Adsorption is also the process employed for the removal of phenylalanine from protein hydrolysates in the preparation of Phe-free dietary formulas for treatment of phenylketonuria patients (Clark, Alves, Franca, & Oliveira, 2012). Many studies have been reported in the scientific literature dealing with the adsorption of phenylalanine on materials such as activated carbons, zeolites, Venetoclax cell line ion exchangers, polymeric resins and others (Díez et al., 1998, Titus et al., 2003, Garnier et al., 2007, Piao et al., 2009, Ghosh et al., 2011 and Fei-Peng et al., 2012). However, high costs are associated with the production and regeneration of such adsorbents

and these costs could be reduced by the use of low-cost adsorbents (Clark et al., 2012). Agricultural wastes are the most common raw materials being studied as potential precursors for the preparation of low-cost adsorbents, since they are renewable, available in large amounts and potentially less expensive than other

materials to manufacture a diversity of adsorbents. Brazil is the third largest corn producer in the world, with an expected production of almost 52 million tons in 2012. Solid residues from corn production such as corn cobs present great potential for use as raw materials in the production of adsorbents (Bagheri & Abedi, 2011). Reports on the use of agricultural residues for Phe removal from aqueous solutions by adsorbents based on agricultural click here Forskolin residues are not available in the literature, with the exception of our previous study employing defective coffee bean press cake (Clark et al., 2012). Changes in the precursor material significantly modify the physico-chemical characteristics of the adsorbing surfaces and thus significantly affect the types of adsorbate–adsorbent interactions, which, in the case of phenylalanine, range from hydrogen bonding to Coulombic to hydrophobic interactions.

Hence, studies of adsorption of phenylalanine onto residue-based adsorbents will contribute to a better understanding of the adsorption of this type of amino acid on such materials and also provide theoretical guides for the implementation of practical processes such as separation or purification of this amino acid. In view of the aforementioned, the objective of this work was to evaluate the performance of corn cobs in the production of adsorbents for Phe removal from aqueous solutions. Corn cobs were provided by EMBRAPA (Sete Lagoas, Brazil). The phenylalanine standard and other reagents were purchased from Sigma–Aldrich (SP, Brazil). The adsorbent was prepared according to the procedure employed in a previous study (Clark et al., 2012) using coffee press cake as a precursor material (3 min impregnation with H3PO4 followed by 1 h activation in a muffle furnace). The activated material was cooled under nitrogen and washed with distilled water until constant pH = 6, dried at 105 °C for 24 h and ground (Arbel grinder, São Paulo, Brazil, 0.15 < D < 1.00 mm).