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 Cu-0, Co-0, Ag-0 and Ni-0 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, Cu-0 nanoparticlestemplated 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.