Preparation and Characterization of Sodium Chlorite Microcapsules for Formaldehyde Scavenging: Applications in Environmental Control

Abstract This study aimed to develop a functional additive to reduce the release of formaldehyde in wood-based panel products. Sodium chlorite microcapsules, capable of releasing chlorine dioxide, were prepared using sodium alginate/ethyl cellulose as shell materials and sodium chlorite as the core material. The preparation process employed the ionic gel-solvent evaporation method. Influencing factors, such as the mass ratio of sodium chlorite to ethyl cellulose, the emulsifier content, and the mass fraction of sodium alginate, were systematically varied to optimize the microcapsule preparation process. The evaluation index of coverage rate was utilized for optimization. The optimum preparation process was determined as follows: a mass ratio of 2.44:1 for sodium chlorite to ethyl cellulose, an emulsifier dosage of 1.15g, a mass fraction of sodium alginate at 12.52%, resulting in a coverage rate of 63.51%. The formation mechanism was analyzed using various analytical instruments. Fourier transform infrared spectroscopy (FTIR) revealed characteristic absorption peaks of sodium chlorite, sodium alginate, and ethyl cellulose in the microcapsule spectrum. Thermogravimetric analysis (TG-TGA) indicated that the residual content of microcapsules surpassed that of the shell material, ethyl cellulose, suggesting higher thermal stability. Additionally, the weight loss rate of microcapsules at 120℃ was lower, meeting the requirements for the hot-pressing process of wood-based panels. Observation under an optical microscope (OM) and scanning electron microscope (SEM) confirmed microcapsules with an average particle size of 58.71 ± 9.35µm, displaying uniform distribution and distinct surface folds.