One-step synthesis of biocarbon based nano zero-valent iron for efficient Rhodamine B removal in Fenton-like reactions

Organic pollutants in wastewater became a major challenge in the field of environmental remediation. In this work, biochar-loaded nano zero-valent iron (BC@nZVI) was successfully prepared and used to activate persulfate (PS) for Rhodamine B (RhB) removal from water. The structure and morphology of the nanocomposites were characterized by scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller testing, and Raman spectroscopy. The effects of pyrolysis temperature and iron loading on RhB removal were investigated, and the optimum conditions of RhB removal were determined by reaction parameters: BC@nZVI dosage, PS concentration, pH values, reaction temperature, and inorganic anions in the BC@nZVI/PS system. Acidic and high-temperature conditions were more favorable for RhB removal. Additionally, free radical burst tests and electron paramagnetic resonance assays showed that SO4 center dot - and center dot OH were generated and worked in the removal process, while SO4 center dot- is the main active species. BC@nZVI is an excellent catalyst for the treatment of RhB and provides an eco-friendly strategy for the treatment of organic pollutants in wastewater, with a broad application prospects.