聚合氯化铝中纳米Al13形态的分离纯化及形态表征

采用超滤法和层析法分离纯化聚合氯化铝(PAC)中的Al₁₃形态,并采用Al-Ferron逐时络合比色法、²⁷Al-NMR、TEM和粒度测定仪对分离纯化所得的Al₁₃形态进行了分析和表征.研究结果表明,超滤法分离纯化的效果受超滤膜的孔径及PAC浓度的影响,选择合适孔径的膜和PAC溶液浓度即可以获得高纯度的Al₁₃,在层析法中则随着洗脱时间延长按分子的大小依次洗脱下来,因此截取中间组分即可得到Al₁₃;Al-Ferron逐时络合比色法和²⁷Al-NMR的分析结果表明,采用上述2种方法分离提纯得到的样品中Al₁₃的含量分别可达到90%以上和100%.TEM和粒度测定结果表明,在B=2.5的PAC溶液中,Al₁₃极少以Al₁₂AlO₄(OH)₂₄(H₂O)⁷⁺₁₂的单体形态存在,而是呈两维结构的线性和枝状的聚集体,Al₁₂AlO₄(OH)₂₄(H₂O)⁷⁺₁₂的聚集体尺寸通常在几十至几百nm.

Purification and Characterization of Nano Al13 Species in Polyaluminum Chloride

The polynuclear Keggin species, Al₁₂AlO₄(OH)₂₄(H₂O)⁷⁺₁₂ (Al 13 ), was firstly separated and purified from polyaluminum chloride (PAC) by the ultra filtration and column chromatography method. The Al₁₃ yield was characterized by Al Ferron timed complexation spectrophotometry, ²⁷Al-NMR,TEM and ZATESIZER 3000HSA.The results showed that the purified sample by the ultra filtration method influenced by membrane pore radius and the concentration of PAC solution. High purity Al₁₃ would be obtained by choosing appropriate membrane and concentration of PAC. When using the column chromatography method, the bigger molecules were eluated first, then the smaller ones. Al₁₃ would be obtained by taking out the middle educt. From Al Ferron timed complexation spectrophotometry, it was found that the obtained sample contained more than 90% and 100% of Al₁₃ by using the two methods mentioned above respectively. The TEM and ZATESIZER 3000HSA results showed that Al₁₃ was mainly aggregated as line type and branch type in B=2.5 solution, and the size was about several decade and several hundred nm.