纳米片多面体锰基锂离子筛的制备及锂离子吸脱附特性

Preparation of nano⁃flake polyhedral manganese based lithium ion sieve and its adsorption and desorption characteristic for Li+

针对锰基锂离子筛容量发挥不充分、使用寿命短的问题,以电解二氧化锰、氯化锂及无水氯化铝为原料,采用水热法合成了铝原子掺杂锰基离子筛前驱体,经酸洗脱附锂离子后得到锰基锂离子筛H_(1.6)(Mn_(1-x)Alx)_(1.6)O_(4)。扫描电镜结果表明,铝原子掺杂后,样品呈均匀光滑的纳米片多面体形貌,进一步的吸脱附等温线分析显示,样品的比表面积显著提高。锂离子吸脱附特性研究结果表明,Li_(1.6)(Mn_(0.7)Al_(0.3))_(1.6)O_(4)具有最佳的吸附提锂性能,锂离子溶液初始质量浓度为80 mg/L时,吸附容量为32.32 mg/L,5次循环提锂后,锂离子吸附容量可保持为初始吸附容量的95%。这些结果表明,结晶性好、比表面积大的纳米多面体锰基锂离子筛,吸附容量大、结构稳定性好,可为当前盐湖卤水中锂资源的开发和工艺优化提供技术参考。

Aiming at the problems of insufficient capacity and short service life for manganese⁃based lithium ion sieve,elec⁃trolytic manganese dioxide,lithium chloride and anhydrous aluminum chloride were used as raw materials to prepare Al doped manganese⁃based lithium ion sieve precursor through hydrothermal method.The manganese⁃based lithium ion sieve H_(1.6)(Mn_(1-x)Alx)_(1.6)O_(4) was obtained after acid extraction of Li^(+).SEM results indicated that a uniform and smooth nanosheet polyhedron morphology was obtained for the Al doped specimen.BET analysis further showed that the specific surface area was increased significantly.The results of the Li^(+) adsorption and desorption performance showed that Li_(1.6)(Mn_(0.7)Al_(0.3))_(1.6)O_(4) owned the best property.The equilibrium adsorption capacity was 32.32 mg/L when the initial concentration for Li^(+)solution was 80 mg/L,and after 5 cycles,the Li^(+) adsorption capacity could be maintained at 95%of the initial adsorption capacity.These results showed that with good crystallinity and large specific surface area,the nano⁃flake polyhedral manganese based lithium ion sieve possessed large adsorption capacity and good structure stability,which could provide a technical reference in the exploitation and process improvement of extracting lithium resources form salt⁃lake brine.