Colloidal gas aphrons (CGA): Dispersion and structural features

Colloidal gas aphrons (CGA) have previously been defined as surfactant stab ilized gas microbubbles and characterized for a number of surfactants in te rms of stability, gas holdup and bubble size even though there is no conclu sive evidence of their structure (that is, orientation of surfactant molecu les at the gas-liquid interface, thickness of gas-liquid interface, and/or number of surfactant layers). Knowledge of the structure would enable us to use these dispersions more efficiently for their diverse applications (suc h as for removal of dyes, recovery of proteins, and enhancement of mass tra nsfer in bioreactors). This study investigates dispersion and structural fe atures of CGA utilizing a range of novel predictive (for prediction of aphr on size and drainage rate) and experimental (electron microscopy and X-ray diffraction) methods. Results indicate structural differences between foams and CGA, which may have been caused by a multilayer structure of the latte r as suggested by the electron and X-ray diffraction analysis.