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International Journal of Polymer Science
Volume 2013, Article ID 892547, 12 pages
Research Article

Polyurethane-Keratin Membranes: Structural Changes by Isocyanate and pH, and the Repercussion on Cr(VI) Removal

1Posgrado en Ciencia de Materiales, Facultad de Química, Universidad Autónoma del Estado de México, Paseo Colón Esquina, Paseo Tollocan, 50120 Toluca, MEX, Mexico
2Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Facultad de Química, Universidad Autónoma del Estado de México, Km. 14.5 de la carretera Toluca-Atlacomulco, 50200 San Cayetano, MEX, Mexico
3División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Querétaro, Avenida Tecnológico s/n, Esquina Gral. Mariano Escobedo, 76000 Colonia Centro Histórico, QRO, Mexico
4Centro de Física Aplicada y Tecnología Avanzada, UNAM, AP 1-10101, 76000 Juriquilla, QRO, Mexico
5División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Cd. Madero, J. Rosas y J. Urueta s/n, Colonia Los Mangos, 89440 Ciudad Madero, TAMPS, Mexico

Received 1 May 2013; Revised 1 August 2013; Accepted 20 August 2013

Academic Editor: Qian Yang

Copyright © 2013 María D. Manrique-Juárez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Keratin has the capacity to interact with metal ions. In order to take advantage of this potential, a novel membrane with polyurethane and keratin has been developed and studied for removal of Cr(VI) from aqueous solution. Physicochemical and morphological properties of these hybrid membranes were studied, varying synthesis parameters such as the type of isocyanate and pH in keratin solution. The effects of using diphenyl-methane-diisocyanate or toluene-diisocyanate and modifying the pH in keratin solutions were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy, and dynamical mechanical analysis. Results show that pH has a strong influence on morphology and on Cr(VI) removal efficiency. When pH in keratin solution is low (2.5), the protein separates from water, and a more closed cell in the membrane is obtained affecting its mechanical properties. The removal efficiency of Cr(VI) was also assessed at different pH values of chromium solutions. These results show that when pH of the Cr solution is acidic (at 1.5), the Cr(VI) removal percentages increase significantly, reaching up to a 58%. Thus this paper demonstrates the successful combination of synthetic and natural polymers depending on the process parameters to be applied in the critical purpose of remediation of Cr(VI) contamination.