文献类型：期刊文献

英文题名：Effect of salt concentration on the phase separation of bitumen emulsions

作者：Yang, Qianqian[1];Ke, Dan[1];Yang, Mingling[1];Hong, Jinxiang[2];Ran, Qianping[2];Wang, Xiaoyong[1]

机构：[1]E China Univ Sci & Technol, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China;[2]Jiangsu Acad Bldg Sci Co Ltd, State Key Lab High Performance Civil Engn Mat, Nanjing 210008, Jiangsu, Peoples R China

年份：2013

卷号：425

起止页码：1

外文期刊名：COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS

收录：;EI(收录号：20131316154274);WOS:【SCI-EXPANDED(收录号:WOS:000318133300001)】；

基金：This work is supported by the National Natural Science Foundation of China (Grant 21173081), the Natural Science Foundation of Shanghai (Grant 11ZR1408600), the National Basic Research Program of China (973 Program, Grant 2012CB724601), the Fundamental Research Funds for the Central Universities (Grant WK1213003), and State Key Laboratory of High Performance Civil Engineering Materials (Grant 2010CEM007).

语种：英文

外文关键词：Bitumen emulsion; Phase boundary; Salt concentration; Zeta potential; Density

摘要：This work has studied pronouncedly different phase separation situations for bitumen emulsions at various salt concentrations. With increasing sodium chloride concentration (C-NaCl), the added salt promotes the degree of phase separation of bitumen emulsions at C-NaCl lower than 5.2 mM, where the separated water is the upper phase and the bitumen is the lower phase. Nevertheless, this kind of phase separation is gradually reduced as C-NaCl increases from 5.2 to 250 mM. At C-NaCl = 250-500 mM, the bitumen emulsions with very low degree of phase separation are observed to transit from the aqueous phase in the upper position and the bitumen phase in the lower level into the reverse situation. Further increase of salt amount in bitumen emulsions leads to the enhanced phase separation at C-NaCl = 500-830 mM. These results of phase separation of bitumen emulsions are explained as the combined influences of the screening effect on the electrostatic repulsion of the bitumen droplets and the density changes of the aqueous phase induced by the added salt. While the salt screening effect is responsible for the increased phase separation at C-NaCl smaller than 5.2 mM, other phase separation behaviors at higher salt amounts may be mainly attributed to the increasing density values of the aqueous phase due to the salt addition. (c) 2013 Elsevier B.V. All rights reserved.