Highly Graphitic and Weak-Polar Fe-Carbon with Self-Stacked Nanospongy Structure Derived from Silkworm Excrement for Enhanced Selective Recognition of Flavor Anisole

A unique nano-spongy porous Fe-C derived from self-assembly insect-made biomass source (silkworm excrement, SE) was prepared for selective separation of flavor 4-methylanisole (4-MA) from its binary mixture anisaldehyde (AY). We used FeCl₂/ZnCl₂ to catalyze SE to a special porous Fe-C (NSCF) by a facile “one-pot” calcination strategy. NSCF exhibited a unique nano-spongy morphology anchoring Fe₃C/Fe₅C₂ in nano-sheeted carbon, which showed an enriched graphitic surface with high dispersion of weak-polar Fe sites. Selective adsorption experiments and DFT simulations demonstrated that 4-MA possessed high electron density in benzene ring and relatively weak polar alkoxy (-COCH₃) group, which intensified π-π interaction and weak-to-weak polar attraction with NSCF. This multipiont adsorption made NSCF exhibit an outstanding adsorption capacity (7.3 mmol/g) and selectivity (43.7) at 298 K. This low-cost and eco-friendly carbon from agro-industrial waste can be envisaged as promising adsorbent for highly selective separation of flavoring molecules from hardly separating mixture systems.