Imine functionalized cross-linked chitosan based bio-sorbent as a pH tunable platform for efficient dye adsorption

Area of Science:

• Materials Science
• Environmental Chemistry
• Polymer Science

Background:

• Wastewater contamination by dyes poses significant environmental challenges.
• Chitosan, a biopolymer, offers potential for developing effective dye adsorbents due to its functional groups.

Purpose of the Study:

• To synthesize and characterize a novel chitosan-based crosslinked gel (ChDBAG) for efficient dye removal.
• To evaluate the adsorption performance and regeneration capabilities of ChDBAG for various dyes.

Main Methods:

• Chitosan functionalization with 3,4-dihydroxybenzaldehyde and crosslinking with glutaraldehyde.
• Characterization using FTIR, UV-DRS, XRD, TGA, FE-SEM, BET, and XPS.
• Adsorption studies under varying pH, adsorbent dosage, and dye concentration, analyzed with isotherm and kinetic models.

Main Results:

• ChDBAG demonstrated high removal efficiencies (>95%) for both anionic and cationic dyes across different pH conditions.
• Maximum adsorption capacity for Congo Red reached 105.26 mg/g, fitting the Langmuir isotherm and pseudo-second-order kinetic model.
• The adsorbent was successfully regenerated and reused for up to ten cycles with maintained high efficiency.

Conclusions:

• ChDBAG is a highly efficient and sustainable adsorbent for removing diverse dyes from wastewater.
• The adsorption mechanism involves electrostatic interactions, hydrogen bonding, and π-π interactions.
• ChDBAG shows promise for practical applications in treating dye-polluted water.