Nanostructured, Biodoping-Activated Fungi-Modified Wood for Enhanced Cd²⁺ Removal: Performances and Insight on...

Nanostructured activated carbon (AC) adsorbents derived from woody biomass have garnered attention for their potential usage to remove toxic substances from the environment due to their high specific surface area, superior micro/mesoporosity, and tunable surface chemistry profile. However, chemical dopants widely used to enhance the chemical reactivity with heavy metals would pollute the environment and conflict with the vision of a cleaner and sustainable environment. Herein, we report a facile, green, and sustainable approach using fungi modification combined with alkali activation to produce AC for heavy metal removal. The decayed wood-derived AC (DAC) exhibited a high specific surface area of 2098 m²/g, and the content of O and N functional groups was 18 and 2.24%, respectively. It showed remarkable adsorption capacity toward Cd²⁺ of 148.7 mg/g, which was much higher than most reported Cd²⁺ adsorbents. Such excellent adsorption capacity was primarily based on enhanced physical adsorption (pore filling, π-π) and chemical adsorption (functional group complexation, ion exchange, and precipitation). Additionally, the DAC showed rapid kinetics and remarkable applicability in both dynamic environments and actual water samples. These results suggest that decayed wood has excellent potential for efficient use in the removal of Cd²⁺ from wastewater. Furthermore, these results indicate that decayed wood can be cleanly produced into high efficiency heavy metal adsorbents to realize value-added utilization of decayed wood.