Nanoparticles (NPs) modified with proper compounds are now gaining much attention for their function as new adsorbents for environmental remediation. The main objective of this study is to determine the effectiveness of modified nanoparticles (MNPs) as sorbents in removing Cd?2, Cu?2, and Ni?2 from single and competitive solutions by TiO2 NPs modified with humic acid (Ti–H), extractant of Walnut shell (Ti–W), and 1, 5 diphenyl-Carbazon (Ti–C). MNPs were characterized by XRD, FT-IR, and SEM–EDX analyzer. The MNPs were spherical in shape. The mean diameter of MNPs was determined to be 64.7 nm. The sorption of Cd?2 and Cu?2 on MNPs fitted better in Langmuir model than Freundlich model. But Ni?2 sorption better fitted in Freundlich model. Kinetics of adsorption follow pseudo-second order kinetic model than pseudo-first-order kinetic model. The adsorption maximum was observed at pH 7. Adsorption capacities of MNPs were obtained from Langmuir model and final point of isotherm. Comparison with published adsorption capacities for other adsorbents indicated that Ti–W and Ti– C had potential as proper adsorbents for the removal of Cd?2 and Cu?2 from single and competitive aqueous solution and Ti–H was a good candidate for Ni?2 removal from single and competitive solutions.
