Addressing Europe’s new hunger for sustainable activated carbon in wastewater treatment: Micropollutant removal with residual wood-based adsorbents using different activation strategies
Delphine Bosch, Jan O. Back, Martin Spruck, Luca Nohel, D. Gurtner, Christian Margreiter, Angela Hofmann, Anke Bockreis
Abstract
To meet the recast EU Urban Wastewater Treatment Directive, the EU and Austria will require approx. 270 and 10 kt a −1 of activated carbon, respectively. This study explores the potential of using non-fossil activated carbon derived from residual woody biomass to fulfil this demand using experimental adsorption data. We compared a commercial activated carbon (COM-AC) with three activated carbons produced from local residual wood (ZINC-AC, G-AC, CO2-AC) using various activation strategies. ZINC-AC was produced through one-step chemical impregnation with ZnCl 2 of waste wood. G-AC was a by-product of gasifying forestry residue biomass, and CO2-AC is the CO 2 -activated version of G-AC. Adsorption experiments were performed with a mix of six micropollutants in different water matrices. ZINC-AC exhibited the highest surface area (S BET 1946 m 2 g −1 ) and the second highest micropollutant capacity in tap water (257.4 mg g −1 ), after COM-AC (297.6 mg g −1 ). ZINC-AC's capacity remained stable in wastewater. G-AC showed a low capacity (34.6 mg g −1 ), which could be increased to 105.1 mg g −1 by CO 2 -activation. The predominant removal mechanisms are identified as hydrophobic and π-interactions. The study suggests that these activated carbons from residual woods could be a viable alternative for wastewater treatment, though production yield (35 % vs. 3.5 % for the most promising methods) and quality will be crucial for assessing Europe’s activated carbon production potential from woody biomasses. • Three ACs from residual woody biomass: waste wood and forestry residue biomass. • High S BET of AC (1942 m 2 g −1 ) by chemical activation of waste wood. • Accumulated micropollutant adsorption capacity of up to 257.4 mg g −1 . • Forecast EU-wide AC demand of 270 kt a −1 – EU supply potential controlled by yield.