有机膦酸阻垢剂与方解石晶体相互作用的DFT研究

Density functional theory study of interaction between calcite crystal and phosphonic acids

用周期性边界条件下的密度泛函方法,模拟计算了6种有机膦酸阻垢剂[氨基三亚甲基膦酸(ATMP)、甲胺二亚甲基膦酸(MADMP)、甘氨酸二亚甲基膦酸(GDMP)、乙二胺四亚甲基膦酸(EDTMP)、羟基亚乙基二膦酸(HEDP)、氨基亚乙基二膦酸(AEDP)|与方解石(104)晶面的相互作用。结果表明,有机膦酸分子与方解石(104)晶面的结合能排序为ATMP>EDTMP>HEDP>GDMP>AEDP>MADMP。电荷、亲核Fukui指数计算数据表明,膦羧基以及羧基上的氧原子供电子能力很强,与晶面Ca^(2+)之间存在强静电相互作用,是阻垢剂的活性中心。

The interactions between phosphonic acids, i.e. aminotrimethylene phosphonic acid （ATMP） , methylaminodimethylene phosphonic acid （MADMP） , glycin dimethylene phosphonic acid （C, DMP） , ethylenediaminetetramethylene phosphonic acid （EDT- MP） , 1-hydroxyethylidene-1,1 -diphosphonic acid （HEDP） , 1 -aminoethylidene-1,1 -diphosphonic acid （AEDP） and the （ 104 ） face of calcite crystal have been simulated by density functional theory under the periodic boundary condition. Results show that the order of binding energies of scale inhibitors with （104） face of calcite crystal is as follows： ATMP 〉 EDTMP 〉 HEDP 〉 C, DMP 〉 AEDP 〉 MADMP. The calculated data of charge distribution and nucleophilic Fukui index indicate that the oxygen atoms in phosphonate and carboxyl groups are powerful to donate electrons, strong electrostatic interaction occurs between them and the calcium ions of calcite crystal, so these are active centers of scale inhibitors.