Aeration and dissolution behavior of oxygen nanobubbles in water

Document Type

Article

Publication Date

3-1-2022

Abstract

Hypothesis: Nanobubbles (NBs) in water elicit unique physicochemical and colloidal properties (e.g., high stability and longevity). Aeration kinetics and dissolution behavior of oxygen (O2) NBs are assumed to be bubble size dependent. Experiments: As an indicator for aeration efficiency, volumetric mass transfer coefficient (KL·a) was assessed by measuring the dissolved oxygen (DO) levels during aeration using O2 NBs with different sizes. Mass transfer coefficient (KL) was estimated by correlation analysis. Moreover, a modified Epstein-Plesset (EP) model was developed to predict the dissolution behavior by monitoring the DO and size changes during the dissolution of O2 NBs in water. Findings: A higher rate of DO increase and a higher equilibrium DO level were both observed after aeration with NBs that present higher surface areas for the mass transfer of O2 and a higher vapor pressure of O2 to drive the partitioning equilibrium. Dissolution kinetics of O2 NBs were highly dependent on the initial bubble size as indicated by the changes of bubble size and DO. Smaller NBs raised up DO faster, whereas larger NBs could lead to higher equilibrium DO levels. Moreover, the rate of DO decline and the quasi-steady DO levels both decreased when the dilution ratio increased, confirming that O2 NBs dictates the DO level in water. Finally, the dissolving NBs may either swell or shrink according to the model prediction.

Identifier

85119446371 (Scopus)

Publication Title

Journal of Colloid and Interface Science

External Full Text Location

https://doi.org/10.1016/j.jcis.2021.11.061

e-ISSN

10957103

ISSN

00219797

PubMed ID

34815086

First Page

584

Last Page

591

Volume

609

Grant

2018-07549

Fund Ref

National Science Foundation

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