Schiff base stabilized palladium nanoparticles: Synthesis, characterization, catalytic degradation of organophosphorus pesticides, and fluorometric detection of Cr6+ in aqueous media

Abstract

As a stabilizing and reducing agent, the Schiff base (2-(4-(trifluoromethoxy)phenylimino)methyl)-6-methoxyphenol) was used to synthesize palladium nanoparticles (PdNPs) with an average particle size (12 ± 2 nm) and a spherical shape. The numerous methods, including UV–vis absorption spectroscopy, photoluminescence (PL), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) were used to characterize the PdNPs. The Schiff base capped PdNPs have FCC structure with 10 ± 3 nm particle size was estimated from XRD and TEM analysis. The catalytic, sensing, antibacterial, and antioxidant abilities of the created PdNPs were assessed. The findings demonstrated that PdNPs followed pseudo-first-order kinetics and had superior catalytic activity in the degradation of pesticides (monocrotophos (MCP), 99.9%) and chlorpyrifos (CLP), 98.2%) using NaBH4 as a reducing agent in 1 h reaction. PdNPs were still stable and exhibited a high catalytic activity with only a marginal decrease from maximum degradation (99.9% of MCP and 98.2% of CLP) using the fresh catalyst to 92.6% (MCP) and 90.1% (CLP) of the used catalyst (recycled after 5 times) was observed. Additionally, at a concentration range of 10–100 µM, the PdNPs demonstrated selective fluorescence sensing for Cr6+ metal ions in aqueous media. The significant antimicrobial action was also shown by the PdNPs against pathogens such S. aureus, B. subtilis, E. coli, P. aeruginosa, A. niger, and C. albicans. The PdNPs also demonstrated antioxidant activity in the DPPH free radical scavenging assay, with a 78.06% scavenging efficiency. This technique is efficient and cost-effective, and it may be used as an effective biological agent, sensor, and catalyst for a variety of environmental applications.