Different carbonization process of bamboo charcoal using Gigantochloa Albociliata S. S. M. Isa, M. M. Ramli, D. S. C. Halin, N. A. M. Anhar, and N. A. M. A. Hambali
Citation: AIP Conference Proceedings 1885, 020226 (2017); doi: 10.1063/1.5002420 View online: http://dx.doi.org/10.1063/1.5002420 View Table of Contents: http://aip.scitation.org/toc/apc/1885/1 Published by the American Institute of Physics
Different Carbonization Process of Bamboo Charcoal Using Gigantochloa Albociliata S S M Isa1,2 a), M M Ramli1,2, D S C Halin2,b), N A M Anhar1 and N A M A Hambali1 1
School of Microelectronic Engineering, Universiti Malaysia Perlis, Pauh Putra Campus, 02600, Arau, Perlis, Malaysia 2 Center of Excellence Geopolymer and Green Technology, School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), P.O. Box 77, D/A Pejabat Pos Besar, 01000, Kangar, Perlis, Malaysia a)
Corresponding author:
[email protected], b)
[email protected]
Abstract.Bamboo charcoal has attracted a lot of interests due to their microporous structure, high surface area and great adsorption properties. Some of the applications utilizing this material focused on these advantages such as water purification, electromagnetic wave absorber and blood purification. However, these advantages really depend on the carbonization and activation process of bamboo charcoal. The production must be carried out in properly control environment with precise temperatures and timing. This paper report the production of bamboo charcoal using Gigantochloa Albociliata in controlled environment at 500 °C for 1 hour (lab-prepared). Then the material was characterized for their dispersibility and adsorption behaviour. Furthermore, the bamboo charcoal that was produced commercially, by company, was also characterized and compared. The results show, bamboo charcoal produced by lab-prepared has similar qualities with the commercial bamboo charcoal.
INTRODUCTION Bamboo is among the fastest growing plant in the world where most of the population can be found in South Asia, Southeast Asia and East Asia including Malaysia. Through pyrolysis of bamboo in the absence of air, bamboo charcoal can be obtained. For carbonization process, the process normally takes place under temperature of 400 °C up to 800 °C either using underground traditional method, mechanical kiln or furnace. In another hand, activation process can be done either by thermal or chemical reactions. Thermal treatment can be done in the range of 600 °C to 1200 °C where no chemical used. For chemical treatment, the charcoal is saturated with chemicals like acids, bases or salts such as phosphoric acid, potassium hydroxide and zinc chloride before annealed under temperature of range of 450 °C to 900 °C [1]. Recently, bamboo charcoal which has special microporous structure has attracted great attention. Compared to wood charcoal, charcoal from bamboo are four times more cavities, three times more mineral content and four times better adsorption rate. While in terms of surface area, bamboo charcoal which has 300 m 2g-1 is ten times greater than wood charcoal (30 m2g-1) and larger than multi-walled carbon nanotubes (200 m2g-1) [2]. Most of the available applications of this bamboo charcoal are usually focused on the effectiveness of its absorption properties like absorbent in water purification [3], electrode in dye sensitized solar cell [4], electromagnetic waves absorber in telecommunication devices, application in blood purification [5] and others. The applications of bamboo charcoal are really depends on the carbonization and activation process of the bamboo. These processes may affect the structural properties like surface area and pore volumes, adsorption
3rd Electronic and Green Materials International Conference 2017 (EGM 2017) AIP Conf. Proc. 1885, 020226-1–020226-6; doi: 10.1063/1.5002420 Published by AIP Publishing. 978-0-7354-1565-2/$30.00
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capabilities and also conductivity. Zuo et. al. [6] in his work has informed that the mechanism of carbonization is really important as the process will affect the main elements of carbon, hydrogen and oxygen as well as reactivity of various groups composed of these atoms. In this study, carbonization process of Buluh Madu or Gigantochloa Albociliata as shown in Fig. 1 was done in two different methods; mechanical kiln (commercial sample) and furnace chamber (lab-prepared). The structural properties and absorbability of the prepared bamboo charcoal will be further analyzed between commercial bamboo charcoal and lab prepared sample.
