Boron Adsorption on Palm Oil Mill Boiler (POMB) Ash Impregnated with Chemical Compounds

Boron removal from synthetic wastewater by using palm oil mill boiler (POMB) ash impregnated with various chemical compounds (citric acid, tartaric acid, salicylic acid, barium chloride, calcium chloride anhydrous, and calcium chloride dihydrate) was being investigated in this study. The characteristics of POMB ash were analyzed based on ash content, carbon content, and BET surface area. The adsorption process was performed in a batch system with various parameters: dosage of POMB ash, residence time, shaking speed, temperature, and pH. The results show that impregnants increased the ability of POMB ash to adsorb boron, and the adsorption efficiency of boron was highly dependent on the pH. The optimization study shows that citric acid was the optimum impregnant on the POMB ash, with maximum boron removal efficiency of 65.69% at dosage of 6 g/50 mL at pH 7.0 with shaking speed of 100 rpm at 25 °C and 12 h of residence time.