Acacia crassicarpa bark is one of the abundant biomass in Riau Province and is used as raw material for adsorbent in powder form in this study to adsorb Pb(II) ions from aqueous solutions. Acacia crassicarpa bark samples were obtained from Industrial Plantation Forests in Pelalawan Regency, Riau Province. The samples were washed with distilled water, dried in the sun for ±7 days, ground, sieve…