Engineering Porosity-Tuned Chitosan Beads: Balancing Porosity, Kinetics, and Mechanical Integrity

Chitosan, a cationic natural polysaccharide derived from the deacetylation of chitin, is known for its solubility in diluted acidic solutions, biodegradability, biocompatibility, and non-toxicity. This study introduces three innovative methods to prepare porous chitosan microsphere particles, which are crucial for enhancing their efficiency in water remediation and medical applications. The methods, solvent extraction, surfactant extraction, and substance decomposition, involve the integration and subsequent extraction or decomposition of materials during the synthesis process, eliminating the need for additional steps. We used state-of-the-art characterization techniques to analyze and evaluate the chemical and physical properties of the particles, such as Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and especially three-dimensional computed tomography (CT) scanning. The CT scans were used to visualize and measure the porosity of different particle types, ranging from 68.4% to 39.3%. This detailed study extended to evaluate the mechanical properties of the particles under compressive forces in wet and dry conditions, highlighting the influence of porosity on their mechanical integrity and compression pressure behavior. In addition, we explored the adsorptive properties of these chitosan particles, using methylene blue as a model pollutant because of its toxicity, underscoring the significance of porosity in enhancing their pollutant removal efficiency. This study opens the window for developing environmentally sustainable polymer particles and highlights the pivotal role of porosity in optimizing the material’s efficacy for a wide range of applications.