N-(2-(2-pyridyl)ethyl)chitosan: Synthesis, characterization and sorption properties

Area of Science:

• Materials Science
• Environmental Chemistry
• Analytical Chemistry

Background:

• Chitosan, a natural polymer, has limited affinity for certain heavy metal ions.
• Modification of chitosan can enhance its chelating properties for precious and transition metals.

Purpose of the Study:

• To develop a modified chitosan, N-2-(2-pyridyl)ethylchitosan (PE-chitosan), with improved metal ion sorption capabilities.
• To evaluate the sorption performance of PE-chitosan for various metal ions, including precious and transition metals.

Main Methods:

• Synthesis of PE-chitosan via a "synthesis in gel" approach using 2-vinylpyridine and chitosan.
• Investigation of sorption properties and capacities for Pt(IV), Pd(II), Au(III), Cu(II), and Ag(I) ions.
• Application of PE-chitosan for preconcentration of Au(III) in atomic absorption spectroscopy analysis.

Main Results:

• PE-chitosan demonstrated significantly higher affinity for Pt(IV) and Pd(II) compared to unmodified chitosan.
• Maximum sorption capacities for PE-chitosan in 0.1M HCl were 5.56 mmol/g for Au(III), 3.67 mmol/g for Pd(II), and 2.75 mmol/g for Pt(IV).
• Sorption capacities for transition metals (Cu(II), Ag(I)) were 1.5-2.6 times higher than chitosan, reaching 1.50 mmol/g and 1.53 mmol/g, respectively.

Conclusions:

• PE-chitosan exhibits superior sorption performance for precious and transition metal ions over unmodified chitosan.
• The developed PE-chitosan is effective for preconcentrating gold ions for sensitive atomic absorption spectroscopy analysis.
• This modified chitosan offers a promising material for metal ion remediation and analytical preconcentration.