Abstract: “This work focus on the synthesis of a NaA zeolite from oil palm ash and coal bottom ash and the CEC assessment of synthesized products. Zeolite synthesis was carried out at three alkaline salts (NaOH, KOH, Ca(OH)2) and three time levels (1, 3 and 5 hours)at the temperature of 105 oC and two concentration of base concentration (1 and 3 M). Consequently, Zeolite NaA was produced from coal bottom ash with a good calcium exchange capacity (CEC) was used as sulfate, hardness, ammonia and phosphate adsorbent. The coal bottom ash and aluminium hydroxide sludge were sources of starting materials for Na-A zeolite (4A zeolite) conversion using the fusion prior alkali hydrothermal process. The coal bottom ash and NaOH were mixed at the weight ratio of 1:1.2 and 1:1:3 and then fused at 700 oC for 1 hour prior to the hydrothermal treatment. Sodium hydroxide solution of 3 M was added to the fused material and thoroughly stirred at 105± 3 oC in the stainless steel reactor. The reaction time was vari”

Keywords: Na-A zeolite, Wastewater treatment, sulfate, hardness, Coal Bottom Ash, Aluminium Hydroxide Sludge, Fusion Method, Waste Utilization