Acute effect of trace component on capillary phase transition of n-alkanes

Abstract

The significant influence of trace chain molecules on the capillary phase transition (CPT)of n-alkanes in porous carbon is investigated systematically for the first time using aclassical density functional theory (DFT). It is discovered that: (i) the CPT ofn-alkanes can be adjusted to occur at a much lower concentration than whenthe trace chain component is absent; (ii) potential parameters of the trace chainmolecule, and its concentration in the bulk, show their acute effects within aparticular range beyond which the modulation effect eventually becomes a bitconstant; (iii) an acute modulation effect can be induced only if the number ofsegments per trace chain molecule is larger than or equal to that of the segments peralkane considered. The present discoveries have implications for the separation andenrichment of low concentration components, and easy and precise control ofCPT.