BUBBLE-COLUMN APPARATUS FOR GAS-LIQUID HETEROGENEOUS CHEMISTRY STUDIES

A bubble column apparatus has been designed to conduct time-resolved gas-liquid interaction studies of interest in atmospheric chemistry. In the apparatus, a low pressure gas flow, carrying trace gas diluted in helium carrier gas, is 'bubbled' through a flask containing 3.5 L of temperature-controlled liquid. The outlet gas flow is then sampled by a differentially pumped mass spectrometer. The position of the bubble injector, which determines the gas-liquid contact time, is computer controlled by means of a stepping motor. Modeling of the gas uptake and the validation of the apparatus performance are described. The apparatus in the present configuration can measure Henry's law coefficients (H) for nonreactive species in the range 0.01-2.0 M/atm. For reactive species (reaction rate k) the apparatus measures Hk(1/2) values in the range 0.08-100 (M/atm) s(-1/2).