Novel Mesoporous Lignin-Calcium for Efficiently Scavenging Cationic Dyes from Dyestuff Effluent

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Industrial wastewater often contains toxic cationic dyes like methylene blue (MB).
• Effective and sustainable methods are needed for dye removal from effluents.
• Lignin, a byproduct of the paper industry, offers potential as a low-cost adsorbent material.

Purpose of the Study:

• To fabricate and characterize a novel lignin-calcium adsorbent for methylene blue removal.
• To investigate the adsorption mechanism, kinetics, and capacity of the lignin-calcium material.
• To evaluate the adsorbent's performance across a range of pH conditions and its regeneration efficiency.

Main Methods:

• Fabrication of lignin-calcium adsorbent using a flocculation-sedimentation method.
• Characterization of the adsorbent's structure and morphology using various analytical techniques.
• Adsorption experiments to determine methylene blue uptake, kinetics, and the influence of pH, analyzed using Langmuir and pseudo-second-order models.

Main Results:

• Lignin-calcium microspheres exhibited a mesoporous, inserted layer structure with a coarse surface.
• Maximum adsorption capacity reached 803.9 mg/g, significantly outperforming existing adsorbents.
• Adsorption followed Langmuir and pseudo-second-order models, indicating chemisorption and pore diffusion mechanisms.
• Effective adsorption was observed across a wide pH range (3-11), with 62.44% elution efficiency using hydrochloric acid for regeneration.

Conclusions:

• The developed lignin-calcium adsorbent is highly effective and sustainable for removing methylene blue.
• Its superior adsorption capacity and recyclability make it a promising candidate for treating dye-containing wastewater.
• This study highlights the potential of utilizing industrial byproducts for environmental remediation applications.