New hydrogels based on modified chitosan as metal biosorbent agents

Area of Science:

• Materials Science
• Environmental Chemistry
• Polymer Chemistry

Background:

• Chitosan, a biopolymer, is a promising material for environmental applications.
• Developing sustainable and biodegradable materials for heavy metal remediation is crucial.
• Modified chitosan hydrogels offer tunable properties for pollutant adsorption.

Purpose of the Study:

• To synthesize and characterize novel green biodegradable hydrogels based on modified chitosan.
• To investigate the adsorption efficiency of these hydrogels for various heavy metal ions (Cu(II), Co(II), Zn(II), Hg(II), Pb(II)).
• To evaluate the influence of pH on the metal adsorption performance of the hydrogels.

Main Methods:

• Synthesis of hydrogels (A1, A2) via chitosan modification with specific dialdehydes.
• Characterization using Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), and X-ray diffraction.
• Adsorption experiments conducted in aqueous solutions at varying pH levels.

Main Results:

• Successful preparation and characterization of two new chitosan-based biodegradable hydrogels.
• Demonstrated pH-sensitive adsorption behavior for multiple heavy metal ions.
• Hydrogel A2 exhibited superior adsorption capacity for Hg(II) ions, particularly at pH 5.

Conclusions:

• The synthesized chitosan-based hydrogels are effective and biodegradable materials for heavy metal removal.
• The pH-dependent performance highlights their potential for selective metal ion adsorption.
• Hydrogel A2 shows significant promise for the remediation of mercury contamination.