Development of bifunctional catalysts synthesized from pyrolyzed and hydrothermalized palm waste for biodiesel production using waste cooking oil
The abundance of waste biomass from palm oil industries creates a new potential for producing activated carbon as catalyst support. The hydrothermal carbonization (HTC) process provides a brilliant alternative to produce activated carbon from biomass samples with higher water content than conv...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2021
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/103801/1/ITMA%202022%2011%20IR.pdf |
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| Summary: | The abundance of waste biomass from palm oil industries creates a new potential for
producing activated carbon as catalyst support. The hydrothermal carbonization (HTC)
process provides a brilliant alternative to produce activated carbon from biomass samples
with higher water content than conventional pyrolysis techniques. Therefore, this study
aims to produce activated carbon from palm kernel shell (PKS), mesocarp fiber (MF)
and empty fruit bunch (EFB) using pyrolysis and HTC techniques. The HTC process
favours the breakage of large polymeric molecules in the lignocellulosic material into
lower molecular weight organic compounds through hydrolysis, dehydration,
decarboxylation, aromatization and recondensation process. Subsequently, the
performance of the prepared activated carbon was determined through the application as
catalyst support of a bifunctional catalyst. Therefore, the activated carbon was
impregnated with K2CO3 and CuO via wet impregnation provided bifunctional
characteristics. The state-of-the-art characterization of the synthesized bifunctional
catalysts was conducted including N2 adsorption-desorption analysis, functional group
determination, surface morphology observation, crystallography study, electron
dispersive X-ray mapping, elemental distribution analysis, concentration of basicity and
acidity measurement and thermal degradation behaviour analysis. The results show that
the HTC technique successfully produced a highly mesoporous activated carbon derived
from PKS that had better textural properties than pyrolyzed with a BET surface area of
1411.16 m2
g-1 and 3368.60 m2
g-1, respectively. The produced bifunctional catalyst was
applied in the simultaneous esterification and transesterification reaction from the waste
cooking oil (WCO) by the conventional reflux system. The high BET surface area
provides extra space for active sites impregnation which is very important for producing
maximum biodiesel yield from WCO. The catalytic performance results show that the
hydrothermalized-activated carbon from PKS (PKSHAC) derived catalyst produced a
higher biodiesel yield of 95.3% against 95.0% over the pyrolyzed-activated carbon from
PKS (PKSAC) derived catalyst. The activated carbon preparation was continued using
MF and EFB, namely hydrothermalized-activated carbon from MF (MFHAC) and EFB
(EFBHAC), which exhibited a BET surface area of 3909.33 m2
g-1 and 4056.17 m2
g-1, and produced a maximum biodiesel yield of 96.4% and 97.1%, respectively. The
synthesized catalysts sustained up to 5 reaction cycles with more than 80% of biodiesel
yield. The carbon structure collapsed due to multiple calcination during the reactivation
procedure, and the catalyst poisoning by glyceroxide on the catalyst surface was
identified as a deactivation factor. On the other hand, the transformation of biodiesel
from WCO was confirmed via proton nuclei magnetic resonance (1H NMR), Fourier
transform Infrared (FTIR) and thermal gravimetric analysis (TGA). Fuel properties
revealed kinematic viscosity of 3.3 mm2
s-1, the cetane number of 51, the flashpoint of
160.5 °C, cloud and pour point of 11 °C and -3 °C, respectively. Overall, the finding
shows the excellent potential of waste materials, especially PKS, MF, and EFB in
producing high quality activated carbon as catalyst support via pyrolysis and HTC
techniques. The functionalization with K2CO3 and CuO via wet impregnation provides
bifunctional that opens the opportunity in utilizing WCO to produce high-quality biodiesel. |
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