The adsorption energy,adsorption equilibrium configuration and electron density difference of the molecular forms and ionic forms of methyl primary amine,secondary amine,tertiary amine and quaternary ammonium salt adsorbed on the(001)surface of montmorillonite were simulated by density functional theory(DFT).The transmittance of supernatant of montmorillonite suspension,adsorption amount of surfacant and surface contact angle were measured.The results showed that the adsorption energy of ionic forms of methyl amines on the surface of montmorillonite was much larger than that of molecular form,so the ionic forms could be adsorbed on the surface stably.The adsorption energies of methyl amines on montmorillonite surface was affected by the degree of substitution of methyl group for H atoms on N atom of alkylamine.The larger the degree of substitution,the smaller the adsorption energy,and the poorer the hydrophobicity modification ability of methyl amines for the montmorillonite surface.The methyl amines cations were adsorbed on montmorillonite mainly through electrostatic interaction and hydrogen bonding.The experimental results of the supernatant of the montmorillonite suspension,adsorption amount of surfactant and surface contact angle were consistent with the results of the simulation.%采用密度泛函理论方法计算了不同甲基取代程度的甲基胺类(伯胺、仲胺、叔胺和季铵)的分子形式和离子形式在蒙脱石(001)表面上的吸附能、吸附平衡构型和差分电子密度,并测试了药剂作用后蒙脱石悬浮液上清液透光率、表面对药剂的吸附量和表面接触角.结果表明:甲基胺类离子形式在蒙脱石表面的吸附能比分子形式的大很多,可以稳定吸附在表面上;烷基胺中N原子上的甲基对H原子的取代程度越高,吸附能越小,对蒙脱石表面的疏水改性能力越差;甲基胺类阳离子主要通过静电作用和氢键作用吸附到蒙脱石表面上;药剂作用后蒙脱石悬浮液的上清液透光率、表面对药剂吸附量和表面接触角的试验结果与模拟结果相一致.
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