富锂锂锰氧化物的制备及其在溶液中的抽Li^+/吸Li^+性能

Preparation and Li^+ Extraction/Adsorption Properties of Lithium-Rich Manganese Oxide in Aqueous Solution

采用柠檬酸配合法合成了系列尖晶石富锂锂锰氧化物Li2O.nMnO2(n=1.75,2.0,2.25,2.5,3.0)。通过X射线衍射(XRD)和酸浸实验发现,350℃合成的Li2O.2.25MnO2具有纯相尖晶石锂锰氧化物结构,且在弱酸性介质中具有较高的锂溶出率和较低的锰溶损率。Li2O.2.25MnO2在酸浸之后转型为锂离子筛。XRD和扫描电子显微镜(SEM)分析发现锂离子筛能够保持尖晶石锂锰氧化物的结构和形貌。吸附实验表明,该锂离子筛在碱性含锂溶液中对Li+具有吸附性能,且吸附容量随着溶液温度和pH值的升高而增大,最高能达到40.14 mg.g-1。通过傅立叶红外光谱(FTIR)研究了锂离子筛的吸附机理,并用Langmuir模型描述了其在LiCl+LiOH溶液中的吸附行为。

Spinel lithium-rich manganese oxides of Li2O·nMnO2（n=1.75,2.0,2.25,2.5,3.0） were synthesized via citric acid complex method.The results of XRD analysis and acid treatment reveal that Li2O·2.25MnO2 prepared at 350 ℃ consists of pure spinel phase of lithium manganese oxide and exhibits high Li extraction ratio and low Mn dissolution ratio.After acid treatment Li2O·2.25MnO2 is transformed to lithium ion-sieve.XRD and SEM analyses show that lithium ion-sieve can maintain the spinel structure and morphology of lithium manganese oxide.The Li＋ adsorption experiments show that lithium ion-sieve can adsorb Li＋ in alkaline solution and the Li＋ adsorption capacities increase with the increase of temperature and pH value of the solution.The maximum Li＋ adsorption capacity can reach 40.14 mg·g-1.The Li＋ adsorption mechanism was suggested based on FTIR spectroscopy results and the Li＋ adsorption behavior was modeled by Langmuir isotherm.