On the Understanding of the Adsorption of 2-Phenylethanol on Polyurethane-Keratin based Membranes

Polymers and specifically hybrid polymeric membranes have been identified as effective formulations in adsorption processes. Nevertheless, the adsorption mechanisms associated with their thermodynamics and kinetics are not fully understood, particularly when these polymeric membranes are used to adsorb 2-Phenylethanol (2-PE) to intensify its production in a specific bioconversion process. This work was aimed at giving phenomenological insights on the adsorption of 2-PE on a set of novel porous hybrid membranes based on polyurethane and keratin biofiber obtained from chicken feathers. Feathers, considered as a waste by-product of the poultry industry, represent an alternative source of keratin, a biopolymer that can be used to design low-cost materials from natural resources. Two types of hybrid membranes were prepared. i.e. composite and copolymer. Firstly, these materials were characterized by scanning electron microscopy (SEM), infrared spectroscopy (FT-IR) (before and after the adsorption process) and X-Ray (WAXD) analysis. Secondly, these materials, including the reference ones (keratin biofiber and polyurethane), were evaluated during the removal of 2-PE, relating their adsorption capabilities to physiochemical properties elucidated during the characterization. Particularly a composite with 0.1 g of chicken-feather-keratin (C1) presented the highest removal percentage (60.68%), a significant initial adsorption rate (0.2340 mg(PE).h(-1).g(A)(-1)), the maximum adsorption capacity (12.13 mg(PE).g(A)(-1)) and the best stability and mechanical properties at studied operating conditions. In comparison with results reported in literature, in this composite carbonyl functional groups from polyurethane showed rather major affinity to 2-PE than amino groups from the keratin biofiber. To this end, parameters associated with its industrial application were obtained, namely thermodynamic and kinetic information was obtained from a proper design of experiments and phenomenological models based on adsorption macroscopic fundamentals.