Facile synthesis of magnetic resorcinol-formaldehyde (RF) coated carbon nanotubes for methylene blue removal

In this paper, magnetic resorcinol-formaldehyde (RF) resin coated carbon nanotubes were synthesized from hydrophilic magnetic carbon nanotubes (CNTs) with the extended Stober method. Firstly, magnetic CNT composites (CNTs@Fe3O4) were synthesized by the high temperature decomposition process using the iron acetylacetonate as raw materials. Then the resorcinol-formaldehyde polymer can be easily coated on the magnetic CNTs with the extended Stober method. Finally, numerous of gold nanoparticles were assembled on the surface of CNTs@Fe3O4@RF by reducing Au3+ between the RF shell and HAuCl4 solution; meanwhile, the mesoporous carbon coated CNTs@Fe3O4 can also be obtained by calcinations of the CNTs@Fe3O4@ RF composites in nitrogen atmosphere. The resulting CNTs@Fe3O4@RF@Au or CNTs@Fe3O4@C composites show not only a magnetic response to an externally applied magnetic field, but also can be a kind of catalyst or adsorbent to catalyze or adsorb the methylene blue (MB), in the ambient temperature.