Thesis Archive
CNT Production from Acetylene and Biomass Pyrolysis Gases Through MPECVD Method
Jan Patrick G. Si
Mark Angelo T. Tionson
Francis Ian M. Tobias
Abstract:
The production of carbon nanotubes (CNTs) has been a common topic in the field of material science mainly due to its strong potential in the fields of electronics, biotechnology, medicine and manufacturing. In the past, carbon precursors from nonrenewable, petroleum-derived sources have been used to produce high-yield CNTs of varying structures and morphologies. However, other novel sources which do not rely on depleting fossil fuels have not yet been extensively studied. This paper delves into the use of alternative carbon sources from coconut shells, Sargassum Polycystum and rice husks, together with a controlled amount of acetylene (at 60 mL/min), in the synthesis of high
yield CNTs. A simultaneous microwave assisted pyrolysis and microwave plasma enhanced chemical vapor deposition method was employed to synthesize the CNTs. The study compared the effects of varying combinations of carbon sources and microwave power levels 4 (450.4W) , 5 (510W) , and 6 (569.5W) to the CNT yield and properties. The average diameter and aspect ratio of the nanotubes were determined using a scanning electron microscope while the purity and yield of CNTs were measured through thermogravimetric analysis. CNTs of diameters ranging from 32.7nm to 160.8nm and aspect ratios ranging from 2.40nm/nm to 34.80nm/nm were synthesized. Carbon sources
and power levels were determined to have little to no effect on CNT morphology. The yield ranging from 1.25mg CNT/g precursor to 23.46mg CNT/g precursor depended largely on the two factors while purity of about 78% to 87% of the CNT samples across all trials varied with the power levels. Among all samples, rice husks and a power level 5 (510W) were the optimal factors which maximized purity, yield and aspect ratio and minimized CNT diameters. These results would be significant in identifying the parameters for possible production of CNTs from biomass sources and lessen the use of fossil fuels to produce this novel material in the future.
Adviser:
Dr. Joseph Auresenia