Effect of impregnation ratio and activation temperature on the yield and adsorption performance of mangrove based activated carbon for methylene blue removal
Ridzuan Zakaria, Nur Azimah Jamalluddin, Mohamad Zailani Abu Bakar
Abstract
Mangrove pile leftovers which were found as waste at the construction sites were used as a precursor to prepare activated carbon by adopting phosphoric acid (H₃PO₄) as an activating agent. The effects of H₃PO₄ impregnation ratios (3, 4 and 5) and activation temperatures (300, 400 and 500 °C) on the yield, surface area and the adsorption behavior of the prepared activated carbon were investigated. The highest yield of 45% was obtained for the activated carbon prepared at an impregnation ratio of 3 and at an activation temperature of 300 °C (AC3003). Activated carbon prepared at an impregnation ratio of 4 and an activation temperature of 300 °C (AC3004) gave the highest adsorption capacity of 72.3 mg/g at an initial concentration of 150 mg/L. It could be attributed to the high BET surface area of the prepared AC3004 activated carbon which was 1011.8 m2/g. The combined effect of impregnation ratio of 4 and activation temperature of 300 °C managed to produce a mangrove based activated carbon with a high carbon content (94.18%) and successfully form well-developed pore structures. Experimental data of methylene blue (MB) dye adsorption for AC3004 activated carbon was found to fit well to Langmuir isotherm with a correlation coefficient (R2) of 0.9985, to indicate that the adsorption of MB dye on the activated carbon was a monolayer adsorption. The results of the yield and adsorption study showed that the chemical activation method using H₃PO₄ as an activating agent was suitable for developing mangrove pile based activated carbon prepared for the removal of MB dye in an aqueous solution.