Al13形态的分离纯化与表征

采用乙醇－丙酮沉淀法提取了聚合氰化铝（PAC）中的Al13形态并采用Al-Ferron逐时络合比色法、27Al NMR，SEM，TEM和XRD等方法对所获得的水溶性Al13形态进行了分析表征．结果表明，通过向聚合氯化铝溶液中不断加入乙醇和丙酮，聚合氯化铝中各形态组分便会按照在混合溶剂中溶解度由小到大的顺序，依次从溶液中析出．截取中间组分得到Al13 形态．Al-Ferron逐时络合比色法和27Al NMR的鉴定结果表明，采用该方法分离提纯得到的样品中Al13 的含量达95％以上．SEM和TEM的鉴定结果表明，固体Al13聚集体主要为棱柱、单斜长方体和四面体等多面晶粒，小的聚集体粒径约 200mm，大的可达 2μm．溶液中的Al13 形态聚集成束并以枝状排列．XRD结果表明，Al13的特征衍射峰出现在2θ为5°～25°的范围内．

Purification and Characterization of Al13 Species

Abstract The polynuclear Keggin species, AlC4Al12(OH)24(H2O)7+12(Al13) , was firstly separated and purified from polyaluminum chloride (P AC) by the precipitation method, which involved adding ethanol and acetone continuously to the PAC solution. The solid Alu obtained with excellent dissolubility was characterized by Al-Ferron timed complexation spectrophotometry, 27A1 NMR spectroscopy, SEM, TEM and XRD. The results show that the components of PAC would be separated out in soluble sequence from low to high when ethanol and acetone were added continuously to the PAC solution, and that Al with a high purity would be obtained by taking out the middle precipitate. From Al-Ferron timed complexation spectrophotometry and 27A1 NMR spectroscopy, it was found that the sample obtained contained more than 95% of Ali3. The SEM and TEM results showed that the small Ali3 aggregates were about 200 nm and the big one were about 2 um in diameter. The Aln aggregates were mainly polyhedron such as prism, monoclinic rectangle and tetrahedron in solid sample and showed a branch type in solution. In the XRD spectra, the signal of Al13 appeared in the range of 20 from 5?to 25?