Biosorptive dehydration of tert-butyl alcohol using a starch-based adsorbent: characterization and thermodynamics.

Biosorptive dehydration of tert-butyl alcohol (TBA) using a specially formulated compound starch-based adsorbent was investigated. The net retention time and separation factor of TBA and water were obtained using inverse gas chromatography (IGC), which demonstrated the feasibility of this biosorptive separation process, with low temperature propitious to the process. Through orthogonal experimental design, the optimum adsorption condition was determined from different bed depths, bed temperatures and kettle temperatures. Thermal regeneration experiments showed no change in biosorption capacity after five biosorption/regeneration cycles. Field emission scanning electron microscopy (FESEM) and mercury porosimetry were used to investigate the change in surface morphology and microstructure of the biosorbent before and after adsorption. Finally, the thermodynamic parameters ΔH(s) and ΔG(s) were determined, which indicated that the process occurred by physisorption and was spontaneous and exothermic. The results indicated that the biosorbent can be used as an effective low-cost sorbent to dehydrate TBA.