Keratinous Materials as Novel Absorbent Systems for Toxic Pollutants

A range of hazardous organic and inorganic compounds, and metal ions generated by human and industrial activities leads to serious concerns for environments: Adsorption technologies based on polymeric materials are being used to remove toxic substances from air and wastewater streams. Keratin protein, found abundantly in sheep's wool, human hair and bird feathers, is an interesting and potentially useful renewable biopolymer. It contains a variety of functional groups on the backbone and side chains of the proteins, and is an ideal component to fabricate a range of novel adsorbent systems for separation of toxic pollutants via physisorption or chemisorption mechanisms. In this review article, the key activities on keratin research and development with respect to the novel properties of keratin proteins and their utilization as absorbents or filtration systems are summarized. It is apparent that keratins in the form of loose fibers, non-woven fabrics, short fibers or particles, membranes and colloids can be used as absorbents for air filtration and wastewater treatment. Keratin materials have potential to be applied in biological and chemical defence applications, and also in protection against radioactive elements.