Arsenate Adsorption from Aqueous Solutions Using Chitosan/Fe‐Nanoparticles Composite Microspheres

AbstractThe adsorption behavior and synthesis of a chitosan microsphere composite with iron nanoparticles (Ch‐Fe) for the removal of arsenates [As(V)] from aqueous solutions were investigated. First, the chitosan microspheres (Ch‐SD) were obtained using the Spray Dryer volatilization technique (SD), optimizing their particle size. Then, the iron nanoparticles (Fe‐NPs) were prepared using the microwave precipitation technique. The composite was characterized, and the arsenate adsorption parameters were determined through batch‐type experiments. Significantly fast adsorption rates were observed for both adsorbents. Besides, Ch‐Fe and Ch‐SD effectively removed arsenates over a wide pH range. The hydroxyl and amino functional groups are involved in removing arsenates. The Pseudo‐second order and the Elovich models described arsenate kinetic sorption data for Ch‐Fe and Ch‐SD, respectively. The As(V) maximum adsorption capacities were 27.46 mg/g and 29.94 mg/g for Ch‐SD and Ch‐Fe, respectively, increasing significantly at elevated temperatures. The Langmuir‐Freundlich model adequately described the isothermal data for both materials, suggesting adsorption heterogeneity. The composite's surface impregnation with Fe‐NPs enhanced the Ch‐SD adsorption properties. The SD method was suitable for obtaining the chitosan/Fe‐NPs microspheres and effectively removed As(V) from aqueous solutions.