摘要
采用间歇法模拟研究醋酸-醋酸铵缓冲体系中草酸对高岭石的溶解特征,以了解低分子量有机酸溶解高岭石时,其质子和配体的相对贡献。试验表明:反应液中Al、Si浓度随草酸浓度提高、反应液pH降低及反应时间的推移而增加,当草酸浓度为10 mmol/L,反应液pH为3.5,反应1 656 h后Al、Si的浓度达到最高,分别为2.27和1.86 mmol/L;且配体(RL)促进速率随着反应液酸度的增强而升高;低浓度草酸(1 mmol/L)时,增幅随pH的降低而大幅增加,高浓度草酸(≥5 mmol/L)时,随着酸度的升高,增幅大幅减弱;相对于质子对高岭石的溶解作用,本试验浓度及酸度范围内,配体对高岭石溶解的贡献是主要的。
To investigate the dissolution character of kaolinite induced by oxalic acids in HAc-NH4OAc buffer solution,and the relative contribution of proton and ligand with batch method.The concentration of Al and Si from kaolinite increased with concentration of oxalic acids and acidity of reactive solution and process of reactive time.When the concentration of oxalic acid was 10 mmol/L,acidity of reactive solution was 3.5,after reaction 1656 hours,the concentration of Al and Si reached a maximum,they were 2.27 and 1.86 mmol/L respectively;Ligand-promoted kaolinite dissolution rates(RL)improved with the acidity enhancement;The amplitude of Ligand-promoted kaolinite dissolution evidently improved with the acidity enhancement when the concentration of oxalic acids didn't exceed 1 mmol/L,but the amplitude evidently weaken when the concentration of oxalic acids wasn't less than 5 mmol/L.As far as the contribution of proton-promoted kaolinite dissolution was concerned,the contribution of Ligand-promoted kaolinite dissolution was primary in the range of concentration and acidity of oxalic acids in the experimentation.
出处
《中国土壤与肥料》
CAS
CSCD
北大核心
2012年第6期83-87,共5页
Soil and Fertilizer Sciences in China
基金
国家自然科学基金(40371067)
中国科学院知识创新工程项目(KZCX3-SW-417和ISSASIP0208)
关键词
高岭石
草酸
配体
质子
kaolinite
oxalic acid
ligand
proton