Bio-based activated carbon from husk- and wood-based biomass: comparison of carbon activation methods on organic pollutants removal

Abstract

This study aimed to investigate the effect of different activations on the properties of bio-based activated carbons (BACs) for water treatment. BACs were produced via pyrolysis by the carbonization stage and were followed by four different activation procedures. Chemical activation included the introduction of metal oxides or alkali on the structure of the sawdust-derived BACs, resulting in iron-activated carbon (BAC-Fe), copper-activated carbon (BAC-Cu), and sodium-activated carbon (BAC-Na). The physical activation was conducted in a CO2 environment with the usage of two types of locally available biomasses, resulting in husk-activated carbon (HAC) and wood-activated carbon (WAC). Depending on the activation, BACs can be developed with high porosity, active sites, and different additional functionalities such as antimicrobial and magnetic. The adsorption of natural organic matter (NOM) with chemically activated BACs yielded high removal percentages (97, 87, and 80% for BAC-Fe, BAC-Cu, and BAC-Na, respectively). The physically activated BACs demonstrated high adsorption capacities for dye – 278 mg/g for WAC and 213 mg/g for HAC. This outlines a wide range of BAC production possibilities with advanced functionalities. HIGHLIGHTS Various production parameters and methods allow the modification of final properties of bio-based activated carbons.; Physical activation provides sufficient surface area for pollutants such as dye; it is cheap and environmental friendly.; Chemical activation allows the implementation of functional groups on carbon surfaces to improve adsorbent selectivity and reach specific properties.;

Keywords

• activation
• adsorption
• bio-based activated carbon
• dye
• natural organic matter
• water treatment