Chitosan-titanium oxide fibers supported zero-valent nanoparticles: Highly efficient and easily retrievable catalyst for the removal of organic pollutants.

Different chitosan-titanium oxide (CS-TiO2 -x, with x = TiO2 loadings of 1, 5, 10,15 and 20 wt%) nanocomposite fibers were prepared and kept separately in each salt solution of CuSO4 , CoNO3 , AgNO3 and NiSO4 to adsorb Cu2+ , Co2+ , Ag+ , and Ni+ ions, respectively. The metal ions loaded onto CS-TiO2 fibers were reduced to their respective zero-valent metal nanoparticles (ZV-MNPs) like Cu0 , Co0 , Ag0 and Ni0 by treating with NaBH4 . The CS-TiO2 fibers templated with various ZV-MNPs were characterized and investigated for their catalytic efficiency. Among all prepared ZV-MNPs, Cu0 nanoparticles templated on CS-TiO2 -15 fibers exhibited high catalytic efficiency for the reduction of dyes (methyl orange (MO), congo red (CR), methylene blue (MB) and acridine orange (AO)) and nitrophenols (4-nitrohphenol (4-NP), 2-nitrophenol (2-NP), 3-nitrophenol (3-NP) and 2,6-dinitrophenol (2,6-DNP)). Besides the good catalytic activities of Cu/CS-TiO2 -15 fibers, it could be easily recovered by simply pulling the fiber from the reaction medium.