Facile synthesis of porous carbon/Fe₃O₄ composites derived from waste cellulose acetate by one-step carbothermal method as a recyclable adsorbent for dyes

The porous carbon/Fe₃O₄ composites have been used to adsorb the dyes recently, however, most carbon sources are not preferable for the environment protection. In this paper, the porous carbon/Fe₃O₄ composites were synthesized by a simple step carbonization method using the waste cigarette butts and the ferric nitrate as carbon source and oxidizer, respectively. Notably, the obtained products can be reused. The results show that the crystallite size of as-prepared Fe₃O₄ will increase at high treating temperature. In addition, the sample of C-Fe₃O₄-1000 possesses the highest saturation magnetization of 92.2 emu g⁻¹, and the sample of C-Fe₃O₄-600 has the highest specific surface area of 90.23 m² g⁻¹ and the maximum adsorption of 102.04 mg g⁻¹ for methyl orange. Furthermore, the adsorbent can maintain an excellent adsorption capacity for the dye after 4 cycles. Therefore, as-prepared porous carbon/Fe₃O₄ composite is an excellent candidate for recyclable dye adsorbent, and the waste can be converted into products for reducing the environment pollution.