Formation of persistent free radicals in sludge biochar by hydrothermal carbonization - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Environmental Chemistry Letters Année : 2021

Formation of persistent free radicals in sludge biochar by hydrothermal carbonization

Résumé

The uses of biochar as soil fertilizer can offset global warming and reduce dependence on limited mineral resources in the future circular economy, yet biochar may contain contaminants that can ultimately enter the food chain. In particular, persistent free radicals are emerging contaminants previously detected in biochar but underlying mechanisms of radical formation are not yet established. Here we studied radical generation during hydrothermal carbonization of waste sludge at 160-220 ºC for 0.5-2 h with solid weight ratios of 10%w-40%w using electron paramagnetic resonance and Fourier transform infrared spectrometry. Results reveal that radical concentration increases with temperature, reaction time, and weight ratio in sludge biochars, reaching a content of 47.2 × 10 15 spins/g for 220 ºC, 2 h heating, and 40%w solid ratio. Moreover, low temperature of about 160 ºC favors the production of oxygen-centered radicals, whereas higher temperature of 220 ºC produces carbon-centered radicals. Our findings imply that biochar ecotoxicity should be assessed prior applications to prevent adverse health effects.
Fichier principal
Vignette du fichier
Tang-Formation2021revised.pdf (1.05 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03260080 , version 1 (14-06-2021)

Identifiants

Citer

Zheng Tang, Song Zhao, Yajie Qian, Hanzhong Jia, Pin Gao, et al.. Formation of persistent free radicals in sludge biochar by hydrothermal carbonization. Environmental Chemistry Letters, 2021, 19 (3), pp.2705 - 2712. ⟨10.1007/s10311-021-01198-8⟩. ⟨hal-03260080⟩
56 Consultations
199 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More