起泡剂在气液界面的吸附结构的DFT研究（英文）

Adsorption structures of frothers at gas–liquid interface using DFT method

采用密度泛函理论(DFT)模拟研究了起泡剂与气泡气液界面之间的吸附机理。在水相中,起泡剂分子的极性基团通过氢键与水分子连接,而非极性基团表现出疏水性并且排斥开其周围的水分子。水分子在单一起泡分子上的吸附现象表明,α-萜烯醇与7个水分子,MIBC与7个水分子,DF200与13个水分子的配合物分别达到了他们的稳定结构。水化层同时影响极性基团和非极性基团。DF200的液膜排液速率最慢,而α-萜烯醇和MIBC几乎相同。吸附在气–液界面处的起泡剂分子的吸附层显示α-萜烯醇分子排列整齐、分布更好,而DF200分子的排列比MIBC分子更加松散,这表明,与DF200和MIBC相比,α-萜烯醇分子层可以更好地阻止气体通过液膜扩散。模拟结果表明,α-松油醇的泡沫稳定性最好,其次是DF200和MIBC。

Density functional theory (DFT) simulation was performed to investigate the adsorption mechanisms between frothers and gas–liquid interface. In water phase, the polar head group of the frother molecule was connected with water molecules by hydrogen bonding, while the non-polar group showed that hydrophobic property and water molecules around it were repelled away. The adsorption of water molecules on single frother molecule suggests that the complexes of α-terpineol-7H2O, MIBC-7H2O and DF200-13H2O reach their stable structure. The hydration shell affects both the polar head group and the non-polar group. The liquid film drainage rate of DF200 is the lowest, while α-terpineol and MIBC are almost the same. The adsorption layer of frother molecules adsorbed at the gas-liquid interface reveals that the α-terpineol molecules are more neatly arranged and better distributed. The DF200 molecules are arranged much more loosely than MIBC molecules. These results suggest that the α-terpineol molecule layer could better block the diffusion of gas through the liquid film than DF200 and MIBC. The simulation results indicate that the foam stability of α-terpineol is the best, followed by DF200 and MIBC.