柠檬酸对高岭石中铝、硅释放的影响

Effect of Citric Acid on Aluminum and Silicon Release from Kaolinite

采用间歇法(batch method)模拟研究柠檬酸对水淋洗下高岭石铝、硅释放的影响.结果表明:柠檬酸能显著促进高岭石Al和Si的释放,且Al、Si的释放能力随柠檬酸浓度的增加而增强;高岭石溶解同步性与柠檬酸浓度有关,随着柠檬酸浓度的提高,其溶解的同步性增强,且反应前期高岭石都表现为Al的优先释放,而在反应后期Al、Si趋于同步释放.柠檬酸对高岭石的溶解速率一般较无机酸高1个数量级左右,且其溶解速率表现出对柠檬酸浓度的饱合性.

The experiments was conducted to investigate the effect of citric acid on aluminum and silicon release from water-eluviated kaolinite with batch method. The results showed citric acids enhanced significantly both Al and Si release from kaolinite, and release of Al and Si from kaolinite increase with concentration of citric acids compared with deionised water. Dissolution stoichiometry of kaolinite was related to concentration of citric acids, dissolution stoichiometry of kaolinite increase with concentration of citric acids, and preferential Al-release was observed initially but after reaction anaphase, Al and Si showed stoichiometric release. The rate of kaolinite dissolution obtained in citric acid solution was almost 1 order of magnitude as large as that of inorganic acid, and the dissolution rate behave the character of saturation with the concentration of citric acids.