Magnetic Activated Carbon Derived from Biomass Waste by Concurrent Synthesis: Efficient Adsorbent for Toxic Dyes

The development of advanced carbon nanomaterials that can efficiently extract pollutants from solutions is of great interest for environmental remediation and human safety. Herein we report the synthesis of magnetic activated carbons via simultaneous activation and magnetization processes using carbonized biomass waste from coconut shells (Cb’s) and FeCl₃·6H₂O as precursor. We also show the ability of the materials to efficiently extract toxic organic dyes from solutions and their ease of separation and recovery from the solutions using a simple bar magnet. Textural characterization shows that the materials are microporous. Further analyses of the deconvoluted XPS spectra and X-ray diffraction patterns reveal that the materials possess magnetite, maghemite and hematite. SEM and TEM images show that an increase in the ratio of FeCl₃·6H₂O:Cb leads to an increase in the material’s magnetic properties. The point of zero charge (pH_pzc) indicates that the materials have acidic characteristics. Adsorption kinetic studies carried out onto MAC1 indicates that the Elovich model can satisfactorily describe the experimental data at low initial concentrations and the pseudo-second order model can best fit the data at higher initial concentrations. Moreover, adsorption equilibrium studies reveal that the Langmuir model adequately allows the determination of the materials’ adsorption capacity. Our adsorption and equilibrium fit of the data include nonlinear models and are thus more informative compared with those in other recent, related works, in which only linear fits have been presented. Extensive mechanistic studies for the adsorption processes are also included in the work