This study addresses the inherent hydrophobicity of polysulfone (PSF) by developing polysulfone-hydroxyapatite (PSF-HA) composite spheres via phase inversion method, thereby enhancing their potential as metal sorbents for water treatment. The incorporation of hydrophilic hydroxyapatite (HA) nanoparticles significantly improved the material porosity, wettability, and adsorption capacity for cationic heavy metals. Increasing HA loading to 50 wt% (M-50HA) optimized performance, reducing the contact angle from 84.89° (pristine PSF) to 39.01° and enhancing porosity by ~2.3-fold. The composite hydrophilicity and surface charge facilitated strong electrostatic interactions with metal ions, enabling efficient adsorption of Pb (II), Cd(II), Ni(II), and Cu(II) simultaneously, in both batch and fixed-bed recirculation column systems. In a quaternary ion mixture, the PSF-HA spheres exhibited pH-dependent selectivity at pH 4, achieving removal efficiencies of 94% Pb(II) > 89% Ni(II) > 81% Cu(II) > 73% Cd(II) under optimized conditions (35 mg/L initial concentration, 60 mL/min flow rate, 8-h contact time). Density functional theory (DFT) calculations revealed that adsorption affinity correlates with metal ion electronic properties: lower energy gaps and strong back-donation energy in Pb(II) and Ni(II) fostered more stable surface complexes, leading to higher adsorption efficiency compared to Cu(II) and Cd(II). This work provides a scalable strategy for designing multifunctional composites with tunable hydrophilicity and high specificity for heavy metals, advancing their potential in wastewater remediation. • Novel Hydroxyapatite-Polysulfone hybrid composites sorbents were synthesized. • Incorporating 50% HA into PSF yielded enhanced the composite's overall properties. • DFT and NCI analysis revealed a synergistic effect enhancing PSF ion binding affinity. • DFT calculations revealed that metal ions preferentially adsorb onto P O, S O, Ca, and OH groups. • Hydrogen bonding, electrostatic interactions, complexation, and ion exchange drove adsorption.
Brahmi et al. (Sun,) studied this question.