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

Abstract

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.