Abstract:

SA lithium ion sieve membrane was prepared by blend of the zirconium-coated lithium ion sieve precursor LMZO with sodium alginate (SA) and polyethylene glycol (PEG). A series of experiments for examining its adsorption and cycle stability were carried out, and the adsorption isotherm model and the adsorption kinetics were analyzed. The results showed that the adsorption capacity of SA lithium ion sieve membrane was 1202.17 mg·m^-2 when the concentration of SA was 30 mg·ml^-1, the content of PEG was 1%, and the amount of loading of LMZO was 55%. After treated with 0.1 mol·L^-1 HCl, the extraction of Li⁺ reached 66.55% and the dissolution loss rate of Mn²⁺ was only 0.345% in equilibrium. After 10 cycles of adsorption and desorption in brine, the Li⁺ adsorption capacity was lost only 7.0% (from 1198.40 mg·m^-2 to 1116.64 mg·m^-2). In brine containing a variety of complex ions such as Na⁺, K⁺, Mg²⁺ and Ca²⁺, the SA film-like lithium ion sieve has a high selectivity to Li⁺, and its adsorption process is more in line with the pseudo-second-order kinetic equation and the Langmuir adsorption isotherm model. It is potential to be used in enrichment and recovery of lithium from salt lake brine and other liquid lithium sources.

Key words: lithium ion sieve, sodium alginate, brine, absorption, membrane, separation

摘要：

采用亲水的SA为成膜材料，PEG为致孔剂，制备了掺杂自制锆氧化物包覆的锂离子筛前体LMZO的膜状锂离子筛，研究其对锂的吸附性能以及循环稳定性能等，并对其进行了吸附动力学及吸附等温模型分析。结果表明：SA浓度为30 mg·ml^-1，PEG含量为1%，LMZO含量为55%时，制得的膜状锂离子筛对Li⁺的吸附性能最好，为1202.17 mg·m^-2。用0.1 mol·L^-1 HCl溶液解吸，平衡时锂解吸率可达66.55%，锰溶损率仅为0.345%。在卤水中进行了10次循环吸附解吸后，吸附量降至1116.64 mg·m^-2，吸附量仅损失了7.0%。在含有多种复杂离子如Na⁺、K⁺、Mg²⁺和Ca²⁺的卤水中，SA膜状锂离子筛对Li⁺有很高的选择性，其吸附过程更符合伪二级动力学方程及Langmuir吸附等温模型。膜状锂离子筛对于从盐湖卤水等液态锂资源中提取锂具有很大的开发潜力。

关键词: 锂离子筛, 海藻酸钠, 盐湖卤水, 吸附, 膜, 分离