摘要
以碳酸锰和甲醇钾为原料,采用高温固相法制备出隐钾锰型二氧化锰(CRYMO),进一步酸洗后得到钾离子筛(CRYMO-H)。利用AAS、TG-DTA、BET、XRD、SEM,对样品组成和结构进行了表征,考察了原料配比、焙烧温度、焙烧时间对样品晶相的影响,测定了CRYMO-H对钾、钙、镁、钠、锂单盐离子溶液的交换容量和对海水中主要阳离子的选择性。结果表明,原料Mn/K摩尔配比为4∶1、焙烧温度为620℃、焙烧时间为12h时,合成样品化学组成为K0.95Mn7.96O16.00,晶相为α-MnO2,650℃以下相对较稳定,呈现棒状外形,比表面积为37.33m2/g;样品对纯氯化钾溶液和海水中钾离子的交换量分别达126.78和29.11mg/g;样品对K+/Na+、K+/Li+溶液中K+的选择性系数分别为115.68和134.91,对Ca2+、Mg2+则没有交换量,可用于从海水中选择性分离钾盐。
Cryptomelane-type manganese dioxide was prepared using manganese carbonate and potassium methoxide as the raw materials by high temperature solid-state method.A novel potassium ion-sieve（CRYMO-H） was obtained by acid-modification of CRYMO.The characterizations of the synthesized CRYMO-H were carried out by AAS,TG-DTA,BET,XRD and SEM.The effects of the Mn/K ratios of raw materials,calcined temperature and calcined time on crystal phase were investigated.The exchange capacities to K^＋,Ca^2＋,Mg^2＋,Na^＋,Li＋ in single salt solution and the selectivities of CRYMO-H for the main cations in the seawater were measured.The results show that the chemical formula of the sample is K0.95Mn7.96O16.00 and its crystal phase belongs toα-MnO2 when prepared at the Mn/K ratio of 4：1,calcined temperature of 620℃ and calcined time of 12h.The sample is stable up to 650℃ and its morphology is virgulate-like.The exchange capacities of CRYMO-H to K^＋ in pure potassium solution and seawater are 126.78 and 29.11mg/g respectively,and its selectivity coefficients to K^＋in the solution of K^＋/Na^＋ and K^＋/Li＋ are 115.68and 134.91 respectively,whereas it has no exchange capacity for Ca^2＋and Mg^2＋.Therefore,the ion-sieve can be used to extract potash selectively from seawater.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2010年第11期1989-1993,共5页
Journal of Functional Materials
基金
"十一五"国家科技支撑计划重大资助项目(2006BAB03A10)
山东省自然科学基金资助项目(ZR2009BM002)
关键词
高温固相法
隐钾锰型二氧化锰
钾离子筛
离子交换性能
high temperature solid-state method
cryptomelane-type manganese dioxide
ionic sieve for potassium
ion exchange performance
