Synthesis of fungal chitosan–polystyrene modified by nanoparticles of binary metals for the removal of heavy metals from waste aqueous media

Abstract

The objective of this study was to assess the efficacy of fungal chitosan–polystyrene-Co-nanocomposites (FCPNC) as a material for the adsorptive removal of cadmium (Cd) ions from aqueous solutions. The synthesis and characterization of FCPNC were accomplished using various analytical techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and dynamic light scattering (DLS). The effectiveness of this adsorbent in removing Cd(II) species from solution matrices was systematically investigated, resulting in the achievement of a maximum adsorption capacity of approximately 112.36 mg g⁻¹. This high adsorption capacity was detected using the following operational parameters: solution pH equals 5.0, 60 min as a contact time between the adsorbent and Cd(II) solution, Cd initial concentration of 50 ppm, adsorbent dosage of 0.5 g L⁻¹ and room temperature. The process of cadmium adsorption by FCPNC was found to follow the Langmuir isotherm model, suggesting that a chemical reaction occurs on the biosorbent surface. Kinetic studies have demonstrated that the cadmium removal process aligns well with the pseudo-second-order model. The thermodynamic analysis revealed the following values: ΔH° = 25.89 kJ mol⁻¹, ΔG° = −21.58 kJ mol⁻¹, and ΔS° = 159.30 J mol⁻¹ K⁻¹. These values indicate that the sorption process is endothermic, spontaneous, and feasible. These findings suggest the potential of FCPNC as an exceptionally effective biosorbent for the removal of water contaminants.