Jones Franca, Jones Phillip, Ogden Mark I, Richmond William R, Rohl Andrew L, Saunders Martin
A.J. Parker CRC for Integrated Hydrometallurgical Solutions, Nanochemistry Research Institute, Department of Applied Chemistry, Curtin University of Technology, GPO Box U1987, Perth WA 6845, Australia.
J Colloid Interface Sci. 2007 Dec 15;316(2):553-61. doi: 10.1016/j.jcis.2007.09.005. Epub 2007 Sep 8.
Ethylenediaminetetraacetic acid (EDTA) is a known complexing agent that interacts with a host of cations. In this paper, various techniques are used to elucidate the mechanism of interaction between EDTA and barium sulfate surfaces. It is shown that complexation with metal ions is not sufficient to explain the inhibition of barite crystallization but that other processes such as chemisorption must also occur. EDTA is shown to always adsorb as the mono-protonated species - suggesting that the molecule is able to lose a proton when it adsorbs at lower pH. Molecular modelling shows that the interaction of the surface barium ions with the carboxylate group is an important one. Finally, in situ turbidity measurements provide information about the mechanism of nucleation/growth modification. It is found that the EDTA molecule inhibits barium sulfate nucleation and that this could be its primary means of inhibiting precipitation of barium sulfate.
乙二胺四乙酸（EDTA）是一种已知的络合剂，可与多种阳离子相互作用。在本文中，采用了各种技术来阐明EDTA与硫酸钡表面之间的相互作用机制。结果表明，与金属离子的络合不足以解释重晶石结晶的抑制作用，还必须发生其他过程，如化学吸附。研究表明，EDTA总是以单质子化形式吸附，这表明该分子在较低pH值下吸附时能够失去一个质子。分子模型显示，表面钡离子与羧酸根基团的相互作用很重要。最后，原位浊度测量提供了有关成核/生长改性机制的信息。研究发现，EDTA分子抑制硫酸钡成核，这可能是其抑制硫酸钡沉淀的主要方式。
