Effect of the activation method on the properties and adsorption behavior of bagasse fly ash-based activated carbon

Bagasse fly ash (BFA) has been intensively studied for activated carbon preparation. Several activation methods have been investigated, i.e., physical activation using steam and CO2, chemical activation using KOH, and one step combination method between chemical and CO2 physical activation (physiochemical activation). Using coarse BFA particles as the precursor, it was observed that steam activation mainly enhances mesopores, while CO2 and KOH activation develops particularly the micropores inside the carbon matrix. A typical activation using KOH as the chemical agent at 700 °C improved initial porosity up to 2571 m2/g of BET surface area and 1.324 cc/g of total pore volume. The effect of the activation method on the surface chemistry of the activated carbons was also studied. To measure the adsorption performance, liquid phase phenol adsorption experiments were conducted. The highest Langmuir monolayer adsorption capacity of 3.22 mmol/g was achieved by a KOH activated sample.

► Fly ash particle characterization using SEM-EDS atomic mapping. ► Coarse particles's suitability for activated carbon precursors. ► Activation process controlling activated carbon's textural and chemical properties.