Preparation and characterisation of magnetically activated carbon derived from palmyra palm kernel shells

Abstract

The contamination of water bodies with toxic pollutants such as heavy metals, dyes, and other harmful substances has increased significantly due to their release into aquatic ecosystems from industrial, urban, and agricultural activities. Among the several treatment techniques for the removal of water pollutants, activated carbon adsorption has received more attention due to its low cost, eco-friendliness, and high adsorption capacity. However, its separation after treatment is more difficult for regeneration. Preparation of magnetically activated carbon is one of the best options since it offers easy separation via an external magnetic field while maintaining a high adsorption capacity. This study mainly focuses on the preparation and characterisation of magnetically activated carbon (MAC) from Palmyra shells. The MAC was prepared using a chemical co-precipitation method and characterised using techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analysis to determine its magnetic properties, morphology, porosity, and surface area. Additionally, iodine number and the Point of Zero Charge (PZC) were determined. The optimum Fe3O4: AC ratio was selected as 1: 3 for developing magnetically activated carbon due to its balanced performance in both Rhodamine B removal and magnetic properties. In XRD analysis, the synthesised MAC contained three characteristic peaks corresponding to the (220), (311), and (440) crystal planes of magnetic ferric oxide. The (311) crystal plane has a higher intensity, suggesting that Fe3O4 has been successfully loaded onto the activated carbon surface. SEM images showed that even after magnetisation, the porosity remained intact on the activated carbon. MAC has a lower iodine number than AC but with sufficient magnetic responsiveness. The appearance of new peaks in the FTIR spectrum after magnetisation indicates the creation of new functional groups. The BET surface area of MAC was determined to be 496.2m2g-1. The obtained iodine numbers for AC and MAC were 523.59 mg g-1 and 324.96 mg g-1, respectively. The pH at PZC of the synthesised MAC was 4.4. This study suggests that MAC is a sustainable and cost-effective adsorbent for removing contaminants from industrial effluents.