Chitosan-integrated TiO2 nanocomposite for adsorptive removal of Cd and Pb from drinking water

This work described a plant extract-based synthesis of titanium oxide nanoparticles (D-TiO₂–NPs) using Duranta erecta leave extract, followed by the fabrication of its nanocomposite (D-TiO₂–NC) with chitosan for adsorptive removal of toxic metals (TMs) cadmium (Cd) and lead (Pb) from water. D-TiO₂–NPs and D-TiO₂–NC were characterized by various analytical techniques. This study confirmed the porous and rough crystalline nanostructure with different functional groups of chitosan and D-TiO₂–NPs of synthesized D-TiO₂–NC for feasible excellent adsorptive removal of Cd and Pb. The maximum removal of Cd and Pb was achieved at pH (6), initial concentration of metal ions (30 mg L⁻¹), the content of D-TiO₂–NC (50 mg), contact time (30 min), and temperature (45 °C) with adsorption capacities of 147 and 145.5 mg g⁻¹, respectively. The D-TiO₂–NC has successfully followed the pseudo-second-order kinetics for the successful removal of Cd and Pb. However, the resulting data followed multilayer adsorption for the removal of Cd while monolayer adsorption for Pb onto the D-TiO₂–NC. The findings of the thermodynamic study revealed that the D-TiO₂–NC followed the endothermic and spontaneous adsorption process for the adsorption of Cd and Pb. Furthermore, D-TiO₂–NC can easily be used several times after washing with diluted HNO₃ for the adsorptive removal of Cd and Pb. Moreover, it is quantitatively adsorbed (> 90%) the Cd and Pb from the collected drinking water samples.

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