Application of the Diffused Double Layer Theory to Nanobubbles
Application of the Diffused Double Layer Theory to Nanobubbles
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DOI：
10.1021/acs.langmuir.9b01443
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发表时间：
2019-09-17
期刊：
影响因子：
3.9
通讯作者：
Batagoda, Janitha H.
中科院分区：
文献类型：
--
作者：
Meegoda, Jay N.;Hewage, Shaini Aluthgun;Batagoda, Janitha H.
纳米气泡具有带电界面，因此，扩散双层理论可以用来解释纳米气泡在不同电解液中的行为。在本研究中，在不同浓度的NaCI溶液中产生了氧气纳米气泡，并在产生后和1周后测量了气泡的大小和Zeta电位。利用测量数据和扩散双电层理论计算了表面电荷密度、表面电荷产生的电势和气泡间的相互作用能。随着氯化钠浓度的增加，气泡尺寸、表面电荷密度和负电荷数增加，而zeta电位/表面电位、双层厚度、内压和静电斥力的大小减小。1周后观察到相同的趋势。对0.001 M氯化钠溶液的净总能量计算表明，在中等分离距离时，气泡排斥具有6.99×10(-20)J的势垒，从而阻止了气泡的合并。因此，0.001 M氯化钠溶液产生了稳定的纳米气泡。对纳米气泡内部压力的计算表明，随着氯化钠浓度的增加，界面压差减小。实验结果以及扩散双电层和净总能量的计算结果表明，当氯化钠浓度为0.001.1M时，气泡最稳定，而当氯化钠浓度最高时(0.1M)，气泡稳定性最差。
Nanobubbles have electrically charged interfaces; hence, the diffused double layer theory can be applied to explain the behavior of nanobubbles in different electrolytic solutions. In this research, oxygen nanobubbles were generated in NaCI solutions of different concentrations, and bubble size and zeta potentials were measured just after the generation and after 1 week. The measured data and diffused double layer theory were used to compute the surface charge density, the potential due to the surface charge, and the interaction energy between bubbles. With the increased NaCl concentration, bubble size, surface charge density, and the number of negative charges increased, while the magnitude of zeta potential/surface potential, double layer thickness, internal pressure, and the electrostatic repulsion force decreased. The same trend was observed after 1 week. The net total energy calculation for the 0.001 M NaCl solution showed that the bubble repulsion for an intermediate separation distance had a 6.99 X 10(-20) J energy barrier, which prevented bubble coalescence. Hence, the 0.001 M NaCl solution produced stable nanobubbles. The calculation of internal pressure inside nanobubbles showed a reduction in the interfacial pressure difference with the increased NaCl concentration. The test results, as well as diffuse double layer and net total energy calculations, showed that the most stable bubbles were obtained with 0.001 M NaCl concentration and the least stability was recorded with the highest amount (0.1 M) of NaCl concentration.