Adsorption of n-hexane vapor by macroporous and hypercrosslinked polymeric resins: Equilibrium and breakthrough analysis

The adsorption behaviors of n-hexane vapor onto macroporous and hypercrosslinked polymeric resins were investigated. All adsorption isotherms were nonlinear and well fitted with Dubinin–Astakov equation. The equilibrium adsorption data showed that the adsorption capacities of hypercrosslinked polymeric resin (Hyper-resin) were superior to macroporous polymeric resin (Macro-resin) for lower concentration of n-hexane; however, Macro-resin had higher adsorption capacities than Hyper-resin for higher concentration of hexane. The isosteric enthalpies of adsorption for n-hexane were calculated. The Hyper-resin exhibited much higher values of △Hst for n-hexane than Macro-resin at the whole loading studied, indicating that the interaction force of n-hexane adsorption onto Hyper-resin was larger than Macro-resin. The consecutive column adsorption–desorption cycles were carried out to investigate the dynamic adsorption characteristics. The results revealed that the breakthrough adsorption capacities of n-hexane onto the virgin Hyper-resin were about 105% and 43% higher than those onto the virgin Macro-resin when the initial concentrations of n-hexane were 85 mg/g and 510 mg/g, respectively. Due to higher regeneration efficiency, however, the breakthrough capacities of the regenerated Macro-resin were higher than those of the regenerated Hyper-resin for the adsorption of higher concentration n-hexane.

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► Dubinin–Astakov equation described the adsorption isotherms well.
► Hyper-resin showed good adsorption capacities for low concentration of hexane.
► Macro-resin had a potential advantage to adsorb high concentration of hexane.
► Macro-resin can be regenerated more efficiently than Hyper-resin.