Drying of Ionic Liquid

Room Temperature Ionic Liquids (RTILs) are salts in liquid phase. Continuous use of
RTIL in a process may cause it to be contaminated with water and organic impurities
over time. It is necessary to regenerate and purify the RTIL for recycle purposes.
Drying is needed during pre-treatment and purification of IL solution before it can be
used in any application to reduce weight, increase ease of handling and eliminate
unwanted effects of moisture content towards IL properties. Drying process of ionic
liquid is important since moisture levels that are too high may affect performance and
reliability in most applications such as during synthesis of RTILs using aqueous
solution to necessitate anion exchange and also in concentrating Benfield solution for
recycles purposes during removal of CO2. Therefore, to obtain the most optimum
condition of drying for ionic liquids, the study on kinetic of drying is reported here by
investigate the effects of different operating temperature towards drying of ionic liquid,
effect of different anion and cation and drying using different equipment. Ionic liquids
containing [bmim] cation with [SO4]- or Phosphate-containing anion were used and
drying methods applied were halogen lamp and vacuum drying methods.
Thermogravimetric analysis which measures change of mass over time throughout the
drying process was used to generate primary drying curves which were then
manipulated to get secondary kinetic data. The drying process mainly occurred during
falling rate period. Samples dried under higher temperature using vacuum drying have
higher maximum drying rates, lower final moisture contents, higher drying constants
and shorter drying times. The same result is observed for samples containing smaller
anion.