Magnetic ordered mesoporous carbon materials for adsorption of minocycline from aqueous solution: Preparation, characterization and adsorption mechanism

In this paper, the effect of cyanoguanidine (CNGE) for tailoring pore size during the soft-templating preparation of mesoporous carbon materials was studied. In consideration of cyclic utilization, the surface of the mesoporous carbon materials were doped with magnetic Fe3O4 particles. The characterization results (including TEM, XRD, BET, TGA and FT-IR) showed that adding CNGE did not destroy the ordered porous structure; instead, it changed the pore size from 2.98 nm to 9.42 nm. Besides, the mesoporous carbon materials exhibited a strong magnetic response owing to the dopant of Fe3O4 particles. With the increase in CNGE, some functional groups were added to the surface of the mesoporous carbon materials, which partly promoted the adsorption effect. The results indicated that adsorption approached equilibrium in the first 10 min and reached the maximum when the pore size was 5.89 nm. The kinetic of minocycline adsorption on magnetic ordered mesoporous carbon material could be interpreted by a pseudo-first-order model. The adsorption isotherms showed that the adsorption process was complex, combining physical and weak chemical adsorption, in good agreement with the Sips model.