Facile synthesis of Schiff base palladium (II) complex for efficient catalytic reduction of aromatic nitro compounds and organic dyes for wastewater remediation

Abstract

Organic pollutants, such as aromatic nitro compounds and synthetic dyes, pose a serious threat to the environment as they are often released without prior treatment. These organic pollutants are primarily carcinogenic and do not degrade over time, necessitating their monitoring and removal from wastewater. Several methods exist for the removal of these harmful substances, including photolysis, adsorption, membrane treatment, biological treatment, catalytic oxidation, and catalytic reduction. In this work, we have synthesized a Schiff base (SB1) and its palladium complex (Pd (II) Complex), and characterized them through various analytical techniques such as Fourier transform infrared, proton nuclear magnetic resonance, electrospray ionization mass spectrometry, ultraviolet–visible spectroscopy, energy dispersive x-ray analysis, elemental analysis, elemental mapping and scanning electron microscope. Theoretical calculations, for SB1 and Pd (II) Complex, such as structure optimization, molecular electrostatic potential, frontier molecular orbital and energy band gap were also carried out. We subjected the Pd (II) Complex for catalytic reduction and found it very efficient in reducing aromatic nitro compounds as well as synthetic organic dyes. The Pd (II) Complex reduces 4-nitrophenol, 4-nitroaniline, congo red and methyl orange in 9, 5, 8 and 4 min with rate constant value of 0.48, 0.54, 0.33, and 1.07 min⁻¹ respectively.