Al-Mn柱撑蒙脱石的制备和微结构变化研究

PREPARATION AND MICROSTRUCTURE OF Al-Mn-PILLARED INTERLAYER MONTMORILLONITE

以辽宁某地的钙基膨润土为原料 ,首先对其钠化改型得到适合制备柱撑蒙脱石的基质 ,然后采用取代法合成Al-Mn柱化剂 ,依此制备了Al-Mn柱撑蒙脱石 ,并运用X射线衍射分析、化学分析、红外光谱分析及煅烧试验等手段研究了Al-Mn柱撑蒙脱石的微结构变化和热稳定性 .结果表明 :n(Mn2 + )∶n(Al3 + )为 0 .5时 ,可得到层间距d( 0 0 1 ) 值为 1.8987nm的产物 ,30 0℃煅烧后其层间距稳定在 1.785 9nm ,具有较好的热稳定性 ;钠基膨润土经柱撑反应后 ,柱化剂进入了蒙脱石层间 ,同时蒙脱石骨架 [Si4O1 0 ] n 与层间柱化剂离子之间发生了成键反应 。

Pillared montmorillonites are a new family of materials obtained by using inorganic polyhydroxycations to form pillars between the layers of smectitic silicates. Al-Mn_pillared interlayer montmorillonite was prepared using Na-bentonite as starting materials. Pillaring agent solutions were prepared by adding 0.2 mol·L -1 MnCl 2 solution into the solution containing hydroxy-Al oligocations with x (OH -)∶ x (Al 3+ )=2.4. The microstructure and thermal stability of pillared interlayer clays were determined by XRD and FTIR, chemical analysis and calcination tests. The results indicate that, when n (Mn 2+ )∶ n (Al 3+ )=0.5, the d (001) value of the pillared interlayer montmorillonite obtained is 1.898 7 nm. After calcined at 300 ℃, the basal interlayer spacing with high thermal stability is 1.785 9 nm, and the hydroxy-Al-Mn oligocations are introduced into the montmorillonite through chemical bonds, i.e. Si-O-Al or Si-O-Mn.