Pyrolysis of polyaniline-poly(styrene sulfonate) hydrogels to prepare activated carbons for the adsorption of vitamin B12

In this study, polyaniline-poly(styrene sulfonate) (PAn-PSS) hydrogels were pyrolyzed to obtain activated carbons for the adsorption of vitamin B12 molecules for the first time. The structural properties of the as-prepared activated carbons were characterized with scanning electron microscope (SEM), nitrogen absorption-desorption, and Fourier transform infrared spectroscopy (FTIR). The resulting activated carbon samples maintained the previous network structure of the hydrogels. The optimum carbonization temperature was determined. The activated carbons which were prepared under the optimum condition possessed high mesoporous ratio of above 70%. In addition, these activated carbon samples were nitrogen-enriched due to the PAn-PSS precursor. The adsorption tests indicated that these activated carbons had preferable adsorption ability for vitamin B12 and were favorable to be used in the separation and purification of vitamin B12. Adsorption data of vitamin B12 on PAn-PSS based activated carbons were well modeled by Langmuir equation. The adsorption kinetic data were following the pseudo second order model. (C) 2014 Published by Elsevier B.V.