Green NiO nanoparticle-integrated PVA-alginate hydrogel: potent nanocatalyst for efficient reduction of anthropogenic water pollutants.

Hydrogel nanocatalyst composed of nickel oxide (NiO) nanoparticles embedded in PVA-alginate hydrogels were potentially explored toward the reduction of anthropogenic water pollutants. The NiO nanoparticles was accomplished via green method using waste pineapple peel extract. The formation of the nanoparticles was affirmed from different analytical techniques such as UV-Vis, FTIR, XRD, TGA, FESEM, and EDS. Spherical NiO nanoparticles were obtained having an average size of 11.5 nm. The nano NiO were then integrated into PVA-alginate hydrogel matrix forming a nanocomposite hydrogel (PVALg@ NiO). The integration of nano NiO rendered an improved thermal stability to the parent hydrogel. The PVALg@ NiO hydrogel was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP), potassium hexacyanoferrate (III), rhodamine B (RhB), methyl orange (MO), and malachite green (MG) in the presence of a reducing agent, i.e., NaBH4. Under optimized conditions, the reduction reactions were completed by 4.0 min and 3.0 min for 4-NP and potassium hexacyanoferrate (III), respectively, and the rate constant was estimated to be 1.14 min-1 and 2.15 min-1. The rate of reduction was found to be faster for the dyes and the respective rate constants were be 0.17 s-1 for RhB, MG and 0.05 s-1 for MO. The PVALg@ NiO hydrogel nanocatalyst demonstrated a recyclability of four runs without any perceptible diminution in its catalytic mettle. The efficacy of the PVALg@ NiO hydrogel nanocatalyst was further examined for the reduction of dyes in real water samples collected from different sources and the results affirm its high catalytic potential. Thus, this study paves the path for the development of a sustainable hydrogel nanocatalyst for reduction of hazardous pollutants in wastewater treatment.

Bio-valorization of Tagetes floral waste extract in fabrication of self-healing Schiff-base nanocomposite hydrogels for colon cancer remedy.

The drastic boom in floriculture and social events in religious and recreational places has inevitably led to generation of tremendous floral waste across the globe. Marigold (Tagetes erecta) is one of the most common loose flowers offered for the same. Generally discarded, these Tagetes floral wastes could be valorized for biogenic syntheses. In this study, we have utilized the floral extract towards green synthesis of nano ZnO, the formation of which was affirmed from different analytical techniques. Bionanocomposite Schiff-base hydrogel composed of chitosan and dialdehyde pectin was fabricated by the facile strategy of in situ polymer cross-linking, and the ZnO nanoparticles were embedded in the hydrogel matrix. The hydrogel exhibited remarkable self-healing ability. The antioxidant and anti-inflammatory activities were enhanced owing to nano ZnO. Furthermore, it was hemocompatible and biodegradable. A controlled release drug profile for 5-fluorouracil from the hydrogel was accomplished in the colorectum. The exposure of the drug-loaded nanocomposite hydrogel demonstrated improved anticancer effects in HT-29 colon cancer cells. The findings of this study altogether put forth the successful biovalorization of Tagetes floral waste extract for colon cancer remedy.