Volume 14, No. 3, April 2014, Pages 916-927 PDF(3.13 MB)
Facile Preparation of Nitrogen-Doped Activated Carbon for Carbon Dioxide Adsorption
Lung-Chuan Chen1, Po-Yang Peng2, Long-Full Lin3, Thomas C.K. Yang2, Chao-Ming Huang1
1 Department of Materials Engineering, Kun Shan University, 949 Da Wan Road, Tainan 71003, Taiwan
2 Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 1 Section 3 ZhongXiao East Road, Taipei 10608, Taiwan
3 Department of Environmental Engineering, Kun Shan University, 949 Da Wan Road, Tainan 71003, Taiwan
- N-doped activated carbons were prepared by amination after nitric acid oxidation.
- The pre-oxidation of ACs enhanced the N incorporation during the amination process.
- The amination of oxidized AC at 700°C (NORF700) exhibited the highest CO2 capacity.
- High surface area, pyrindinic and pyrrole N are responsible for activity of NORF700.
Nitrogen-doped activated carbons with high surface areas obtained from resorcinol and formaldehyde resins were evaluated as CO2 adsorbents in a simulated flue gas stream under anhydrous and humid conditions. These carbons were prepared using two approaches, namely ammonia treatment without nitric acid pre-oxidation and amination after pre-oxidation. The pre-oxidation of activated carbons considerably enhanced the nitrogen incorporation during the amination process. The amination temperature affects the content and type of nitrogen incorporated onto the carbon surface, as determined by X-ray photoelectron spectroscopy, which enhances the specific adsorbent-adsorbate interaction for CO2 in humid conditions. The presence of H2O in the feed gas significantly decreased CO2 adsorption for a very low nitrogen content of virgin activated carbon. A sample prepared via the amination of pre-oxidized carbon at 700°C (NORF700) exhibited excellent tolerance to moisture and the highest CO2 capacity of 2.10 mmol/g in a 7% CO2/83% N2/10% H2O wet stream at 50°C and 130 kPa. The high performance of NORF700 was ascribed to its high surface area, adequate micropore volume, and high amounts of pyrindinic-like and pyrrole-like nitrogen species. The results indicate that nitric acid pre-oxidation followed by ammonia treatment at 700°C is an appropriate process for preparing adsorbents for CO2 separation in post-combustion applications.
Activated carbon; Ammonia treatment; CO2 adsorption.