Efficient degradation of phenanthrene by biochar-supported nano zero-valent iron activated persulfate: performance evaluation and mechanism insights

• Published in: Environmental science and pollution research international 2023-12, Vol.30 (60), p.125731-125740
• Main Authors: Zhou, Lai, Wang, Yichen, Li, Danqiong, Zhang, Jiehui, Zhu, Xueqiang
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Charcoal; Charcoal - chemistry; Degradation; Dosage; Earth and Environmental Science; Ecotoxicology; Electron microscopy; Electron paramagnetic resonance; Electron spin resonance; Environment; Environmental Chemistry; Environmental Health; Fourier transforms; Free radicals; Infrared spectroscopy; Iron; Iron - chemistry; Liquid phases; Microscopy; Performance evaluation; Phenanthrene; Phenanthrenes; Reduction; Research Article; Scanning electron microscopy; Sodium persulfate; Transmission electron microscopy; Waste Water Technology; Water Management; Water Pollutants, Chemical - analysis; Water Pollution Control
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-023-31002-9

Biochar-supported nano zero-valent iron (BC@nZVI) is a novel and efficient non-homogeneous activator for persulfate (PS). This study aimed to identify the primary pathways, the degradation mechanism and the performance of phenanthrene (PHE) with PS activated by BC@nZVI (BC@nZVI/PS). BC@nZVI as an activator for PS was prepared by liquid phase reduction method. BC@nZVI was characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffractometer and Fourier transform infrared spectroscopy. The effects of the iron-carbon mass ratio and BC@nZVI dosage were investigated, and a pseudo-first-order kinetic model was used to evaluate the PHE degradation. The results showed that BC supported nZVI and inhibited the agglomeration of nZVI, improving PS’s activation efficiency. The optimal iron-carbon mass ratio was determined to be 1:4, accompanied by a dosage of 0.6 g/L of BC@nZVI. During PS activation, nZVI was transformed to Fe 2+ and Fe 3+ , with the majority being Fe 3+ . The reducibility of nZVI in BC@nZVI enabled the reduction of Fe 3+ to Fe 2+ to activate PS. Radical quenching and electron paramagnetic resonance (EPR) revealed that the oxidative radicals in the BC@nZVI/PS system were mainly SO 4 - · and ·OH, where SO 4 - · was the primary free radical under acidic and neutral conditions and ·OH in alkaline conditions. Additionally, BC@nZVI adsorption had a limited role in PHE removal. This study can provide mechanism insights of PHE degradation in water with BC@nZVI activation of the Na 2 S 2 O 8 system. Graphical abstract