorption.

关 键 词：锂离子筛 洗脱 吸附 吸附动力学 等温吸附 

分 类 号：TQ131[化学工程—无机化工]