ENIVRONMENT ASIA

Volume 12, No. 02, Month MAY, Year 2019, Pages 58 - 68

Optimization conditions for increasing cation exchange capacity of coal fly ash zeolite modified with chitosan using box-behnken design

Pathanin Sangaroon, Thares Srisatit, and Pongsert Sriprom

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The optimization conditions of high Cation Exchange Capacity (CEC) of coal fly ash (CFA) zeolite modified with chitosan were studied. The experimental design had employed Box-Behnken design with 3 factors at 3 levels. The independent variables were chitosan concentration (5-15 g/L), retention time (12-36 hours), and temperature (40-60ºC). It is resulted that the independent variables of chitosan concentration had significant effect to CEC at 95% confidence (P<0.05). In vice versa, retention time and temperature had no significant effect to CEC at 95% confidence (P>0.05). However, the interaction effect between chitosan concentration with retention time and retention time with temperature had significant effect to CEC at 95% confidence (P<0.05) Thus, the optimum conditions of high CEC (474.21 meq/100g) were 15 g/L of chitosan concentration, 36 hours of retention time, and 40ºC of temperature. Regarding with 3 times of validation for such optimum conditions, CEC was 474.21± 5 meq/100g which was closely the predicted value. CEC of chitosan modified with CFA-zeolite had CEC more than CFA-zeolite (272.12 meq/100g) about 2 times, indicating chitosan was the appropriate material for increasing CEC on CFA-zeolite.

Keywords

Coal fly ash; Cation exchange capacity; Response surface methodology; Box- Behnken Design; Zeolite

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