Synthesis of Nanocomposite Hydrogels Based on Sodium Alginate for Effective Removal of Methylene Blue and Antibacterial Applications

Hypothesis: Water pollution has been emphasized as one of the major threats to environment and human health. In this regard, various adsorbents with high adsorption capacities and rapid sorption rates have been synthesized. In the present study, we report the synthesis, structure characterization and methylene blue adsorption of a novel hydrogel nanocomposite based on sodium alginate and silver nanoparticles.
The hydrogel nanocomposite was prepared using grafting of acrylic monomers onto sodium alginate by using ammonium persulfate (APS) as free radical initiator and methylene bisacrylamide (MBA) as crosslinker in the presence of Ag nanoparticles synthesized by an in situ chemical reduction method. The structure of hydrogel nanocomposite was then characterized by FTIR, SEM, TEM, EDX, XRD, and TGA techniques.
Findings: The adsorption behavior of methylene blue dye on the synthesized hydrogel nanocomposites was studied. In order to obtain the maximum adsorption capacity, the effects of various parameters were optimized with respect to dye adsorption capacity of hydrogel nanocomposites in detail. The thermodynamic parameters also demonstrated that the dye adsorption process was spontaneous and exothermic in nature. Moreover, the hydrogel nanocomposite adsorbents showed a high selectivity for the adsorption of cationic dyes with a high adsorption capacity of 168 mg/g. The antibacterial activity of the nanocomposites was examined against E. coli using disk diffusion method. In general, the results indicated that the synthesized hydrogel nanocomposite with antibacterial and dye adsorption properties is a potential material for medical applications as well as wastewater treatment.