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: HEDP＞PBTCA＞ATMP＞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 Ca^2＋ 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.

Key words: phosphonate scale inhibitor, static scale inhibition, molecular dynamic simulation, linear regression