Optimization of High Cation Exchange Capacity Modified Coal Fly Ash Using Response Surface Methodology

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ปธานิน แสงอรุณ
ธเรศ ศรีสถิตย์
พงษ์เสริฐ ศรีพรหม


The optimization of high Cation Exchange Capacity (CEC) of the modified coal fly ash was studied. CEC of the coal fly ash before modification was 61.28 meq/100 g. The experimental condition was designed by Box- Benkhen design. The independent variables are retention time (12-36 hr), NaOH concentration (2-4 M) and temperature (80-100 Cº). The result showed that the independent variables had no significant effect to CEC at 95% confidence level (P>0.05). However, The interaction effect between retention time with temperature and NaOH concentration with temperature have significant effect to CEC at 95% confidence  level (P<0.05) Thus, the optimum condition of high CEC (272.12 meq/100 g) was 34 hr of retention time, 4M of NaOH concentration and 80 Cº of temperature. The optimum condition was validated by experimental with 3 times. The results found that CEC of the validated optimum was 269.50±2 meq/100 g which was closely the predicted value.

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