A method is presented for surface encapsulation of nano-Fe3O4 by o-phenylenediamine via cross-linking using formaldehyde and glutaraldhyde for the formation of two newly designed magnetic nano-sorbents. These have been characterized by FT-IR, TGA, and SEM and maintained the magnetic and thermal stability characters. The metal capacity values of Pb(II) and Cd(II) have been optimized in presence of different physico-chemical parameters and confirmed the superior selectivity for Pb(II). Maximum capacity values of Pb(II) (7000-10000 +/- 250-675 mu mol g(-1)) and Cd(II) (1500-2250 +/- 30-75 mu mol g(-1)) at optimum conditions and excellent extraction values (94.10-100.0 +/- 1.2-3.5%) from industrial wastewater have been identified.