Surface modification of activated carbon fiber and its adsorption for vitamin B1 and folic acid

The activated carbon fiber was treated by nitrocellulous combustion and nitric acid oxidization to introduce amide and hydroxyl groups on its surface. The pore structure, surface morphology and chemical groups were investigated by nitrogen adsorption isotherms, SEM and FTIR. The result showed that the pore structure and surface morphology were not much affected, but the amide and hydroxyl groups could be introduced after modification. The adsorption properties of folic acid and vitamin B1 indicated that the pore structure determined the saturated adsorption capacity at low concentration; however, the ACF-NC and ACF-HNO3 showed the highest adsorption capacity and fastest adsorption rate for folic acid and vitamin B1 due to the amide and hydroxyl group on their surfaces at high concentration.