부산대학교 도서관

Here, a novel nitrogen-doped carbon nano-material (N-CGNM) with hierarchically porous structure was prepared from spent cofee ground for efcient adsorption of organic dyes by a simple one-step carbonization process (the uniform mixture consists of spent cofee ground, urea, and CaCl2 with the ratio of 1:1:1, which was heated to 1000 °C with a rate of 10 °C min−1 and held at 1000 °C for 90 min in N2 atmosphere to carry out carbonization, activation, and N-doping concurrently). The morphology and structure analysis show that the prepared N-CGNM exhibits hierarchical pore structure, high specifc surface area (544 m2 /g), and large numbers of positively charged nitrogen-containing groups. This unique structure and chemical composition endow N-CGNM with an excellent adsorption capacity toward anion Congo red (623.12±21.69 mg/g), which is obviously superior to that (216.47±18.43 mg/g) of untreated spent cofee ground-based carbon nano-materials (CGM). Oppositely, the adsorption capacity of N-CGNM towards cation methylene blue is inferior to that of CGM due to the existence of electrostatic repulsion. These fndings show a great guidance for the development of low-cost but efcient selective adsorbent.