摘要
研究磷酸钛离子交换剂(Li-TiOP)在饱和LiNO_(3)溶液中对Cu^(2+)、Co^(2+)、Mn^(2+)、Ni^(2+)和Cr^(3+)离子的吸附性能。采用XRD、SEM、TG、DSC、NGSP和元素分析对固体样品进行表征。采用原子吸收光谱法(AAS)和电感耦合等离子体质谱法(ICP MS)测定溶液中离子的浓度。采用Langmuir、Freundlich、Temkin和Nikolsky模型计算金属离子的吸附等温线。在研究金属离子吸附时,必须考虑吸附剂的溶剂化状态。Li-TiOP对所研究离子的选择性为:Cr^(3+)>Cu^(2+)>Mn^(2+)>Co^(2+)>Ni^(2+),且对上述4种模型均适用。吸附过程热力学参数的变化与吸附剂离子电位的变化有关。磷酸钛能有效去除多组分溶液中的微量金属离子,使LiNO_(3)纯度高于99.999%(质量分数)。
Sorption properties of titanium phosphate ion-exchanger(Li-TiOP)towards Cu^(2+),Co^(2+),Mn^(2+),Ni^(2+)and Cr^(3+)ions in saturated LiNO_(3)solution were investigated.Solid samples were characterized by XRD,SEM,TG,DSC,NGSP and elemental analysis.Concentrations of elements in the solutions were determined by AAS and ICP MS methods.The adsorption isotherms for studied metal ions were calculated using the Langmuir,Freundlich,Temkin and Nikolsky models.Necessity for allowing for the solvated state of the sorbate is shown in studying the sorption of metal ions.Selectivity of Li-TiOP towards studied ions is found to be described in the following order of Cr^(3+)>Cu^(2+)>Mn^(2+)>Co^(2+)>Ni^(2+)for all models.The change in the thermodynamic parameters of the sorption process is associated with that in the ionic potential of the sorbent.Titanium phosphate effectively removes trace concentrations of metal ions from multi-component solutions,resulting in achievement of LiNO_(3) purity level of>99.999 wt.%.
关键词
硝酸锂
磷酸钛
提纯
过渡金属元素
吸附
吸附等温线
热力学
lithium nitrate
titanium phosphate
purification
transition metal elements
sorption
adsorption isotherm
thermodynamics
