膦系阻垢剂对碳酸钙阻垢机理的研究

Study of the Mechanism of Phosphonate Scale Inhibitors againist Calcium Carbonate Scale

在模拟循环水中,通过静态阻垢实验研究了HEDP,PBTCA,ATMP和EDTMP对碳酸钙的阻垢性能,在相同的加药浓度下(按物质的量浓度计)阻垢性能的强弱顺序为HEDP>PBTCA>ATMP>EDTMP;同时采用分子动力学方法,模拟计算了阻垢剂负二价离子与方解石(104),(102),(202)和(113)面的相互作用.结果表明:阻垢剂分子中的膦酸基团和羧酸基团与碳酸钙中的Ca2+形成的离子键对吸附起到了主要作用,同时阻垢剂与晶面间存在较弱的范德华力相互作用.阻垢剂与各晶面的结合能强弱顺序为(113)≥(102)≥(202)>(104);分子中的羟基易与垢晶面形成氢键而加强阻垢效果;羧基的位置不同对阻垢作用的影响不同.将静态阻垢的实验结果与分子动力学模拟结果进行了相关性分析,发现阻垢剂在(104)面和(102)面上的吸附对阻垢作用的贡献较大.

The scale inhibition ability of HEDP,PBTCA,ATMP and EDTMP was investigated through the static scale inhibition experiments in simulated circulating water,as a function of inhibitor concentration.The results allow us to give the following order of inhibitor effectiveness：HEDPPBTCAATMP EDTMP.Meanwhile,molecular dynamic simulations of the interactions of the negatively divalent ion of phosphonates with calcite surfaces（104）,（102）,（202） and（113） indicate that ion bonds between the phosphonate functional groups or carboxylic acid groups of inhibitors and the Ca2＋ of calcite play the dominant role in their adsorption,and weak vdW interaction also exists.The binding energy has the sequence of（113） ≥（102）≥（202）（104）,the scaling inhibition effect is enhanced by hydrogen bond formed between hydroxyl group of scale inhibitor and the crystal surface,and the different sites of carboxyl groups result in different influence on scale inhibition.The analysis of correlation of scale inhibition results with molecular dynamic simulations suggests that the adsorption of inhibitors on the surface（104） and（102） be central.