Activated biochar derived from Enteromorpha with high specific surface area for efficient removal of phenanthrene:...

Conversion of solid marine waste into innovative nanomaterials has been successfully developed for removing organic pollutants from aqueous solutions. In this study, activated biochar (HTST) was successfully synthesized using a straightforward three-step method involving pretreatment, carbonization, and chemical regulation. Multiple characterization techniques revealed the presence of abundant three-dimensional hierarchical porous structures in the samples, along with amorphous and active functional group structures such as -COOH, -OH, -NHR, -CC, and C-O. Notably, the prepared sample exhibited a remarkable specific surface area (S_BET) of 3284.52 m²/g, which was close to 1700 times larger than that of the raw biomass. Additionally, the highest removal efficiency could reach approximately 100% under neutral condition, while the adsorption capacity even achieved up to 782.37 mg/g within 2 h at room temperature. Calculations simulation not only highlighted the significance of the π-π conjugation between sample and pollutant molecules, but deeply explored the bonding interaction of active functional groups on the surface, whereas adsorption energies of different configurations had the following order: ΔE(-NHR) = 0.75194674 eV > ΔE(-OH) = 0.72502369 > ΔE(-COOH) = 0.71488135 > ΔE(-CC-) = 0.53852269 eV. Moreover, the adsorption activities for the optimized configuration were further analyzed based on the LUMO-HOMO energy gap and electric distribution. This work presents a viable synthesis method for low-cost nanomaterials and offers new insights into the exceptional adsorption properties of advanced adsorbents for wastewater treatment.