FIGURE 1. (a) Buluh Madu or Gigantochloa Albociliata, (b) Bamboo charcoal
EXPERIMENTAL PROCEDURES The Buluh Madu (Gigantochloa Albociliata) in the age ranging between 2-4 years was used as the main sample to prepare bamboo charcoal. The bamboo culm was cleaned and chopped into segments, 3 cm x 10 cm and the moisture content is kept at 10 %. For bamboo charcoal production, two methods were applied; 1) mechanical kiln at temperature of 400 to 550 °C for 4 to 6 hours which was done by selected manufacturer and later was named as BCA; and 2) carbonization process using furnace prepared in Failure Analysis Lab, School of Microelectronic Engineering, UniMAP. The lab sample was prepared by carbonized the bamboo at 500 °C in nitrogen atmosphere for 1 hour and named as BCB. In order to investigate the dispersibility of the prepared sample, bamboo charcoal was prepared in de-ionized (DI) water and ethanol at different concentrations. Then, the morphological and structural properties of bamboo charcoal were analyzed using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The absorption ability for both samples was characterized using Ultra-Violet Visible (UV Vis) spectroscopy.
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RESULTS
FIGURE 2. (a) Bamboo charcoal solution at the concentration of 0.7 mg/mL and 2.5 mg/ml in ethanol. (b) Physical state after 3 months preparation time.
Bamboo charcoal solution was prepared at two concentrations of 0.7 mg/mL and 2.5 mg/mL in ethanol and DI water. Well dispersed solutions were produced and the stability of these solutions was observed after 3 months. Figure 2 shows the state of bamboo charcoal solution at two different concentrations in ethanol and the solubility of the same solution after 3 months prepared. The color of the solution becomes brighter but only small amount of bamboo charcoal was swamped to the bottom of vial. The results show that the solution prepared in ethanol shows better dispersibility compared to DI water. The structural properties of BCA and BCB were examined under SEM at the same magnification as shown in Fig. 3. At 500 °C, it was observed that the bamboo charcoal particles were in spherical shapes. However, the particle sizes of BCA (~ 43.1 nm) was 39.9 % larger compared to the BCB (~ 25.9 nm). This is believed due to BCA particles have started to coalescence and agglomerate between each other. The BCB particles are more individual and the size of the particles is even.
FIGURE 3. SEM images of (a) BCA (b) BCB.
Figure 4 shows the FTIR spectra of BCA and BCB at the concentration of 0.7 mg/mL. A broad peak at 3420 cm-1 was obtained for BCB compared to BCA correspond to the weak carboxylic group (stretching vibration of
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O-H groups). As the carbonization or activation temperature increases, it was expected that this peak will decrease as the sample will be dehydrated. Peak at 2942 cm-1 was ascribed for both samples due to the presence of C-H sp3 of the cellulose. Compared to BCB sample, peak at 1648 cm-1 was obtained for BCA sample correspond to the strong C=C stretching and carbonyl stretching adsorption (C=O). Then, a very small peak due to the O-H bending was observed at 1424 cm-1 for both samples. A very sharp peak at 1030 cm-1 is shown for BCA and BCB samples correspond to the stretching of C-O and O-H bending. The final peak was observed at 834 cm-1 due to bending of CH adsorption in aromatic rings . TABLE 1. FTIR spectrum of bamboo charcoal.
Band position, cm-1 3420 2492 1648 ʋ, stretching
Assignment Band position, cm-1 Assignment ʋ O-H 1424 ɓ O-H ʋ C-H 1030 ʋ C-O, ɓ O-H ʋ C=C, ʋ C=O 834 γ C-H ɓ, bending in plane γ, bending out of plane
FIGURE 4. FTIR spectrum of (a) BCA (b) BCB.
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The absorption property of these two samples was investigated at three different concentrations 0.2 mg/mL, 0.4 mg/mL and 0.7 mg/mL as shown in Fig. 5. For both samples, the peak was observed at around 292 nm and slightly shifted to the right as the concentration increased. As the concentration increases, the adsorption of the solution also increases.
FIGURE 5. UV Vis Graph of (a) BCA (b) BCB.
CONCLUSION Two carbonization methods which were mechanical kiln and furnace have successfully done in order to produce bamboo charcoal from Malaysia Buluh Madu. The grinded bamboo charcoal was prepared in ethanol and DI water to investigate dispersibility and stability of the sample. The results show that the solution in ethanol was much more stable compared to DI water. The SEM images show that the particles of bamboo charcoal prepared by mechanical
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kiln process was much larger compared to the lab furnace as the particle start to coalesce between each other. FTIR spectrum shows the functional groups of the samples which are comparable to other reported results. Both samples show similar adsorption property where the similar peak was obtained and the adsorption was increased as the concentration increases. As a conclusion, the lab prepared sample has a similar quality compared to the commercialized product. ACKNOWLEDGMENTS This work was partially supported by Fundamental Research Grant FRGS No. 9003-00532), funded by Ministry of Higher Education (MOHE), Government of Malaysia and JitraGro Resources Industry. REFERENCES 1. 2. 3. 4. 5. 6.
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