The Effects of Particle Size on the Adsorption of Metaldehyde by Oil Palm Kernel Biochar and Rice Husk Biochar

Metaldehyde contamination poses risks to the environment and public health. Biochar, a carbon-rich material, is recognized for its potential to adsorb water pollutants. This study assesses the effectiveness of oil palm kernel biochar (OPKB) and rice husk biochar (RHB) in removing metaldehyde, considering particle sizes, initial concentrations, and contact times. Smaller biochar particles show increased adsorption sites with a porous structure, while larger particles have fewer active sites, impacting their efficiency. BET analysis reveals that the smallest biochar particles have higher specific surface areas ranging from 72.49 m2/g to 123.08 m2/g. OPKB1 proves to have the most effective adsorption capacity across all conditions. The experimental data are more consistent with the Freundlich isotherm model, which suggests that the active sites are not evenly distributed. The correlation coefficient (R2) value indicates that the adsorption process is governed by pseudo-second-order kinetics.