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

Area of Science:

• Environmental Chemistry
• Adsorption Science

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants.
• Natural sorbents like pine bark show potential for PAH removal.
• Sorption efficiency is influenced by sorbent composition and PAH properties.

Purpose of the Study:

• To investigate the sorption of phenanthrene and pyrene onto raw and modified pine bark.
• To understand the role of pine bark components in PAH sorption.
• To evaluate the impact of modification methods on sorption efficiency.

Main Methods:

• Pine bark modification via Soxhlet extraction, saponification, and acid hydrolysis.
• Single-solute and bi-solute sorption experiments with phenanthrene and pyrene.
• Analysis of sorption isotherms and identification of key sorbent components (lignin, polysaccharide).

Main Results:

• Raw pine bark showed high PAH affinity, dominated by partitioning.
• Modified bark exhibited nonlinear sorption due to specific sorbate-sorbent interactions.
• Lignin was identified as a potent sorption medium, but its efficacy was reduced by polysaccharides.
• Acid hydrolysis, by removing polysaccharides, increased sorption capacity by 4-17 folds.

Conclusions:

• Pine bark is a promising natural sorbent for PAH removal.
• Acid hydrolysis significantly enhances pine bark's PAH sorption capacity.
• Optimizing pine bark composition can improve its environmental application for PAH remediation.