Modified Cellulose Nanocrystals for Effective Pesticide Removal from Model Wastewater

Abstract

Cellulose nanocrystals (CNCs) are a renewable and biodegradable emerging nanomaterial obtained by acid hydrolysis having high surface area, abundant hydroxyl groups, and strong dispersibility. The combination of CNCs with spinel ferrite nanoparticles could produce such composites with excellent features and enhanced performance for environmental applications. Therefore, the aim of this work is to synthesize a stable, sustainable photocatalyst for imidacloprid (IMI) degradation from the model wastewater by synthesizing Zn0.3Co0.7Fe2O₄ nanoparticles using the sol-gel method and then incorporating CNC to create a novel photocatalyst CNC@Zn0.3Co0.7Fe2O₄. Characterizations were conducted with Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-VIS spectroscopy. The FTIR results exhibit the CNC blending with ferrite nanoparticles through intermolecular bonding. The XRD pattern shows the CNC@Zn0.3Co0.7Fe2O₄ crystallinity, which is similar to that of pure CNC and pure Zn0.3Co0.7Fe2O₄, indicating successful blending stability. The SEM images reveal an interconnected porous microstructure with Zn0.3Co0.7Fe2O₄ nanoparticles evenly dispersed within the CNC matrix. The UV-VIS results confirm the changes in electronic properties of the synthesized photocatalyst. The photocatalyst CNC@Zn0.3Co0.7Fe2O₄ shows effective photocatalytic degradation ability to degrade IMI from model wastewater under UV light, indicating the applicability of this photocatalyst for environmental remediations. The optimal conditions, using box-Behnken design, were pH 6, catalyst 22.5 mg, 112.5 µL hydrogen peroxide, IMI concentration of 50 mg/l and reaction time 10 minutes to achieve 97.95% degradation efficiency. The photocatalyst shows promising reusability in three successive runs.