Enhanced sorption of polycyclic aromatic hydrocarbons from aqueous solution by modified pine bark

Area of Science:

• Environmental Chemistry
• Materials Science
• Bioremediation

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants requiring efficient removal methods.
• Natural sorbents like pine bark offer potential for PAH remediation but require optimization.
• Understanding sorption mechanisms is crucial for developing effective PAH removal strategies.

Purpose of the Study:

• To investigate the sorption efficiency of raw and modified pine bark for phenanthrene and pyrene.
• To identify the role of different pine bark components (lignin, polysaccharide) in PAH sorption.
• To evaluate the impact of acid hydrolysis on enhancing pine bark's PAH removal capabilities.

Main Methods:

• Pine bark modification via Soxhlet extraction, saponification, and acid hydrolysis to create distinct fractions.
• Single-solute and bi-solute sorption experiments using phenanthrene and pyrene.
• Analysis of sorption isotherms and identification of dominant sorption mechanisms (partitioning, specific interactions).

Main Results:

• Raw pine bark demonstrated high affinity for PAHs, primarily through partitioning.
• Modified bark exhibited nonlinear sorption isotherms due to sorbate-sorbent aromatic core interactions.
• Acid hydrolysis significantly increased PAH sorption (4-17 fold) by removing suppressive polysaccharides, with lignin identified as a key sorption medium.

Conclusions:

• Pine bark possesses significant potential for PAH removal.
• Acid hydrolysis is a highly effective pretreatment for enhancing pine bark's sorption capacity.
• Optimized pine bark sorbents show promise for practical environmental applications in PAH remediation.