The production and characterization of activated carbon using local agricultural waste through chemical activation process
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Date
2007
Authors
Nurul’ain, Jabit
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Abstract
Activated carbon from coconut shell and palm kernel shell has been successfully
produced through chemical activation process using zinc chloride and phosphoric acid as
activating agents. The effect of activation temperature, activation time and concentration
of activating agent on BET surface area, surface morphology and yield (dry weight basis)
were studied. The result showed that in all cases, increasing the activation temperature
from 300°C to 500 °C and activation time from 60 to 180 minutes caused a decrease in the
percentage yield while the BET surface area is increased, progressively. The highest BET
surface area of the activated carbon obtained by using 5 M zinc chloride concentration and
30% concentration of phosphoric acid is 893 m2/g and 833 m2/g respectively. Hence, the
optimum temperature for production of activated carbon was obtained at 500°C and
optimum activation time was obtained at 120 minutes. Characterization of the activated
carbon produced was done by selecting four samples from both the raw materials (CS &
PS) at optimum temperature, activation time and concentration (CSZ, PSZ, CSH, PSH).
Elemantal analysis showed that carbon content in the samples is high which is over 75%
and the nitrogen and sulphur content is less than 0.1%. While, the fixed carbon of
activated carbon produced is in the range of 54% to 79% and the volatile matter left is from
11% to 36%. The moisture content is less than 10% and finally ash content is less than
2% for all samples selected. FTIR analysis showed the hydroxyl, carbonyl, aliphatic,
ethers, alcohol, phenol and carboxylic groups are present on the surfaces of both the raw materials. After the activation and carbonization process, the new functional groups were assigned
such as carbon-aromatic groups and polyphosphate esters on activated carbon produced
and some of the functional groups were eliminated such as carboxylic, alcohol and
carbonyl. The adsorption capacity test of the produced activated carbon was determined
by iodine number. The highest iodine number obtained from CSZ and PSH samples are
966 and 959 mg/g respectively. The cyanide removal efficiency was carried out to
determine the potential application of produced activated carbon. The percentage of
cyanide removal is successfully obtained more than 98 % at initial cyanide concentration
of 25 mg/l by using 0.5g of activated carbon produced from palm kernel shell through
phosphoric acid activation (PSH) impregnated with 5 % of copper from Cu(II)SO4 solution.
For raw activated carbon (non-impregnated AC), the results showed a lower cyanide
removal of below 60 % at initial cyanide concentration of 25 mg/l and 50 mg/l. From the
cyanide removal test, the activated carbon produced from coconut shell and palm kernel
shell by chemical activation can be used as an adsorbent in cyanide waste water
treatment.
Description
Master
Keywords
Materials and Mineral Resources Engineering , Activated carbon , Local agricultural waste , Chemical activation process