摘要
使用硝酸溶液对高温固相合成的Rb8Nb22O59进行酸洗脱铷离子,制备了离子筛吸附剂H8Nb22O59·8H2O。借助X射线衍射（XRD）、热重分析（TG-DSC）、扫描电镜（SEM）,分别对Rb8Nb22O59和H8Nb22O59·8H2O进行表征。详细考察了吸附剂对钠离子、钾离子的交换性能,筛选出制备吸附剂前驱体Rb8Nb22O59的最优条件,即将五氧化二铌和碳酸铷混合后在1200℃焙烧12h。研究结果表明：在1200℃焙烧12h制备的前驱体Rb8Nb22O59与其酸洗后的离子筛H8Nb22O59·8H2O具有相似的结构,前驱体铷离子的酸洗洗脱率可达97%左右,而铌的溶损率极低,小于0.04%,具有很好的再生利用特性;在高浓度氯化钠溶液中（钠与钾物质的量比为500∶1）考察了H8Nb22O59·8H2O对钠离子和钾离子的吸附特性,在pH为2-8内,相对于钠离子,吸附剂H8Nb22O59·8H2O对钾离子具有较高的分配系数,分离因数高达43。焙烧时间6h以上制备的前驱体Rb8Nb22O59,其酸洗后的离子筛H8Nb22O59·8H2O对钠离子和钾离子的分离因数基本不变。
The ionic sieve adsorbent RbsNb=O59-8H20 was prepared by extracting Rb＋from precursor RbsNb=O59,which was synthesized by solid state reaction at high temperature, in HNO3 solution.As-prepared Rb8Nb22O59· 8H20 and Rb8Nb22O59 were characterized by XRD, TG-DSC, and SEM.The exchange capacity of adsorbent for Na＋ and K＋ was investigated and the opti- mal preparation conditions for precursor RbsNb=O59 were proposed as well： calcinating the mixture of Rb℃03 and Nb205 at 1 200 ℃ for 12 h.Resuhs indicated that the structure of precursor Rb8Nb22O59 under above conditions was similar to that of prepared adsorbent Rb8Nb22O59·8H20 after acid treatment.Around 97% of Rb＋ of precursor could be extracted by acid elution, while the lost amount of niobium ions was negligible （less than 0.04% ）, showing a good capability of regeneration.In addition,the absorption capacity of Rb8Nb22O59· 8H20 for K＋ and Na＋ was evaluated in high concentrated sodium chloride solution （amount-of-substance ratio of Na＋ to K＋ was 500：1 ）.The adsorbent Rb8Nb22O59·8H20 had a higher distribution co- efficient for K＋ with separation factor of 43 rather than for Na＋ at pH ranging from 2 to 8.Meanwhile,it was found that distribution coefficients of Rb8Nb22O59· 8H20 for Na6 and K6 were stable when calcination time reached over 6 h.
出处
《无机盐工业》
CAS
北大核心
2015年第6期34-38,共5页
Inorganic Chemicals Industry
基金
天津市塘沽科委专项基金(No.09tgkw-12)资助
