Preparation of Corn Stalk Charcoal Composite Film and Study on Its NH3 Adsorption Performance

Abstract

This study utilized corn stover as the biomass feedstock to produce stover charcoal (CC) through modification with oxalic acid. The charcoal was then composited with polyvinylidene fluoride (PVDF) using a coating-crosslinking method, resulting in CC/PVDF composite membranes. By optimizing key parameters including crosslinking agent concentration, crosslinking time, and charcoal loading, a composite membrane with outstanding ammonia adsorption performance was obtained. The membrane’s morphology, chemical composition, and mechanical properties were characterized by scanning electron microscopy, infrared spectroscopy, and a universal testing machine. The results indicate that the optimal ammonia adsorption capacity of 40.4 mg/cm² was achieved under the following conditions: a binder ratio of 1 : 2, a crosslinking agent concentration of 3%, and a crosslinking time of 90 min. After regeneration with ethanol, the membrane retained 69.3% of its initial ammonia adsorption capacity. Furthermore, compared to the original stover charcoal, the composite membrane surface incorporated additional oxygen-containing functional groups (e.g., carboxyl and hydroxyl groups), which contributed to its enhanced ammonia adsorption and removal.