Luo Ximei, Lin Qiqiang, Wen Shuming, Wang Yunfan, Lai Hao, Qi Linping, Wu Xuetong, Zhou Yongfeng, Song Zhenguo
Faculty of Land and Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China.
State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China.
Langmuir. 2021 Jan 26;37(3):1235-1246. doi: 10.1021/acs.langmuir.0c03248. Epub 2021 Jan 12.
In this study, the effect of sodium dodecyl sulfonate (SDS) on the foam stability of dodecylamine (DDA) and on its adsorption configuration at the gas-liquid interface was investigated. Froth stability experiments, surface tension measurements, time-of-flight secondary-ion mass spectrometry measurements, and molecular dynamics simulation calculations were performed in this investigation. The results revealed that the foam stability of DDA solution was extremely strong, and the addition of SDS could decrease the foam stability when the concentration of DDA was less than a certain value. The decrease in foam stability could be ascribed to several reasons, namely, the big cross-sectional area of SDS at the gas-liquid interface and low adsorption capacity of surfactants at the gas-liquid interface, the high surface tension, the change in the double-layer structure, the small thickness of the gas-liquid interfacial layer, the weak interaction intensity between the head groups of the surfactants and the water molecules, the strong movement ability of the water molecules around the head groups, and the sparse and less upright arrangement configuration of molecules at the gas-liquid interface. These findings can greatly help in solving the strong foam stability problem in DDA flotation and provide a method for reducing foam stability.
在本研究中，研究了十二烷基磺酸钠（SDS）对十二烷基胺（DDA）泡沫稳定性及其在气液界面吸附构型的影响。本研究进行了泡沫稳定性实验、表面张力测量、飞行时间二次离子质谱测量和分子动力学模拟计算。结果表明，DDA溶液的泡沫稳定性极强，当DDA浓度小于某一值时，添加SDS可降低泡沫稳定性。泡沫稳定性的降低可归因于几个原因，即SDS在气液界面的横截面积大、表面活性剂在气液界面的吸附能力低、表面张力高、双层结构的变化、气液界面层厚度小、表面活性剂头基与水分子之间的相互作用强度弱、头基周围水分子的运动能力强以及气液界面处分子排列稀疏且直立程度低。这些发现对解决DDA浮选过程中泡沫稳定性强的问题有很大帮助，并提供了一种降低泡沫稳定性的方法。
