Kinetics of CO2 nanobubble formation at the solid/water interface.
The kinetics of adsorption of CO(2) molecules dissolved in aqueous solution onto a hydrophobised silica surface were investigated using a quartz crystal microbalance (QCM). The results of this investigation were compared with those obtained earlier from tapping mode atomic force microscopy (TMAFM) under the same experimental conditions (J. Yang, J. Duan, D. Fornasiero, J. Ralston, J. Phys. Chem. B., 2003, 107(25), 6139-6147; ref. 1). The QCM results represent the early stage of CO(2) gas adsorption (<20 min), before CO(2) gas bubbles adsorbed on the surface can be directly observed by TMAFM. The QCM results confirmed our observation from TMAFM imaging: that CO(2) gas molecules present in solution only adsorb on silica when its surface is hydrophobic. More importantly, the results showed that gas adsorption/bubble growth undergoes two consecutive kinetic processes: a slow and a fast adsorption process.
Ian Wark Research Institute, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095, Australia.
Jingwu
J
Yang
Jinming
J
Duan
Daniel
D
Fornasiero
John
J
Ralston
D000327:Adsorption; D002245:Carbon Dioxide / Q000737:chemistry*; D003460:Crystallization; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D018625:Microscopy, Atomic Force / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry
D012996:Solutions; D014867:Water; D002245:Carbon Dioxide; D006046:Gold; D012822:Silicon Dioxide