فهرست نشریات علمی دسترسی آزاد ایران

A nanostructured hydroxyapatite functionalised with chitosan and glutamic acid (n-HAp–Cs–Glu) was prepared via a wet-precipitation route and probed as a dual-purpose material for water remediation and microbial control. Beyond the basic XRD, FTIR, FESEM, TEM and BET data reported earlier, additional characterisation by atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis was carried out to confirm the nano-scale character and chemical integrity of the composite. The mean crystallite size dropped from 16.65 nm for pristine n-HAp to 12.27 nm after functionalisation, with AFM giving a mean particle diameter near 60 nm. The composite was then tested for Cd(II) uptake from aqueous solutions while varying contact time, dose, pH, initial concentration and temperature. Equilibrium was reached within 75 min and the kinetics were well described by the pseudo-second-order model (R² = 0.9998), pointing toward a chemisorption-controlled process. Equilibrium data fitted the Langmuir isotherm better than Freundlich, with a maximum capacity of 48.54 mg g⁻¹ at 45 °C and separation factors RL well below unity. Thermodynamics were spontaneous (ΔG° < 0), endothermic (ΔH° > 0) and entropy-driven (ΔS° > 0). Antimicrobial assays showed no zone of inhibition against S. aureus or E. coli, but clear activity against the yeasts C. tropicalis and C. albicans, with a maximum inhibition diameter of 8.5 mm at 1000 mg L⁻¹. The findings highlight n-HAp–Cs–Glu as an inexpensive, eco-friendly nano-adsorbent that is also selectively antifungal.