Chemial Bond and Stability of Adsorption of [Au(AsS_3)]^(2-)on the Surface of Kaolinite

Density function theory and discrete variation method (DFT-DVM) were used to study the adsorption of [Au(AsS 3)] 2- on the surface of kaolinite.The correlation among structure,chemical bond and stability was discussed.Several models were selected with [Au(AsS 3)] 2- in different directions and sites.The results show that the models with gold on the edge of kaolinite basal layer contain pincerlike bond among gold and several oxygen atoms and form strong Au-O covalent bond,so these models are more stable than those with gold above or under the layer.The models with gold near to [AlO 2(OH) 4] octahedra are more stable than those with gold near to the vacancy without aluminium.These two stable tendencies in kaolinite-[Au(AsS 3)] 2- are stronger than that in kaolinite-Au systems.The interaction between [Au(AsS 3)] 2- and kaolinite is stronger than that between gold and kaolinite,and this interaction is strong enough to form the surface complexes.

微波制备高岭石-TMAH复合物对氰化物的吸附性能

用微波加热法制备了高岭石-TMAH(四甲基氢氧化铵)复合物,探索了制备的优化条件,并进行了含氰化物废水的吸附试验。结果表明,当微波输出功率为最大功率的60%,加热时间9 min时,微波合成的高岭石-TMAH复合物层间距为1.4322 nm,比原高岭石增加0.7125 nm;用此复合高岭石处理含氰化物质量浓度为0.021 mg·L-1的废水,在加入量为0.5 g·L-1,吸附反应时间25 min,溶液pH调节为6时,氰化物去除率达98.2%。