Bio-synthesized palladium nanoparticles using alginate for catalytic degradation of azo-dyes

Abstract

Abstract Palladium nanoparticles (PdNPs) were synthesized in a green way using sodium alginate functioning as both reductant and stabilizer. The formation of as-synthesized PdNPs was supervised by Ultraviolet–visible (UV–Vis) spectroscopy and confirmed by the surface plasmon resonance (SPR) band. The effect of several synthesis factors such as precursor ratio, solution pH, reaction time, and temperature were investigated by the factorial design of experiments in order to optimize the experimental conditions. The optimal synthesis parameters were achieved by heating 1.0 ml of 1.0% sodium alginate (SA), 3.0 ml of 10−2 mol·L−1 H2PdCl4 at 80 °C for a period of 30 min in a neutral reaction medium (pH = 6). High-resolution transmission electron microscope (HRTEM), energy dispersive X-ray (EDX) spectroscopy, selected area electron diffraction (SAED) pattern, X-ray powder diffraction (XRD), and dynamic light scattering (DLS) were used to confirm the uniform spherical shapes and high crystallinity of PdNPs with average particle size of (2.12 ± 1.42) nm. The SEM images show the distribution of PdNPs presented among the SA. FTIR spectra indicate that SA is a good capping agent to stabilize PdNPs for a long time. The catalytic degradation of model azo-dyes such as mono-azo (Cibacron Yellow FN–2R) and di-azo (Cibacron Deep Red S–B) were confirmed the catalytic activity of PdNPs. The PdNPs can accelerate the degradation rate by more than 80 and 10 times respectively as confirmed by kinetics constant (k) values.