Comparative Study of the Extraction of Cu(II) and Fe(II) Ions Using Chitosan and Modified Chitosan/Polyvinylpyrrolidone Adsorptive Membranes: Adsorption, Kinetic, and Thermodynamic Study

The current work examined chitosan's adsorptioncapabilitiesfor removing Cu(II) and Fe(II) ions from the aqueous phase in a batchequilibrium system. The membranes were prepared using the leaching-outmethod. The effects of the adsorbent's initial pH, concentration,temperature, and dose on adsorption were examined. Adsorption testswere conducted at temperatures ranging from 15 to 45 & DEG;C and initialconcentration ranges of 20-400 mg/L. The observations fromthe adsorption isotherms fitted the Langmuir and Freundlich modeladequately. The nonlinear form of the pseudo-first-order model wasfollowed by the kinetics of Cu(II) and Fe(II) on chitosan, and themodel parameters were reliably obtained. The endothermic and spontaneouscharacter of Cu(II) and Fe(II) adsorption on chitosan adsorbents wasverified by the computed negative values of standard Gibbs free energyand positive enthalpy changes. Finally, chitosan (CS) showed to bean efficient adsorbent for the removal of Cu(II) and Fe(II) ions dueto its high adsorption capacity for Cu(II), which was 182.15 mg/gfor C1, 331.28 mg/g for C2, and 384.31 mg/g for C3, and Fe(II), whichwas 201.67 mg/g for C1, 352.53 mg/g for C2, and 315.8 mg/g for C3(where C1 is the CS membrane, C2 is the CS/silica membrane, and C3is the CS/polyvinylpyrrolidone membrane).