纳米MnO2离子筛的锂吸附性能

通过控制水热合成反应条件制备了不同晶相的一维纳米MnO₂，进一步用浸渍法制备了Li-Mn-O三元氧化物前驱体，并经酸处理后得到对锂离子具有特殊选择性的离子筛。用XRD、TEM、吸附等温线及反应动力学等手段对产物的晶相结构和锂吸附性能进行了研究。实验结果表明，反应物浓度对MnO₂不同晶面的生长速率有不同的影响；从TEM图像中可以清楚地看到，水热合成法制备出了尺寸为φ5nm×400nm的一维MnO₂纳米线；在pH＝9.19时每克离子筛的单分子层锂离子饱和吸附量Q_m为2.43mmol·g^-1；吸附速率常数为2.17×10^-6 s^-1；吸附量随溶液pH值的增加而增加，当pH=12.5时，相应的吸附量为3.47mmol·g^-1。

Lithium adsorption on nanocrystalline MnO2 ion sieve

Various polymorphs of MnO₂ were synthesized with a controlled hydrothermal method.Li-Mn-O precursor was prepared by the wet impregnation of a solution of LiOH·H₂O into MnO₂ synthesized，and the final MnO₂ ion-sieve was obtained by acid treatment.The crystalline phase structure and exchangeability of Li⁺were studied with XRD，TEM Li⁺adsorptive isotherm and kinetic measurement.The result showed that reactant concentration had different effects on the growth rate of different MnO^₂ crystal faces.The novel MnO₂ nanowires，mainly about φ 5 nm×400 nm in diameter and length，were found to have a remarkable lithium ion sieve property with monolayer saturation amount of 2.43 mmol·g^-1 and the adsorption rate constant of 2.16×10^-6s^-1 at pH=9.19.The lithium adsorption capacity of MnO₂ ion-sieve increased with the increase of pH value，up to 3.47 mmol·g^-1 at pH=12.5.