Fixed-Bed Column Removal of Cyanide Using Graphene-Type Biochar: Influence of Operating Parameter

Abstract

In this study, graphene-type biochar was synthesized from agricultural waste (oil palm seed shells of the hybrid dura x pisifera variety) and utilized as an adsorbent bed for cyanide removal from synthetic aqueous solutions. The material was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Operational parameters, including column flow rate, initial cyanide concentration, and adsorbent mass, were examined. The Bohart-Adams, Thomas, and Young-Nelson models were applied to the experimental results. The synthesized adsorbent has a low moisture content, high ash content, and a neutral surface charge (pH 7.3). Its iodine number (Id) is 389.21 mg/g, indicating moderate porosity. The models showed that the theoretical saturation (N0) decreases with increasing mass and flow rate while these parameters remain favorable. The theoretical capacity (Q_theo) predicted by the Thomas model rises with both the initial concentration and the adsorbent mass. This study demonstrates the effective elimination of cyanide using the synthesized biochar, with strong predictive capabilities for column operation.