Iron nanoparticles in situ encapsulated in lignin-derived hydrochar as an effective catalyst for phenol removal

In this work, we have developed a low-cost and green strategy for nanoscale zero-valent iron (ZVI) in situ encapsulated in lignin-derived hydrochar (Fe@HC) by a facile one-pot synthesis route. The as-synthesized Fe@HC was characterized for physicochemical properties by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscope (TEM), thermal gravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FT-IR). Further catalytic experiment revealed that phenol could be completely degraded by Fe@HC-800 within 20 min with peroxymonosulfate (PMS) at mild temperatures. Fe@HC-800 catalyst also exhibited stable performance after three runs of regeneration. The XPS and XRD results proved the key role of Fe-0 in the degradation of phenol. This approach is of great potential to the development of green materials biomass-derived carbon materials for wastewater treatment applications.