Freezing of simple fluids in microporous activated carbon fibers: Comparison of simulation and experiment

Ravi Radhakrishnan, Keith E. Gubbins, Ayumi Watanabe, Katsumi Kaneko
1999 Journal of Chemical Physics  
We study the freezing of CCl 4 in microporous activated carbon fibers ͑ACF͒, using Monte Carlo simulation and differential scanning calorimetry ͑DSC͒. Microporous activated carbon fibers are well characterized porous materials, having slit-shaped pores due to the voids formed between graphitic basal planes. They serve as highly attractive adsorbents for simple nonpolar molecules, the adsorbent-adsorbate interaction being mostly dispersive ͑of the van der Waals-type͒. Recent molecular simulation
more » ... studies have predicted an upward shift in the freezing temperature (⌬T f ϭT f ,pore ϪT f ,bulk Ͼ0) for simple fluids confined in such highly attractive carbon slit pores. Our DSC experiments verify these predictions about the increase in T f . The results also indicate significant deviation from the prediction of ⌬T f based on the Gibbs-Thomson equation ͑simple capillary theory͒. We employ a recently developed free energy method to calculate the exact freezing temperature in these confined systems using molecular simulation, in order to address the failure of the simple capillary theory.
doi:10.1063/1.480261 fatcat:dpepibkqdfewtmbbc7u5av5dzy