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.