A Novel Interpenetrating Polymer Network Hydrogel Based on Chitosan, Sodium Polyacrylate, and Halloysite Nanoclay for Efficient Pollutant Removal from Wastewater

This study primarily focuses on the development and characterization of a novel nanohybrid interpenetrating polymer network hydrogel composed of chitosan, sodium polyacrylate, and halloysite nanotubes (CS-SA-Hal), designed for potential application in wastewater treatment. This research was motivated by the increasing interest in advanced biomaterials capable of effectively removing contaminants from aqueous media. The synthesized hydrogel was thoroughly characterized using various analytical techniques, including Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Thermal Gravimetry (DTG), and Scanning Electron Microscopy (SEM), to elucidate its structural, thermal, and morphological properties. The results confirmed the successful incorporation of halloysite nanotubes within the polymeric matrix, contributing to the formation of a robust, interpenetrating network. Swelling experiments revealed that the CS-SA-Hal hydrogel exhibited a high swelling capacity of approximately 300%, indicating a highly crosslinked network with significant interstitial porosity. This structural feature is expected to enhance the hydrogel’s sorption properties, making it a promising candidate for environmental remediation applications. To evaluate its efficacy in wastewater treatment, the adsorption performance of the hydrogel was tested against methyl green, a representative organic dye pollutant. Remarkably, adsorption equilibrium was achieved within 5 min, and the maximum adsorption capacity under optimized conditions reached 6840 mg/g, demonstrating superior uptake performance. Kinetic and isotherm modeling revealed that the adsorption process is best described by the Freundlich isotherm model, suggesting multilayer adsorption on a heterogeneous surface. These findings highlight the potential of the CS-SA-Hal nanohybrid hydrogel as an efficient and fast-acting adsorbent for dye removal from wastewater.