Synthesis and characterization of cerium oxide hybrid with chitosan nanoparticles for enhancing the photodegradation of Congo Red dye

Nanoparticles of cerium oxide have great importance in several fields, including great influence on the environment and human health. The preparation nanoparticles of CeO₂ hybrid with chitosan has exhibited promising applications in several fields especially degradation of organic pollutants such as dyes and pesticides. This study illustrated a facile, eco-friendly, and low-cost method for synthesis of pure CeO₂ and its loading on chitosan NPs with different loading ratios. The as-synthesized catalysts were characterized using UV–Vis, XRD, FT-IR, SEM, EDX, and TEM studies. The presence of an intense peak at 215 nm is detected by the spectrum of UV–Vis indicated by the formation of pure CeO₂, where the presence of Ce–O bonds was confirmed by an FT-IR peak at 769.45 cm⁻¹. EDX analysis showed the presence of Ce, O, and C in pure and hybrid CeO₂–chitosan NPs. The SEM graph showed an irregular shape with aggregation of NPs, both CeO₂ and hybrid CeO₂–chitosan NPs. The as-synthesized photocatalysts showed maximum degradation ratios of Congo Red (CR) dye under specified conditions: pH 8, irradiation exposure time = 90 min, catalyst dose = 0.3 g/L, and 50 mg/L CR initial concentration. The Langmuir isotherm model is better fitted than the Freundlich model. Kinetically, the photodegradation reaction is followed the pseudo-second order model with q_e ranging between 43.67 and 46.51 mg/g with R² > 0.99.