Facile synthesis and characterization of palladium-loaded hydrophilic cryogels for catalytic and bactericidal applications

Herein, superporous hydrophilic cryogels of poly(acrylic acid) p(AAc) have been synthesized via free radical polymerization at freezing conditions by varying the concentration of monomer and cross-linker. A simple reduction method has been adopted to incorporate palladium nanoparticles (PdNPs) in p(AAc) pores. The as-synthesized hybrid cryogels were characterized through FTIR, XRD SEM, EDX, and TEM techniques. To study the water absorption capacity of as-synthesized cryogels, a swelling degree test has been conducted. The catalytic performance of the modified cryogels was evaluated for the removal of methylene blue (MB) dye using NaBH₄ as a reducing agent. Different experimental parameters, for example, pH, amount of catalyst, and temperature were investigated to achieve optimized catalytic conditions. In brief, the catalytic activity of 97-AAc (3%) Pd-p(AAc) cryogel was more significant as compared to 95-AAc (5%) Pd-p(AAc)– and 93-AAc (7%) Pd-p(AAc)–based cryogels. This might be due to the presence of a superporous structure enriched with optimized Pd distribution to facilitate maximum retention of dye molecules. Furthermore, the bactericidal potential of the cryogels was evaluated by the optical density (OD) method against both gram-positive and gram-negative bacteria. Pd-p(AAc) cryogels exhibited enhanced antibacterial activity due to the incorporation of palladium nanoparticles within the super porous network. The as-synthesized nanocomposite cryogels were found brilliant and capable of further processing in wastewater treatment in the biomedical domain.