二氧化锰型钾离子筛的合成及其对钾的离子交换热力学  

Synthesis of cryptomelane-type hydrous manganese dioxide and its ion exchange thermodynamics for K^+

作　　者：董殿权[1] 刘维娜[1] 刘亦凡[1] 

机构地区：[1]青岛科技大学化工学院,山东青岛266042

出　　处：《化工进展》2009年第6期1005-1009,共5页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(29374625);山东省中青年科学家科研奖励基金(博士基金2008BS09004);青岛科技大学引进人才项目(0022322)资助

摘　　要：以硫酸锰和高锰酸钾为原料合成隐钾锰型水合二氧化锰(CRYMO),酸改型后得晶体结构为α-MnO2的钾离子筛(CRYMO-H)。CRYMO-H对K+的饱和交换容量达到4.6429mmol(181.54mg)K+/g离子筛,对钾离子有较高的表观交换容量。测定了15、25、35、45℃下CRYMO-H对H+-K+体系的离子交换等温线,采用Pitzer电解质溶液理论计算出该离子交换体系的活度系数,得到H+-K+交换的平衡常数KaKH、ΔrGmθ、ΔrHmθ和ΔrSmθ等热力学函数。结果表明:KaKH随温度的升高而降低、CRYMO-H对K+的选择性大于原来可交换阳离子H+的选择性、吸附钾的过程是自发过程(ΔrGmθ<0),该离子交换反应是放热反应。Cryptomelane-type hydrous manganese dioxide （CRYMO） was prepared by using manganese sulfate and potassium permanganate as raw materials. Potassium ion-sieve （CRYMO-H） with a crystal structure of α-MnO2 was obtained by acid-modification of CRYMO. CRYMO-H showed a high saturated ion-exchange capacity for K^＋ as measured as 4.6429mmol （181.54mg） K^＋/g ion-sieve in 0.1mol/L K^＋ solution. The exchange isothermal curves of H^＋-K^＋ on CRYMO-H were measured at 15 ℃, 25℃, 35℃, 45℃ respectively. The activity coefficients were calculated by using Pitzer electrolyte solution theory, other thermodynamic constant such as equilibrium constant KaH^K, ΔrGm^θ、ΔrHm^θ and ΔrSm^θ during the exchange process were obtained. The equilibrium constant reduced with increasing temperature, the selectivity of CRYMO for K^＋ was higher than the original ion （H^＋）, the exchange process was exothermic and spontaneous（ΔrGm^θ〈0）.

关 键 词：隐钾锰型水合二氧化锰 钾离子筛 热力学 Pitzer电解质溶液理论 

分 类 号：O614.111[理学—无机化学] TQ425.221[理学—化学]