Mesoporous activated carbon produced from coconut shell using a single-step physical activation process
In this work, the pore properties and textural characterization of resulting activated carbons (ACs) derived from dried coconut shell (DCS) were investigated in duplicate using a single-step physical activation process. Based on the thermochemical properties of DCS analyzed, the process features its carbonization temperature of 500 °C at a constant heating rate of 10 °C/min under nitrogen flow, subsequently switched to the gasification with CO2 gas in the ranges of 700–900 °C (activation temperature) and 0–60 min (holding time) in the same reactor. The results showed that the pore properties (including mesoporosity) of resulting AC products, obtained from nitrogen adsorption-desorption isotherm and true density measurements, were on an increasing trend as activation temperature and holding time increased. These findings were attributable to the severe reactions of the lignocellulose-based char with CO2. According to the maximal Brunauer-Emmet-Teller (BET) surface area (˃ 1100 m2/g) and mesoporosity percentage (˃ 40%), the optimal activation conditions should be performed at 850 °C for a holding time of 60 min, but will result in relatively low yield. Furthermore, the textural structures and elemental compositions of DCS-based ACs were viewed using the scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS) and elemental analysis, showing consistent results as described above.
KeywordsActivated carbon CO2 activation Coconut shell Pore property Mesoporosity
Sincere appreciation was also expressed to acknowledge the Instrumentation Centers at National Chung Hsing University and National Pingtung University of Science and Technology for the assistances in the elemental analysis (EA) and SEM-EDS observation, respectively. On the other hand, we also thank Prof. K.C. Chen (Department of Environmental Science and Engineering, National Pingtung University of Science and Technology) for his assistance in this work.
The authors are grateful for funding supports from the Ministry of Science and Technology of Taiwan (grant no. MOST 105-2622-E-020-004-CC3) and Li-Jing Viscarb Co. (Pingtung, Taiwan).
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