水蒸气对高岭土高温吸附铅的影响

Effect of water vapor on lead adsorption by kaolinite at high temperatures

摘要: 使用沉降炉开展了水蒸气对高岭土高温吸附铅影响的实验研究，其中铅的形态为PbO和PbCl₂两种。首先研究了0-20%水蒸气对高岭土吸附PbO（1100-1300 ℃）和PbCl₂（800-1300 ℃）的影响规律，然后基于XRD、SEM和残余羟基率等分析，掌握了水蒸气影响高岭土高温吸附的机理。结果表明，水蒸气可以减少高岭土表面羟基的高温脱落，从而阻碍了PbO吸附、促进了PbCl₂吸附。综合高温下惰性莫来石的出现和高岭土孔隙结构的坍塌等因素，PbO和PbCl₂的最佳吸附温度分别为1200和1000 ℃。

Abstract: The effect of water vapor on lead adsorption by kaolinite at high temperatures was studied using a drop tube furnace. The lead was in the forms of PbO and PbCl₂. Firstly, effect of 0-20% water vapor was studied on adsorption of PbO (1100-1300 ℃) and PbCl₂ (800-1300 ℃) by kaolinite. Then, mechanism of high-temperature adsorption of kaolin was revealed according to the analysis of XRD, SEM and residual hydroxyl group fraction. The results showed that water vapor reduced the loss of hydroxyl groups on kaolinite surface at high temperatures, hindering PbO adsorption and promoting PbCl₂ adsorption. At the same time, due to production of inert mullite and collapse of pore structure of kaolinite at high temperatures, the optimal adsorption temperatures of PbO and PbCl₂ were 1200 and 1000 ℃, respectively.