膦酰基羧酸对碳酸钙的阻垢机理

通过透射电镜、扫描电镜和X射线衍射仪分析了投加膦酰基羧酸（POCA）对碳酸钙形貌及晶格参数2θ的影响，发现投加POCA改变了CaCO₃垢的结晶习惯并对方解石有一定的晶格扭曲作用，随着加药量的增加，方解石的比例减少，而文石和球霰石的比例增加，POCA对方解石（110）晶面的抑制作用强于（104）晶面;同时采用分子动力学(MD)方法，模拟计算了POCA与方解石的(110)、（104）晶面的相互作用， 结果表明：聚合物分子与晶面之间的结合能主要由Coulomb作用和van der Waals作用力提供。比较POCA在方解石两晶面上的结合能，发现E_bind(110)大于E_bind(104)，两者数值之比约为1.39，即POCA分子与(110)面的结合比(104)面更牢固，说明POCA对(110)面生长的抑制居于主导地位。两种研究方法得到的结论一致。

Scale-inhibiting mechanism of phosphono carboxylic acid on CaCO3

The changes of configuration and lattice parameter of CaCO3 induced by phosphono carboxylic acid (POCA) were studied by using TEM, SEM and XRD.It was confirmed that POCA could change the crystallizing habit of CaCO3 and cause twist of calcite.The higher the concentration of POCA, the smaller the ratio of calcite and the greater the ratio of aragonite and vaterite .The inhibition of POCA on (110) crystal surface was stronger than that on (104).On the other hand, the interactions between POCA and (110) and (104) crystal surfaces of calcite crystal were simulated by molecular dynamics (MD).The analysis of various interactions of all systems indicated that the binding energies were mainly provided by Coulomb interaction and van der Waals interaction.The binding energies between POCA with (110) and (104) crystal surfaces were compared, and it was found Ebind(110) was greater than Ebind(104) and the ratio was about 1.39, that is to say the combining of POCA with (110) crystal surface was more firmly than that with (104), and so the scale-inhibition of POCA on the growth of (110) crystal surface was dominant.The results of two study methods were consistent.