II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-4
Not large number of publication regarding the adsorbents prepared from miscanthus grass
became the reason of our investigations on possibility of preparation of sorbents from this raw
material in one step activation process, using water vapour as a gasifying agent.
The properties and structure of active carbons obtained from miscanthus grass were
determined. Moreover, the applicability of these sorbents for purification of aqueous solutions
contaminated with toluene, p-chlorophenol, methylene blue and Congo red was examined.
The raw material (miscanthus grass) was used in the form of briquettes.
One-step carbonization and activation process was performed in the horizontal pipe
rotating reactor introduced in the electrical furnace. Preliminary (carbonization step) the
sample was heated in the nitrogen atmosphere with the heating rate 10 deg/min up to the final
temperatures: 700, 750 and 800 o C. The residence time at these temperatures was 15 min.
Subsequently, the gasifying agent (steam) was introduced and activation step was conducted
at a proper final temperature. The activation time was changed from 15 to 60 min.
During the investigations the following determinations were performed: microstrength,
iodine number, methylene number and technical analysis of the raw material, char and
selected active carbon. Additionally the purification tests for water contaminated by toluene,
p-chlorophenol, methylene blue and Congo red were conducted.
It was stated that miscanthus grasses are the suitable raw material for obtaining of
granular active carbons of high microstrength. The properties and structure of active carbons
prepared from miscanthus grasses change with the temperature and the activation time.
The chars prepared from miscanthus grass exhibit relatively high microstrength. In their
structure the ultramicropores are dominating. This is the reason for low iodine and methylene
numbers observed. The chars were non-effective in water purification tests – only toluene was
removed from the water solution by this chars.
The process of activation of char from miscanthus caused the growth of iodine and
methylene numbers as well as the development of pore system in the range of wider
micropores and mesopores.
The efficiency of decontamination of water solution from toluene, p-chlorophenol,
methylene blue and Congo red by active carbons prepared from miscanthus grass is high and
grows with temperature and activation time.
Toluene was observed to be the most easily removed contaminant using all active carbons
prepared from miscanthus grass biomass. Congo red was the most troublesome contaminant
for purification with examined sorbents.
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