Photo-transformation of biochar-derived dissolved organic matter and its binding with phenanthrene/9-phenanthrol: The role of functional group and pyrolysis temperature

• Published in: Bioresource technology Vol. 413; p. 131547
• Main Authors: Niu, Yifan, Wang, Siyao, Gao, Peng, Ren, Xin, Li, Fangfang, Liu, Zhanpeng, Wang, Lin, Peng, Hongbo, Ju, Shaohua
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2024
• Subjects: Binding mechanism; Biochar-derived dissolved organic matter; Fluorescence quenching; Photo-transformation; Polycyclic aromatic hydrocarbon; Biochar-derived dissolved organic matter; Binding mechanism; Polycyclic aromatic hydrocarbon; Photo-transformation; Fluorescence quenching
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131547

[Display omitted] •After 20 h of irradiation, 11.3 % BDOM mineralized, forming CH3/CH2/CH aliphatics.•BDOM400 exhibited 44% and 52% max binding with PHE and PTR, strong affinity.•Max binding of BDOM and PHE rose 12 % after 20 h light exposure.•The main quenching mechanisms for PHE and PTR were static and dynamic quenching. This study explores the physicochemical attributes of dissolved organic matter from rice straw biochar (BDOM) at varying pyrolysis temperatures and photo-irradiation conditions, focusing on the binding mechanisms of phenanthrene (PHE) and 9-phenanthrol (PTR) using multiple spectroscopic techniques and fluorescence quenching. Following 20 h of photo-irradiation, only 11.3 % of BDOM underwent mineralization, forming new CH3/CH2/CH aliphatics structures. BDOM from biochar produced by pyrolysis at 400°C exhibited a stronger binding affinity with PHE and PTR, achieving 44 % and 52 % maximum binding, respectively. Static and dynamic quenching governed PHE and PTR binding, which was influenced by temperature. Photo-irradiated BDOM showed enhanced binding with PHE, attributed to increased aliphatic content. Hydrogen bond and π-π electron-donor–acceptor (EDA) interactions dominated PTR binding, while π-π interactions and hydrophobic interactions controlled PHE. This study provides valuable insights into BDOM photochemical behaviors and their impact on the environmental fate of polycyclic aromatic hydrocarbons (PAHs) after BDOM photo-irradiation.