Selective adsorption of phenanthrene dissolved in Tween 80 solution using activated carbon derived from walnut shells

Area of Science:

• Environmental Chemistry
• Materials Science
• Adsorption Technology

Background:

• Phenanthrene (PHE) is a polycyclic aromatic hydrocarbon pollutant found in surfactant solutions.
• Effective removal and recovery of PHE and surfactants are crucial for environmental remediation and resource management.
• Activated carbon (AC) is a potential adsorbent, but its preparation from waste materials requires further investigation.

Purpose of the Study:

• To prepare and characterize activated carbon (AC) from waste walnut shells for phenanthrene (PHE) removal.
• To investigate the selective adsorption of PHE and the recovery of Tween 80 from aqueous solutions using AC.
• To evaluate the adsorption kinetics, isotherm, thermodynamics, and regeneration efficiency of the prepared AC.

Main Methods:

• Activated carbon preparation from waste walnut shells.
• Characterization of AC using BET, FESEM, FTIR, and XPS techniques.
• Batch adsorption experiments for PHE and Tween 80, followed by kinetic, isotherm, and thermodynamic analyses.

Main Results:

• AC derived from walnut shells exhibited suitable properties for PHE adsorption.
• The adsorption process followed pseudo-second-order kinetics and Langmuir isotherm models.
• Optimal conditions achieved 95% PHE removal and 90% Tween 80 recovery.
• Regenerated AC maintained significant PHE removal efficiency (80% after two cycles).

Conclusions:

• Waste walnut shell-derived AC is an efficient and cost-effective material for selective PHE adsorption and Tween 80 recovery.
• The study demonstrates a sustainable approach for treating contaminated surfactant solutions.
• The regenerated AC offers a viable option for repeated use in environmental cleanup applications.