Understanding the merging dynamics of surface nanobubbles and the resulting capillary force between particles from molecular simulations

通过分子模拟了解表面纳米气泡的合并动力学以及颗粒之间产生的毛细管力

• 批准号: 1911434
• 负责人: Zhi Liang
• 金额: $ 27.62万
• 依托单位: California State University-Fresno Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1911434&HistoricalAwards=false
• 关键词: Understanding; merging; dynamics; surface; nanobubbles

Nanobubbles are gas-filled cavities in liquids with diameters ranging from tens to hundreds of nanometers. The key difference between nanobubbles and ordinary, larger bubbles is that larger bubbles rise rapidly to the surface of a liquid and burst, while nanobubbles can remain suspended in liquids for hours or even days. Due to their unique properties, nanobubbles are extremely useful in a broad range of technological applications such as froth flotation, wastewater treatment, detergent-free cleaning, and de-inking. The key process in these applications is the coalescence of nanobubbles on the surfaces of particles, which results in the formation of particle aggregates in a liquid. The main objective of this project is to use numerical simulations and theoretical models to understand the merging dynamics of nanobubbles and the resulting capillary force between adjoining particles. The education activities related to this project will attract high school students, especially those in underrepresented groups, in the central valley (California) to the engineering program, train students to conduct research in bubble dynamics, and guide students toward doctoral research programs in STEM.This project will use molecular dynamics simulations coupled with continuum-based theoretical analysis to study the effects of bubble size, surface tension, contact angle, and surface topology on merging dynamics of nanobubbles and the resulting capillary force between particles coated with nanobubbles. The molecular level modeling will enable the study of microscopic details that are inaccessible to experiments and will provide a fundamental understanding and quantitative predictions of many key aspects of nanobubble dynamics and the nanobubble capillary force between particles. Moreover, such microscopic predictions are not hindered by many assumptions and approximations used in continuum and theoretical modeling. The modeling results will enable practitioners to develop strategies for enhancing the flotation rate of fine/ultrafine mineral particles and to improve removal rates of contaminants in processes such as wastewater treatment, surface cleaning, and recycling of paper.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

纳米气泡是直径从几十纳米到数百纳米的液体中充满气体的空腔。纳米气泡与普通的较大气泡的关键区别在于，较大的气泡迅速上升到液体表面并破裂，而纳米气泡可以在液体中悬浮数小时甚至数天。由于其独特的性质，纳米气泡在泡沫浮选、废水处理、免洗涤剂清洗和脱墨等广泛的技术应用中非常有用。在这些应用中的关键过程是纳米气泡在颗粒表面的结合，这导致在液体中形成颗粒聚集体。该项目的主要目标是使用数值模拟和理论模型来了解纳米气泡的合并动力学以及由此产生的相邻颗粒之间的毛细管力。与该项目相关的教育活动将吸引中央山谷(加利福尼亚州)的高中生，特别是那些未被充分代表的群体参加工程项目，培训学生进行气泡动力学研究，并引导学生进入STEM博士研究项目。该项目将使用分子动力学模拟与基于连续介质的理论分析相结合的方法，研究气泡大小、表面张力、接触角和表面拓扑对纳米气泡合并动力学的影响，以及由此产生的包裹纳米气泡的颗粒之间的毛细管力。分子水平的模拟将能够研究实验无法获得的微观细节，并将提供对纳米气泡动力学和纳米气泡颗粒之间的毛细管力的许多关键方面的基本理解和定量预测。此外，这种微观预测不会受到连续体和理论建模中使用的许多假设和近似的阻碍。建模结果将使从业者能够制定策略，以提高细/超细矿物颗粒的浮选率，并提高废水处理、表面清洁和纸张回收等过程中的污染物去除率。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Nanobubble capillary force between parallel plates

• DOI: 10.1063/5.0075962
• 发表时间: 2022-01
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: E. Bird;Zhixi Liang

Coalescence characteristics of bulk nanobubbles in water: A molecular dynamics study coupled with theoretical analysis

• DOI: 10.1103/physrevfluids.6.093604
• 发表时间: 2021-09
• 期刊: Physical Review Fluids
• 影响因子: 2.7
• 作者: E. Bird;Eric Smith;Zhi Liang

Coalescence speed of two equal-sized nanobubbles

• DOI: 10.1063/5.0030406
• 发表时间: 2020-12
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: E. Bird;Jun Zhou;Zhi Liang