Impact of carbonization conditions and adsorbate nature on the performance of activated carbon in water treatment

Abstract

The physical and chemical structure of activated carbon (AC) varies with the carbonization temperature, activation process and time. The texture and toughness of the starting raw material also determine the morphology of AC produced. The Brunauer-Emmet-Teller surface area (SBET) is small for AC produced at low temperatures but increases from 500 to 700 °C, and generally drops in activated carbons synthesized > 700 °C. Mild chemical activators and low activator concentrations tend to generate AC with high SBET compared to strong and concentrated oxidizing chemicals, acids and bases. Activated carbon from soft starting materials such as cereals and mushrooms have larger SBET approximately twice that of tough materials such as stem berks, shells and bones. The residual functional groups observed in AC vary widely with the starting material and tend to reduce under extreme carbonization temperatures and the use of highly concentrated chemical activators. Further, the adsorption capacity of AC shows dependency on the size of the adsorbate where large organic molecules such as methylene blue are highly adsorbed compared to relatively small adsorbates such as phenol and metal ions. Adsorption also varies with adsorbate concentration, temperature and other matrix parameters.

Research on the Migration and Adsorption Mechanism Applied to Microplastics in Porous Media: A Review

“…Wood, as a natural biomass, exhibits a multi-scale porous structure ranging from macro to nano levels [ 60 ], and the adsorption capacity of wood can be significantly improved by making activated carbon from wood through high-temperature carbonization treatment for use in column experiments. This is due to the fact that its porous structure and surface functional groups contribute to the adsorption efficiency [ 61 ]. Zeolites have a high specific surface area and abundant pore structure [ 62 ], enabling them to adsorb a large number of molecules and improve separation efficiency.…”