Taylor Shawn D, Czarnecki Jan, Masliyah Jacob
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2G6, Canada.
J Colloid Interface Sci. 2002 Aug 1;252(1):149-60. doi: 10.1006/jcis.2002.8403.
In the oil sands industry, undesirable water-in-oil emulsions are often formed during the bitumen recovery process where water is used to liberate bitumen from sand grains. Nearly all of the water is removed except for a small percentage (approximately 1 to 2%), which remains in the solvent-diluted bitumen as micrometer-sized droplets. Knowledge of the colloidal forces that stabilized these water droplets would help to increase our understanding of how these emulsions are stabilized. In this study, the thin liquid film-pressure balance technique has been used to measure isotherms of disjoining pressure in water/toluene-diluted bitumen/water films at five different toluene-bitumen mass ratios. Even though a broad range of mass ratios was studied, only two isotherms are obtained, indicating a possible change in the molecular orientation of surfactant molecules at the bitumen/water interfaces. At low toluene-bitumen mass ratios, the film stability appears to be due to a strong, short-range steric repulsion created by a surfactant bilayer. Similar isotherms were obtained for water/toluene-diluted asphaltene/water films, indicating that the surface active material at the interface probably originated from the asphaltene fraction of the bitumen. However, unlike the bitumen films, films of toluene-diluted asphaltenes often formed very rigid interfaces similar to the "protective skin" described by other researcher.
在油砂行业中，在沥青回收过程中常常会形成不良的油包水乳液，在此过程中用水将沥青从砂粒中分离出来。几乎所有的水都被除去了，只有一小部分（约1%至2%）以微米级液滴的形式残留在溶剂稀释的沥青中。了解稳定这些水滴的胶体作用力将有助于增进我们对这些乳液如何稳定的理解。在本研究中，采用薄液膜压力平衡技术，在五种不同的甲苯 - 沥青质量比下测量水/甲苯稀释沥青/水膜中的分离压力等温线。尽管研究了广泛的质量比范围，但只得到了两条等温线，这表明沥青/水界面处表面活性剂分子的分子取向可能发生了变化。在低甲苯 - 沥青质量比下，膜的稳定性似乎归因于由表面活性剂双层产生的强烈的短程空间排斥力。水/甲苯稀释沥青质/水膜也得到了类似的等温线，这表明界面处的表面活性物质可能源自沥青的沥青质部分。然而，与沥青膜不同的是（此处原文可能有误，根据前文推测应为“与沥青质膜不同的是”），甲苯稀释沥青质的膜通常会形成非常刚性的界面，类似于其他研究人员所描述的“保护皮”。
