In situ modified nanocellulose/alginate hydrogel composite beads for purifying mining effluents

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Biobased adsorbents offer sustainability but face challenges in reusability and water flux.
• Nanocellulose and alginate composites show promise for water treatment applications.

Purpose of the Study:

• To develop and characterize nanocellulose/alginate composite hydrogel beads for efficient removal of cationic pollutants.
• To enhance the adsorbent properties for high-volume, high-flux water treatment.

Main Methods:

• Preparation of nanocellulose/alginate composite hydrogel beads (3-4 mm diameter, 99% porosity).
• Modification via in situ TEMPO-mediated oxidation to introduce carboxyl groups.
• Evaluation of pollutant removal using UV-vis spectroscopy and elemental analyses (EDS, XPS).
• Assessment of water flux using standard hydraulic conductivity measurements.

Main Results:

• Modified beads demonstrated efficient removal of Methylene Blue (91%) and Cd2+.
• A 3-fold increase in ion adsorption capacity was observed after modification.
• High water throughput rate of 17,000 L h⁻¹ m⁻² bar⁻¹ was maintained.
• The beads are suitable for 3-D column filters for large-volume water treatment.

Conclusions:

• TEMPO-mediated oxidation effectively functionalized nanocellulose/alginate beads for enhanced cationic pollutant removal.
• The developed hydrogel beads offer a sustainable and efficient solution for water purification.
• These beads are promising for industrial-scale water treatment applications under atmospheric pressure.