Nanocomposite membranes with Au nanoparticles for dialysis-based catalytic reduction-separation of nitroaromatic compounds

Abstract

Apart from the fact that nitroaromatic compounds (NARs) have toxic and mutagenic characteristics, they are also essential substrates for the synthesis of aromatic amines (AAMs). In this context, the present study presents a new approach that enables NAR-contaminated wastewaters to be treated as a reagent for the synthesis of AAMs. It involves the fabrication of anion exchange membranes with Au nanoparticles (AuNPs) that simultaneously reduce 4-nitrophenol (4-NP) and separate the resultant 4-aminophenol (4-AP) via. the dialysis mechanism. The nanocomposite membranes were prepared by amino-modification of poly(vinyl chloride) films obtained in the presence of cyclohexanone (CH) or tetrahydrofuran (THF), followed by Au(III) reduction coupled-adsorption. The nanomaterials were analysed using scanning transmission electron microscopy (STEM) and Fourier-transformation infrared spectroscopy (FT-IR). The catalytic reaction was carried out in a dialysis unit, where the concentration of 4-NP in the wastewater, and the concentration of separated 4-AP were monitored using UV-Vis spectroscopy. The nanocomposite membranes formed using THF effectively reduced the 4-NP and separated the resultant 4-AP. The yield of the 4-NP conversion reached 80% with a rate constant of 11.30 10-3 min-1. Based on the results, THF contributed to the formation of diffusion paths in which the 4-NP was simultaneously separated and reduced.