Adsorption and Release Behavior of Vitamin B12 in Tubular Structured Ordered Mesoporous Carbon

Ordered mesoporous carbon with hexagonal arrays consisting of tubular-type pores (CMK-5) was synthesized via a nanocasting process by the direct use of SBA-15 as a template, furfuryl alcohol as a carbon source and oxalic acid as the catalyst. The structure of CMK-5 was analyzed by different techniques including scanning electron microscopy, powder X-ray diffraction and N₂ adsorption analysis. The specific surface area and pore volume were found to be 1856 m²·g^-1 and 2.10 cm³·g^-1, respectively, with mesopore sizes concentrated at 3.1 and 5.5 nm. Because of the unique structure the adsorption capacities of CMK-5 towards vitamin B12 was found to be as high as 943 mg·g^-1 in a short period of 120 min, which is significantly higher than that of commercial activated carbon. The composites of CMK-5 and vitamin B12 without any treatment gave slow-release performance in a simulated body fluid. The concentration of the release solutions remained 9 mg·L^-1 under dynamic conditions. A high loading capacity and slow release rate of vitamin B12 on the CMK-5 support suggested that CMK-5 might have a potential application in drug delivery.