CO2 Capture and Ca2+ Exchange Using Zeolite A and 13X Prepared from Power Plant Fly Ash

Zeolite A and 13X were prepared by a hydrothermal treatment using fly ash after alkali fusion. The alkali-fusion condition was optimized to a 1:1.2 fly ash/NaOH weight ratio at 500 degrees C for 1 h, and highly crystalline zeolite A and 13X were obtained at 100 degrees C for 4 h and 90 degrees C for 12 h, respectively. Both products exhibited high Ca2+ ion-exchange capacity (184 and 134 mg/g) and stable CO2 capture cyclic performance (145 and 220 mg/g).