Lead removal by a magnetic biochar derived from persulfate-ZVI treated sludge together with one-pot pyrolysis.

In this study, a novel method to treat the persulfate-ZVI dewatered WAS by producing a magnetic biochar as an environmentally friendly biosorbent (nZVI-WSBC) to remove heavy metals (HMs) from wastewaters was proposed. The nZVI-WSBC exhibited good adsorption property of Pb2+ and the adsorption isotherm data were fitted well to Langmuir isotherm. Corresponding reaction kinetics fitted well with the pseudo second-order adsorption model. Notably, nZVI-WSBC was successfully used for efficient removal of HMs from real. This study comprehensively demonstrates the mechanisms between Pb2+ and nZVI-WSBC surfaces, providing a breakthrough in making a sustainable biosorbent from the dewatered iron-containing WAS.

Rapid decolorization of dye Orange G by microwave enhanced Fenton-like reaction with delafossite-type CuFeO2.

Bimetallic oxide CuFeO2 as a new heterogeneous catalyst has shown much higher catalytic ability for activating peroxide than single-metal oxides. The present work demonstrated a synergistic microwave (MW) enhanced Fenton-like process with CuFeO2 for rapid decolorization of azo dye Orange G (OG). The MW irradiation dramatically enhanced the OG degradation efficiency, achieving 99.9% decolorization within 15min at pH5. The XRD analysis of reused CuFeO2, together with metal leaching tests, indicated merits of recycling for CuFeO2. The subsequent surface element analysis by XPS for fresh and used CuFeO2 showed a complex network for reactions between copper-iron redox pairs and surface hydroxyl groups, leading to a synergistic Fenton-like system accelerated by MW irradiation. In the CuFeO2 initiated Fenton-like reactions, several oxidant species (i.e., OH, O2-, electron hole, and FeIVO) responsible to the OG oxidation were identified by quenching experiments, showing the MW generated high temperature and "hot spots" enhanced the yield of OH by generation of electron-hole pairs. Further, the 26 detected degradation products confirmed the OH dominant oxidation of OG. This study shows that the MW-enhanced Fenton-like reaction using CuFeO2 has potential applications for rapid decolorization of dye effluent.