Here we presented a functional biochar materials (FBM) with hierarchical porosity derived from bio-waste (soybean cake) by one-step carbonization method at different temperatures (500-800 degrees C). Various functional groups generated from the carbonized soybean cakes are rich in heteroatom elements (O, N, and P) of endosperm and silanol groups of epiderm. The optimized proportion of functional/silanol hybridized groups was observed in FBM-700 (at 700 degrees C) with hierarchical structure, which exhibits highest Pb(II) absorption capacity of 133.6 mg g(-1) at pH = 5. Various functional groups of FBM-700 with hierarchical structure provide efficient active sites and easy-transport ion channels, leading to synergistic effects for high removal capacity of heavy metals ions. This work provides a green, environment-friendly and scale-up method to fabricate biochar-based functional materials from biowaste for the treatment of heavy metal pollution.