中文摘要：

选取了常用水处理剂包括HEDP,HPAA,PBTCA,ATMP,EDTMP,BHMTPMPA,DTPMP,PAPEMP,HDTMP,PAA和HPMA,进行溶解碳酸钙垢和铁垢的筛选研究.结果表明,除PAA外其他水处理剂都能溶解碳酸钙垢,机理是其电离出的H＋离子溶解碳酸钙垢.而铁垢只有HEDP,HPAA能溶解,其他水处理剂即使浸泡2个月仍然不能溶解,机理是HEDP,HPAA和Fe3＋离子形成了稳定的螯合物.HEDP和HPAA具有与其他水处理剂不同的特殊结构：在中心C原子连有膦酸基团或羧酸基团,并且中心C原子连有1个重要的羟基.这种特殊结构具有溶解铁垢的能力,而其他的不能溶解铁垢的水处理剂都不具有这种结构.运用Gaussian09程序,采用了密度泛函的B3LYP方法,对Fe原子采用赝势基组LANL2DZ,对其他原子采用6-31＋g（d,p）基组,优化出HEDP,HPAA与Fe3＋离子形成的螯合物的分子结构并分析各基团所起的作用.膦酸基团、羧酸基团和羟基共同参与配位,与Fe3＋离子形成六配位八面体结构.从分子结构和NBO电荷分布角度探讨了HEDP比HPAA具有更强的溶解铁垢能力的原因.揭示了HEDP在水处理剂中最为常用于化学清洗行业的本质原因,为化学清洗分子设计奠定了基础.

英文摘要：

The common water treatment agents including HEDP,HPAA,ATMP,PBTCA,EDTMP,BHMTPMPA,DTPMP,PAPEMP,HDTMP,PAA and HPMA were screened to dissolve calcium carbonate scale and ferric scale.The results showed that water treatment agents outside PAA could dissolve calcium carbonate scale.The mechanism is that water treatment agents can ionize hydrogen ions and dissolve calcium carbonate scale by acidity.But only HEDP and HPAA could dissolve ferric scale.Other agents still can＇t dissolve ferric scale after two months.The mechanism is that HEDP,HPAA and Fe3＋can form a stable chelate.HEDP and HPAA have special structure different from other agents：the central C atom links phosphonic acid groups or carboxylic acid groups and a important hydroxyl group.This special structure has the ability to dissolve the ferric scale.Other agents which couldn＇t dissolve ferric scale don＇t have such a structure.The theoretical calculation was conducted by Gaussian09 using density functional theory（DFT）at B3LYP/LANL2 DZ level for iron atom and B3LYP/6-31＋g（d,p）level for other atoms.The chelate structures were optimized and the functions of every groups were analyzed.The phosphonic acid groups,carboxylic acid groups and hydroxyl group work together and coordinate with Fe3＋to form a six-coordinated chelate in octahedral geometry.The reason why the dissolution ability of HEDP is stronger than HPAA was explained from molecular structure and NBO charge distribution.This study conclusions revealed that HEDP in common water treatment agents was most commonly used for chemical cleaning and laid a foundation for molecular design of chemical cleaning.