Chitosan-coated sand and its application in a fixed-bed column to remove dyes in simple, binary, and real systems

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Food dyes like tartrazine pose environmental challenges.
• Wastewater treatment requires efficient and cost-effective dye removal methods.
• Chitosan-modified materials offer promising adsorption properties.

Purpose of the Study:

• To investigate the fixed-bed column adsorption of tartrazine yellow food dye.
• To evaluate the performance of chitosan-coated sand in single, binary, and real effluent systems.
• To determine the adsorption capacity and breakthrough time under varying conditions.

Main Methods:

• Fixed-bed column adsorption experiments were conducted using chitosan-coated sand.
• Adsorption was tested in single-dye, binary-dye (tartrazine and sunset yellow), and real industrial effluent systems.
• Flow rates of 3 mL/min and 5 mL/min were evaluated.
• Thomas and Yoon-Nelson dynamic models were applied to analyze breakthrough curves.

Main Results:

• The optimal flow rate for tartrazine adsorption was 3 mL/min.
• In single and binary systems at 3 mL/min, breakthrough times were 95 min and 65 min, with capacities of 595 mg/g and 497 mg/g, respectively.
• In real effluent, breakthrough time decreased to 10 min, and capacity reduced to 191 mg/g for tartrazine.
• Both Thomas and Yoon-Nelson models adequately represented the experimental breakthrough curves.

Conclusions:

• Chitosan-coated sand is an effective adsorbent for tartrazine yellow food dye in fixed-bed systems.
• Adsorption efficiency is influenced by the presence of other dyes and matrix components in real effluents.
• The study validates the applicability of dynamic adsorption models for process design.