TY - JOUR
T1 - Formation of hollow carbon nanofibers on bio-char during microwave pyrolysis of palm kernel shell
AU - Omoriyekomwan, Joy Esohe
AU - Tahmasebi, Arash
AU - Zhang, Jian
AU - Yu, Jianglong
N1 - Funding Information:
This study was supported by the National Natural Science Foundation of China (21676132). The authors also acknowledge the financial support of other grants funded by National Natural Science Foundation of China (21476100, U1361120, and 21176109). The PhD scholarship from the Liaoning Provincial Government of China is gratefully acknowledged.
Publisher Copyright:
© 2017
PY - 2017/9/15
Y1 - 2017/9/15
N2 - Hollow carbon nanofibers (HCNFs) were found to have formed during microwave pyrolysis of palm kernel shell (PKS) at 500 and 600 °C. The formation of HCNFs was only observed during microwave pyrolysis and not the fixed-bed pyrolysis, indicating that microwave played a key role in formation of HCNFs. X-ray diffraction (XRD) analysis of microwave bio-chars showed typical carbon diffractions at 2θ = 26.3° and 43.2°, indicating good graphitic structure of HCNFs, especially for bio-chars prepared at 600 °C. High resolution transmission electron microscope (HRTEM) results revealed multiwall nature of the HCNFs with carbon layer spacing of 0.34 nm. Two major tubular and bamboo-shape structures were observed for HCNFs. With increasing microwave pyrolysis temperature from 500 to 600 °C, the yield of HCNFs increased from 5.85 wt.% to 9.88 wt.%. Raman spectroscopy analysis showed that with increasing pyrolysis temperature to 600 °C, the ID/IG ratio decreased from 0.95 to 0.86, indicating higher order of the carbon layers of the HCNFs. Energy dispersive X-ray spectroscopy (EDS) showed the presence of Fe, K, and Ca in HCNFs structure which may have played a catalytic role during their formation and growth. Mechanism of formation and growth of HCNFs under microwave irradiation were proposed and discussed. The HCNFs-coated bio-char has great potential for removal of heavy metals from waste water.
AB - Hollow carbon nanofibers (HCNFs) were found to have formed during microwave pyrolysis of palm kernel shell (PKS) at 500 and 600 °C. The formation of HCNFs was only observed during microwave pyrolysis and not the fixed-bed pyrolysis, indicating that microwave played a key role in formation of HCNFs. X-ray diffraction (XRD) analysis of microwave bio-chars showed typical carbon diffractions at 2θ = 26.3° and 43.2°, indicating good graphitic structure of HCNFs, especially for bio-chars prepared at 600 °C. High resolution transmission electron microscope (HRTEM) results revealed multiwall nature of the HCNFs with carbon layer spacing of 0.34 nm. Two major tubular and bamboo-shape structures were observed for HCNFs. With increasing microwave pyrolysis temperature from 500 to 600 °C, the yield of HCNFs increased from 5.85 wt.% to 9.88 wt.%. Raman spectroscopy analysis showed that with increasing pyrolysis temperature to 600 °C, the ID/IG ratio decreased from 0.95 to 0.86, indicating higher order of the carbon layers of the HCNFs. Energy dispersive X-ray spectroscopy (EDS) showed the presence of Fe, K, and Ca in HCNFs structure which may have played a catalytic role during their formation and growth. Mechanism of formation and growth of HCNFs under microwave irradiation were proposed and discussed. The HCNFs-coated bio-char has great potential for removal of heavy metals from waste water.
KW - Bio-char
KW - Carbon structure
KW - Hollow carbon nanofibers
KW - Microwave irradiation
UR - http://www.scopus.com/inward/record.url?scp=85020764240&partnerID=8YFLogxK
U2 - 10.1016/j.enconman.2017.06.022
DO - 10.1016/j.enconman.2017.06.022
M3 - Article
AN - SCOPUS:85020764240
SN - 0196-8904
VL - 148
SP - 583
EP - 592
JO - Energy Conversion and Management
JF - Energy Conversion and Management
ER -
