Revealing the Effect of MnO 2 , Activated Carbon and MnO 2 /Activated Carbon on Chitosan Polymer Host Fabricated Co NPs: Antibacterial Performance and Degradation of Organic Compounds.

MnO 2 and MnO 2 blended with 1 and 2 weight percent of activated carbon (AC), MnO 2 /AC1 and MnO 2 /AC2 were synthesized through the sol-gel method. The pure chitosan (CS) films were cast in the form of films. Similarly, 5 weight% of each MnO 2 , AC, MnO 2 /AC1 and MnO 2 /AC2 was intermingled with the CS to produce different films, such as CS-AC, CS-MnO 2 , CS-MnO 2 /AC1 and CS-MnO 2 /AC2. Zero-valent Co NPs were then supported on these films through the chemical reduction method and expressed as CS@Co, CS-AC@Co, CS-MnO 2 @Co, CS-MnO 2 /AC1@Co and CS-MnO 2 /AC2@Co NPs. All the catalysts were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The synthesized catalysts were used as a dip catalyst against the hydrogenation of 4-nitrophenol (4NP), and for the degradation of methyl orange (MO) and Congo red (CR) dyes. The k app and R 2 values were deduced from pseudo-first-order kinetics for 4NP and MO and zero-order kinetics for CR dye. The k app values of CS-AC@Co and CS-MnO 2 /AC1@Co NPs for 4NP hydrogenation were higher than those for any other member of the series, at 1.14 × 10 -1 and 1.56 × 10 -1 min -1 respectively. Similarly, the rate of CR degradation was highest with CS-AC@Co. The R 2 values for 4NP, MO and CR dyes were above 0.9, which indicated that the application of pseudo-first- and zero-order models were appropriate for this study. Furthermore, the antibacterial activity of all the catalysts was evaluated against Pseudomonas aeruginosa and Escherichia coli . The CS-AC@Co NPs exhibited the highest zone of inhibition compared to other catalysts against P. aeruginosa , while all the catalysts were inactive against E. coli . This study reveals that the catalyst can be used for the degradation of other pollutants and for microbial inhibition.