One-step synthesis of nanoscale zero-valent iron modified hydrophobic mesoporous activated carbon for efficient removal of bulky organic pollutants

It is of vital importance for industrial applications by developing simple, robust, economic, eco-friendly and easy scale-up methods for fabricating hydrophobic mesoporous activated carbon (MAC) from sustainable raw materials with high adsorption performance for bulky organic pollutants removal. Herein, a novel one-step facile approach coupling carbothermal reduction with catalytic activation was firstly established for preparing the coconut shell-based hydrophobic MAC modified with nanoscale zero-valent iron ([email protected]). The in-situ synthesized NZVI (merely 0.33 wt%) by carbothermal reduction could not only catalyze the gasification reaction between carbon and CO2 to fabricate MAC (dBET = 5.17 nm, SBET = 933.12 m2 g−1), but also catalyze the amorphous carbon to form hydrophobic graphitic layers covering its surface. In striking contrast to the unmodified activated carbon, the [email protected] surprisingly exhibited a remarkably 8.62-fold higher initial adsorption rate and a slightly increased adsorption capacity of 327.60 mg g−1 for bisphenol A (BPA). Intriguingly, the high mesoporous proportion (70–90%) of [email protected] with the average pore size of 4.1–5.2 nm was effective in reducing the diffusion resistance for BPA. Such high adsorption performance under neutral conditions was primarily attributed to the strong hydrophobic interaction, π-π interaction and the weak hydrogen bonding. Moreover, the [email protected] showed robust anti-interference properties in actual environmental conditions containing various inorganic ions and in a wide pH range (3–10). Therefore, the cost-effective, eco-friendly, sustainable and recyclable hydrophobic [email protected] with stable structure and excellent performance for bulky organic adsorption is a promising material for practical applications, especially in drinking water purification.