The present study utilised date palm fibre (DPF) waste residues to adsorb Congo red (CR) dye from aqueous solutions. The features of the adsorbent, such as its surface shape, pore size, and chemical properties, were assessed with X-ray diffraction (XRD), BET, Fourier-transform infrared (FTIR), X-ray fluorescence (XRF), and field emission scanning electron microscope (FESEM). The current study employed the batch system to investigate the ideal pH to adsorb the CR dye and found that acidic pH decolourised the dye best. Extending the dye-DPF waste mixing period at 25°C reportedly removed more dye. Consequently, the influence of the starting dye and DPF waste quantity on dye removal was explored in this study. At 5 g/L dye concentration, 48% dye removal was achieved, whereas at low dye concentrations, only 40% of the dye was removed. The current study also evaluated the DPF particle size created for dye adsorption, yielding a 66% optimal powder size removal. The heat impact assessment performed in this study indicated that increased temperature affected the amount of dye eliminated from aqueous solutions, where a 72% removal was recorded at 45°C. The pseudo-first- and pseudo-second-order models were utilised to predict the maximum CR dye adsorption with DPF waste. Resultantly, the Langmuir-Freundlich experimental DPF waste CR adsorption documented pseudo-second-order kinetics. In a fixed bed reactor, the DPF waste has been reported to remove CR dye constantly. Consequently, several factors affecting the removal process, including the effects of primary dye, the flow rate of the liquid inside the column, the depth of the filling inside the column, and flow rate were assessed. The results were simulated in the COMSOL® program and compared to practical experiments, which yielded a 99% match. Conclusively, DPF waste could remove several colours from wastewater via active removal.
