Effects of chemical activating agents on physical properties of activated carbons - a commentary

Well-developed surface areas and porous structures that render high adsorption capacity are necessary for pollutant removal from wastewater by activated carbons. Activated carbons from natural resources, and agricultural and industrial waste materials are produced using chemical agents, including KOH, H3PO4, K2CO3, ZnCl2 and NaOH. This study is intended to highlight the effects of those agents on the physical properties of the activated carbons. The operating conditions, i.e., temperature, time and ratio, show an interplay towards the physical properties at varying degree. The yield, pore size, mesoporosity and surface area of activated carbons derived using different chemical agents correlate well with the impregnation ratio. Generally, the pore size, mesoporosity and surface area increase, while the yield decreases with increasing ratio (over a given range). Higher ratio and temperature are recommended for KOH, K2CO3 and NaOH activation, to endow activated carbons with greater surface area.