Simultaneous Adsorption of Chromium, Nickel, and Phenol from Landfill Leachate Using Pineapple Residues Biochar

Toxic substances are common in landfill leachate and pose significant risks to the environment and human health. Pineapple residue biochar was used to remove chromium, nickel, and phenol from landfill leachate. This study was to evaluate the adsorption potential of pineapple residue biochar for the removal of chromium (Cr), nickel (Ni), and phenol from landfill leachate. Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) analysis were used to evaluate the pineapple biochar produced. The effects of biochar dose, exposure duration, and initial pollutant concentrations on removal efficacy were evaluated using batch adsorption experiments. The adsorption efficiency of Cr, Ni, and phenol ranged from 99.23% - 99.72%, 98.72% - 99.55%, and 23.62% - 48.03%, respectively. The removal efficiency of greater than 99% for Cr and 98% for Ni by the pineapple residue biochar as an adsorbent proved highly effective. The kinetic study showed pseudo-second-order kinetics had the best fit, with the most R2 values being > 0.90. The FTIR spectra indicate that the pineapple residue biochar contains aromatic, hydroxyl, carbonyl, and carboxylate groups, which were crucial for the adsorption of toxic metals and phenol in the landfill leachate owing to their interactions. The mineral composition of pineapple residue biochar has a significant influence on the adsorption capacity of pollutants in the landfill leachate. The high adsorption efficiency of the pineapple residue biochar is attributed to its lignocellulose content, surface area, the presence of organic functional groups, and mineral content, as regulating mechanisms for effective contaminant adsorption. Further studies should be conducted on the efficiency of pineapple residue biochar in removing other harmful contaminants, emphasising organochlorines.