Enhancement of methane–water volumetric mass transfer coefficient by inhibiting bubble coalescence with electrolyte

The effect of electrolyte on methane–water volumetric mass transfer coefficient (kLa) was investigated in this study. Various electrolytes including MgSO4, K2SO4, Na2SO4, MgCl2, KCl, NaCl, MgBr2, NaBr, KBr, Mg(NO3)2, KNO3, and NaNO3 were employed and enhancement of kLa from 103 h−1 (in pure water) to 711 h−1 was observed, depending on electrolyte type and concentration. This is the highest methane–water kLa value measured at ambient condition. For all electrolytes, ions with large charge density (charge valency per ionic volume) exhibited larger enhancement in methane–water kLa values. Furthermore, anions exhibited larger influence than cations on the enhancement of kLa. Enhancement of methane–water kLa by electrolytes was due to the inhibition of methane bubble coalescence.

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