Lignin Microspheres Modified with Magnetite Nanoparticles as a Selenate Highly Porous Adsorbent

Area of Science:

• Environmental Science
• Materials Science
• Water Treatment

Background:

• Selenate (Se(VI)) is a prevalent water contaminant.
• Effective removal of selenate is crucial for environmental and human health.
• Lignin-based materials offer a sustainable platform for water remediation.

Purpose of the Study:

• To develop and evaluate novel lignin-based microspheres for selenate removal.
• To investigate the adsorption mechanism and capacity of the modified adsorbent.
• To assess the adsorbent's performance in real water samples and explore regeneration potential.

Main Methods:

• Synthesis of porous lignin-based microspheres modified with magnetite nanoparticles.
• Batch adsorption experiments to study the effect of initial selenate concentration, adsorbent dosage, and contact time.
• Characterization of the adsorbent using FTIR, XRD, and SEM.
• Testing in real water samples and evaluation of desorption and regeneration.

Main Results:

• Maximum adsorption capacity of 69.9 mg/g for Se(VI) at pH 6.46.
• Effective removal of Se(VI) from real water samples with an average efficacy of 20%.
• Achieved 61% regeneration in one desorption cycle using 0.5 M NaOH.

Conclusions:

• Magnetite-modified lignin microspheres are a promising adsorbent for selenate removal.
• The adsorbent exhibits significant affinity for Se(VI) but limited multi-cycle application.
• The loaded sorbent can be repurposed as a selenium fertilizer.