The development of a multifunctional high-swelling alginate silver nanocomposite for water decontamination

Introduction

Sodium alginate nanocomposites containing metallic nanoparticles have found various biomedical and environmental applications. These materials are easy to prepare and sustainable. In recent years, such materials have been widely used for the adsorption/degradation of toxic substances such as organic dyes, pharmaceuticals, heavy metals, etc. In this project, we have developed reusable sodium alginate–poly sodium acrylate silver nanocomposites with a high swelling capacity for enhanced degradation of toxic organic materials.

Methodology

Polymer beads based on sodium alginate–poly sodium acrylate containing silver nanoparticles were synthesized by means of a combination of ionotropic crosslinking in calcium chloride solution and free-radical polymerization using ammonium persulfate. The beads were characterized using various advanced methods such as UV-Vis absorption spectroscopy, Fourier transform infra-red spectroscopy, and electron microscopy. The swelling capacity was evaluated using the gravimetric method. The antibacterial property was studied using the incubation method against three clinically important pathogens: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The catalytic degradation of Congo red and 2-nitrophenol achieved by the beads was studied in the presence of sodium borohydride.

Preliminary results

The nanocomposite beads were spherical and porous and exhibited a high swelling capacity due to the presence of poly sodium acrylate. A strong plasmon resonance (SPR) peak at around 400 nm confirmed the presence of silver nanoparticles. The nanocomposites were effective against the growth of E. coli and P. aeruginosa. Almost 100% degradation of Congo red and 2-nitrophenol was achieved in about 30 min.

Conclusion and work in progress

The nanocomposite beads showed both antibacterial and catalytic properties, showing promise for detoxification of hospital wastewater in the future. The reusability of the material and the use of real-life samples are currently in progress.