Biosorption and selective separation of acetophenone and 1-phenylethanol with polysaccharide-based polymers

A polysaccharide-based polymer (abbrev., SMP) was prepared via the crosslinking of starch with 4,4-methylene diphenyl diisocyanate and employed as an adsorbent for selective separation of acetophenone (AP) and 1-phenylethanol (PE) which coexist extensively in petrochemical by-products and effluents. The successful crosslinking was proved by FTIR and XPS, and the rough morphology as well as porous structure was also demonstrated in XRD, SEM and N2 adsorption-desorption analysis. Using SMP as adsorbent, the adsorption kinetics and isotherms were both investigated in single-component system. Both kinetic and thermodynamic parameters of the adsorption process were obtained. Further thermodynamic investigation indicated that the adsorption was exothermic and spontaneous. Compared to the starch-based polymers whose frameworks contain no phenyl ring, SMP exhibits both higher selectivity and capacity for AP in the competitive adsorption. Additionally, increasing the level of crosslinking in SMP favors its adsorption performance. Furthermore, continuous adsorption-desorption indicated high separation ability and regeneration efficiency of SMP. Finally, the mechanism studies suggested that the adsorption mechanisms may be physisorption involving noncovalent interactions, permitting preference to AP over PE.