Comprehensive Analysis of the Quality of Colloidal Gas Aphrons: Impact of Batch and Batch-Recirculation Modes of Operation on Air Holdup and Stability

• Published in: Topics in catalysis Vol. 68; no. 11; pp. 1094 - 1109
• Main Authors: Arora, Isha, Yousuf, Taybah, Malik, Faryal, Manzoor, Sameena, Bhaskarwar, Ashok N.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2025; Springer Nature B.V
• Subjects: Aeration; Aphrons; Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Enhanced oil recovery; Industrial Chemistry/Chemical Engineering; Original Paper; Pharmacy; Physical Chemistry; Porous materials; Soil remediation; Stability; Surfactants; Anionic surfactant; Stability; Batch; Batch-recirculation; Colloidal gas aphrons (CGAs); Air holdup; Sodium lauryl sulphate (SLS)
• ISSN: 1022-5528; 1572-9028
• DOI: 10.1007/s11244-025-02108-w

Colloidal Gas Aphrons (CGAs) are microbubbles with a stable air core, surrounded by a hydrogen-bonded aqueous shell and surfactant bilayers. They are generated in a specially designed baffled generator using surfactant solutions at high rotational speeds exceeding a critical threshold. While CGAs have diverse applications, including enhanced oil recovery, aerated concrete production, soil and water remediation, and porous material synthesis, limited understanding exists regarding their properties variations when generated in a recycle mode of operation. The present paper systematically explores experimentally both the batch and batch-recirculation modes to evaluate their influence on the CGAs quality, specifically focusing on air holdup and stability. A meticulous examination of the effects of surfactant concentration, disc rotational speed, and CGAs recirculation rate offers valuable insights into the dynamics of formation and overall stability of CGAs. Furthermore, the anticipated distinctions between the outcomes of batch and batch-recirculation modes of operation of a CGAs generator are analyzed and discussed. Batch-recirculation demonstrates negligible influence on the air holdup and volume of CGAs generated over extended durations, yielding results comparable to those observed in batch mode. Nonetheless, a noticeable enhancement in the CGAs build-up occurs during the initial stages of the recirculation mode of operation. While long-term batch-recirculation shows minimal impact on the overall generation of CGAs, reflected in similar air holdup values and volumes as in standard batch mode, it demonstrates a rapid initial formation. After 5 min of CGAs generation in batch and batch-recirculation modes at 4000 RPM, the air holdup was 0.3 and 0.45, respectively, and height of CGAs dispersion was 9.9 cm and 11.2 cm, respectively. This early-stage enhancement during recirculation suggests improved generation kinetics, although the final CGAs yield remains comparable between both modes. This experimental finding may have an important bearing on large-scale batch generation of CGAs and optimization of such production processes in practice.