Chitosan-glutaraldehyde copolymers and their sorption properties

Area of Science:

• Polymer Chemistry
• Materials Science
• Environmental Science

Background:

• Chitosan is a biopolymer with potential applications in pollutant removal.
• Cross-linking is crucial for enhancing chitosan's structural integrity and sorption capabilities.
• Understanding the impact of reaction conditions on copolymer properties is essential for optimizing performance.

Purpose of the Study:

• To synthesize and characterize chitosan-glutaraldehyde (Chi-Glu) copolymers.
• To investigate the sorption properties of Chi-Glu copolymers for p-nitrophenol (PNP) removal.
• To correlate sorption capacity with cross-linking density and reaction conditions.

Main Methods:

• Preparation of Chi-Glu copolymers under modified reaction conditions (temperature, pH, reagent ratios).
• Characterization using Fourier-transform infrared spectroscopy (FT-IR), CHN elemental analysis, and thermogravimetric analysis (TGA).
• Evaluation of sorption properties in aqueous solutions with p-nitrophenol at varying pH levels.

Main Results:

• CHN and TGA confirmed self-polymerized glutaraldehyde, indicating successful copolymerization.
• Sorption capacity increased with higher cross-linker content, with optimal performance at a 4:1 glutaraldehyde:chitosan mole ratio.
• PNP dye binding to chitosan was primarily through electrostatic interactions, evidenced by pH-dependent sorption.

Conclusions:

• Chitosan-glutaraldehyde copolymers can be effectively synthesized by modifying reaction conditions.
• Increased cross-linking density significantly enhances the sorption capacity for p-nitrophenol.
• The study provides insights into the structure-property relationships of Chi-Glu copolymers for pollutant remediation.