Cu-Doped magnetic loofah biochar for tetracycline degradation via peroxymonosulfate activation

Biochar emerged as a promising material due to its high efficiency and tunable physicochemical properties. In order to improve the economic applicability of biochar catalysts, we attempted to apply formed Cu-doped deactivated magnetic loofah biochar (Cu-Fe-LBC) as a peroxymonosulfate (PMS) activator to remove tetracycline (TC). The catalyst exhibited high activation of PMS and high stability with the TC removal of 97.6%. The chemical composition and groups on the catalyst surface confirmed the presence of copper ions on the biochar by complexation with COO–. Analysis of quenching experiments and electron paramagnetic resonance indicated the significance of HO˙ and 1O2 in TC degradation. The catalytic system had high catalytic efficiency with a wide pH range and coexisting anions. The possible degradation mechanism was proposed. Moreover, the research provides an insight into the PMS activation by reusing waste biochar catalysts.