Fusiform CuC2O4 loaded porous biochar derived from phosphoric acid-activated bagasse for gaseous ammonia capture

Ammonia gas (NH3) in a relatively high concentration can cause irreversible damage to the environment and humans. Thus, it is important to develop a highly efficient adsorbent for NH3 removal. In this study, a novel fusiform CuC2O4-loaded bagasse-derived biochar (CuC2O4/BGB) was prepared by a combination of pyrolysis of H3PO4-activated bagasse powder and the co-precipitation method as an efficient adsorbent for NH3 capture. Specifically, the CuC2O4/BGB-2–600–0.7 composite with a specific surface area of 1160.77 m2/g was obtained by optimizing the activator amount, activation temperature, and CuC2O4 loading amount. The CuC2O4/BGB-2–600–0.7 composite delivered static adsorption capacity of 8.68 mmol/g at 298.15 K and 1 bar, and maintained the NH3 adsorption capacity above 6.5 mmol/g after 8 cycles of regeneration. The adsorption of NH3 on the as-prepared composite conformed to the Redlich-Peterson adsorption isotherm model and Fick’s diffusion kinetics. The adsorption mechanism was elucidated that well-developed micro/mesoporous structure provided abundant active adsorption sites, of which the acidic sites on the catalyst surface promoted the formation of NH4+ from NH3, and the complexation reaction between Cu2+ and NH3 formed the [Cu(NH3)4]2+ complex. Therefore, the as-prepared CuC2O4/BGB is an efficient and sustainable adsorbent for NH3 removal, which opens a new window for malodorous gas removal.