فهرست نشریات علمی دسترسی آزاد ایران

The escalating release of synthetic dyes, like crystal violet (CV), into water bodies has triggered significant environmental and health worries due to their toxic nature, stability, and long-lasting presence. This research explores the creation, analysis, and adsorption capabilities of a new sodium alginate-g-poly (acrylic acid-co-itaconic acid)/titanium dioxide [SA-g-p(AA-IA)/TiO2] hydrogel nanocomposite for effectively eliminating CV dye from water solutions. The composite was produced using free-radical polymerization and underwent detailed characterization via FTIR, XRD, and FESEM, confirming the integration of TiO2 nanoparticles and a highly porous structure. The impact of operational factors such as contact duration, pH level, temperature, initial dye concentration, and the amount of adsorbent used was systematically investigated. The nanocomposite displayed a substantial adsorption capacity of 197.66 mg/g under optimal conditions of pH=10 and reached equilibrium within 90 min. Kinetic analysis demonstrated a strong correlation with the pseudo-second-order model (R² = 1), indicating a chemical adsorption mechanism. Adsorption isotherm data aligned with both Langmuir and Freundlich models, suggesting the occurrence of both single-layer and multi-layer adsorption on various surfaces, with a maximum capacity nearing 928 mg/g at 10 °C. Thermodynamic analysis revealed the process to be spontaneous (ΔG = –5.812 kJ/mol) and exothermic (ΔH = –15.737 kJ/mol) with a reduction in system entropy (ΔS = –34.255 J/mol·K). The composite also exhibited notable pH-sensitive swelling behaviour, reaching a maximum of 1155 % at pH=12. These findings highlight the SA-g-p(AA-IA)/TiO2 nanocomposite as a highly effective adsorbent for removing CV dye from water systems.