The reactive surface of Castor leaf [Ricinus communis L.] powder as a green adsorbent for the removal of heavy metals from natural river water

► The Castor leaf powder presented a reactive surface which enables metal ions adsorption through chemisorption process. ► The predominance of macroporous enables water diffusion and metal ions may be adsorbed inside the pores. ► The Castor leaf powder was used in the removal of metal species from river water. ► An enrichment factor of 45 enable the determination of Cd(II) and Pd(II) ions. ► Method validation was performed through an analysis of certified water standards.