BUBBLE-COLUMN APPARATUS FOR GAS-LIQUID HETEROGENEOUS CHEMISTRY STUDIES

A bubble column apparatus has been designed to conduct time-resolved g as-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 co ntrolled by means of a stepping motor. Modeling of the gas uptake and the validation of the apparatus performance are described. The apparat us 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 s pecies (reaction rate k) the apparatus measures Hk(1/2) values in the range 0.08-100 (M/atm) s(-1/2).