Styrene absorption in water/silicone oil mixtures

The absorption of styrene in water/silicone oil systems at a constant flow rate for emulsion compositions ranging from 0% to 20% was investigated using a dynamic absorption method. It was found that the mass transfer for air/water/silicone oil systems is roughly double than those determined for air/water systems whatever the silicone oil percentage (ϕ). This result, mainly due to the high value of the partition coefficient ratio (mR = Hwater/Hoil = 257), was in agreement with the enhancement factor models proposed in the literature. Considering the volumetric mass transfer coefficient, it was shown that change in KLa versus ϕ depended on the mass transfer model used for its determination. By using the “equivalent absorption capacity” concept developed by Dumont et al. [18] (CEJ 162 (2010) 927–934; doi:10.1016/j.cej.2010.06.045), a dramatic decrease in the KLa with increasing silicone oil volume fraction was observed in relation to the decrease in the value of the partition coefficient Hmix. Conversely, considering a styrene mass transfer pathway in series (gas → water → oil), the KLa values for gas/water/silicone oil systems were roughly double the KLa for gas/water systems and did not depend on the mixture composition. The styrene mass transfer performances were also analyzed using the modeling framework proposed by Hernandez et al. [17] (CEJ 172 (2011) 961–969; doi:10.1016/j.cej.2011.07.008). This model confirmed the ability of a water/silicone oil mixture to increase the styrene mass transfer by a factor of 2 and verified that the change in Hmix versus ϕ followed the trend predicted by the theory (although the Hmix values determined from this model were significantly lower than the theoretical values).

► The absorption of styrene in water/silicone oil systems was investigated.
► The mass transfer for air/oil systems is double those determined for air/water system.
► This result is valid whatever the silicone oil percentage (2, 10 or 20% v/v).
► This result is due to the high value of the partition coefficient ratio (mR = 257).