Piyawan Thummasorn. Studies of the efficiency of activated carbon prepared from bagasse for the decolorization of syrup in the refined sugar process. Master's Degree(Technology of Environmental Management). Mahidol University. : Mahidol University, 2007.
Studies of the efficiency of activated carbon prepared from bagasse for the decolorization of syrup in the refined sugar process
Abstract:
The objective of this project was to study the efficiency of bagasse-made activated carbon
(BMAC) in the decolorizations of raw sugar syrup in the refined sugar process as compared to the
methods using resin and commercial activated carbon (CAC). The activated carbon was prepared from
the bagasse by burning the raw bagasse in an electric burner with N2 gas at flow rate 1 liter/min, 550 °C
for 20 mins and then activated by burning the resulting coal in a furnace with a mixture of N2 and CO2
gases (70/30% by vol.) at 850°C for 30 mins. The efficiency of BMAC in the decolorization of raw
syrup was studied using various conditions. The conditions used were stirring times of raw syrup added
to BMAC at 10, 20, 30, 40, 50, 60, 70, 80 and 90 min, pH values of raw syrup were adjusted to 4, 6 and
8, amounts of BMAC added to raw syrup were at 0.5, 1.0, 1.5, 2.0 and 2.5 g and particle sizes
of BMAC were at <212 and 212-250 μm.
The results obtained indicated that the optimum pH for decolorization was 8 with the amount
of BMAC at 2.5 g and the stirring time of 60 min. The best particle size of BMAC for decolorization
was at 212-250 μm. The efficiency of decolorization using BMAC was 50.97%, lower than CAC, at
63.08%, by 12.11% and also lower than the efficiency by using resin, at 68.01%, by 17.04%.
It was found that the efficiency of BMAC in the decolorization was different at different pH
values of raw syrup, and the efficiency increased with the stirring times of raw syrup until the optimum
conditions were reached and the efficiency increased with increasing amount of BMAC added to the raw
syrup. These results agree with the hypothesis. However, the efficiency was found to increase with
decreasing particle size of BMAC, and this does not agree with the research hypothesis.
The estimated production cost to prepare the BMAC was 4,932 Baht/kg, while the cost of resin
is about 7,200 Baht/kg. Thus the cost of BMAC is lower than that of the resin. Even though the BMAC
showed lower efficiency than the CAC by 12% and resin by 17%, the financial benefit (46% less) is
greater than the efficiency. Also, the benefits to reuse and to reduce waste material make this research
attractive in the long term to the benefit of the environmental issues.