Abstract:
The main objective of this work was to utilize coffee ground waste as the precursor
for activated carbon production using chemical activation with zinc chloride (ZnCl2, widely
used) and potassium carbonate (K2CO3, with less pollution). The effects of preparing
parameters, namely the weight ratio of coffee ground waste to activating agent (WR),
activation temperature and activation time, on iodine number, were studied in order to seek
an optimum activation condition for producing activated carbon. The resulting activated
carbons were classified by iodine number requirement of TISI (Thailand Industrial Standard
Institute). In addition, all data were statistically analyzed by ANOVA and LSD at 95%
confidence interval.
Based on the results of the experiment, it was concluded that coffee ground waste can
be utilized as an alternative precursor for activated carbon production. The optimum
condition of activation using ZnCl2 was 1:3 of WR at a temperature of 800ºC with a retention
time of 3 h, giving a yield of 44.8 % with an iodine number of 901 mg/g and SBET of 1,088
m2/g. In the case of K2CO3, the optimum activation condition was 1:2 of WR at a temperature
of 800ºC with a retention time of 2 h, giving a yield of 18.4 % with an iodine number of 1,190
mg/g and SBET of 943 m2/g. In addition, these results show that the optimum WR and
activation time for K2CO3 is lower than that of ZnCl2, indicating less cost and energy
consumption, and, it is a benign chemical. Therefore, it is reasonable to assume that K2CO3 is
considerably better as an activating agent alternative.