Interaction between biochar-dissolved organic matter and chlorophenols during biochar adsorption

Area of Science:

• Environmental Chemistry
• Soil Science
• Bioremediation

Background:

• Biochar (BC) is used for chlorophenol (CP) remediation, but the role of its dissolved organic matter (BDOM) is poorly understood.
• Investigating BDOM interactions with CPs is crucial for optimizing BC-based remediation strategies.
• Peanut hull (PDOM) and corn stalk (CDOM) derived DOM were used to study interactions with 2,4,6-trichlorophenol (TCP).

Purpose of the Study:

• To elucidate the role and mechanisms of BDOM in the remediation of CPs.
• To analyze the interactions between PDOM/CDOM and TCP using spectroscopic and modeling techniques.
• To determine the binding affinity and quenching mechanisms between BDOM components and TCP.

Main Methods:

• Excitation-emission matrix (EEM) spectroscopy combined with fluorescence region integration (EEM-FRI) and parallel factor analysis (EEM-PARAFAC).
• Analysis of humic-like, protein-like, and fulvic-like materials within PDOM and CDOM.
• Application of the modified Stern-Volmer model to calculate stability constants (Log KTCP) and identify quenching mechanisms.

Main Results:

• Humic-like materials constituted over 60% of both PDOM and CDOM; CDOM had higher protein- and fulvic-like content.
• Protein- and fulvic-like components were the primary interactors with TCP, showing over 25% fluorescence decrease.
• Static quenching was the dominant mechanism, with stability constants (Log KTCP) ranging from 3.53 to 4.73 for PDOM and CDOM.

Conclusions:

• BDOM plays a significant role in CP remediation, with protein- and fulvic-like fractions being key.
• The sequential binding order of TCP to fluorescent components in BDOM was identified.
• Findings support biochar screening for CP remediation and understanding environmental DOM behavior during BC application.