pH-sensitive cellulose/chitin nanofibrillar hydrogel for dye pollutant removal

Area of Science:

• Materials Science
• Environmental Science
• Polymer Chemistry

Background:

• Developing sustainable materials for wastewater treatment is crucial.
• Biopolymeric nanofibrils offer unique properties for advanced material design.
• pH-responsive materials can enhance contaminant removal and recovery processes.

Purpose of the Study:

• To synthesize a novel pH-sensitive hydrogel using chitin and cellulose nanofibrils.
• To evaluate the hydrogel's capacity for removing ionic contaminants.
• To assess the hydrogel's reusability and potential for wastewater treatment applications.

Main Methods:

• Preparation of a polyelectrolyte complex from chitin and cellulose nanofibrils.
• Cross-linking the complex using citric acid in an aqueous system.
• Testing the hydrogel's swelling behavior and surface charge conversion in response to pH.
• Evaluating the hydrogel's adsorption capacity for anionic (AO) and cationic (MB) dyes.
• Assessing the hydrogel's performance over multiple reuse cycles.

Main Results:

• A structurally stable, pH-sensitive biopolymeric nanofibrillar hydrogel was successfully synthesized.
• The hydrogel demonstrated rapid changes in swelling degree and surface charge with varying pH.
• High ionic dye removal capacities were achieved: 372.0 mg/g for AO and 140.5 mg/g for MB.
• The hydrogel maintained over 95.1% contaminant removal efficiency after 5 reuse cycles, facilitated by pH-controlled desorption.

Conclusions:

• The eco-friendly, pH-sensitive hydrogel exhibits excellent performance in removing ionic contaminants.
• Its ability to switch surface charge with pH enables efficient contaminant desorption and reuse.
• This biopolymeric hydrogel shows significant potential for sustainable and cost-effective wastewater treatment.