Fabrication of low cost thermoresponsive microgel@CuO catalyst for rapid reduction of methylene blue dye

Abstract

Azo dyes which are carcinogenic and mutagenic in nature are hazardous water pollutants. The present study details the catalytic reduction of methylene blue (MB) dye. In this research, the synthesis of microgels was achieved through free-radical emulsion polymerization by employing 2-hydroxyethyl methacrylate as a monomer as well as the crosslinker. The other monomers used in the synthesis of the microgels are styrene, acrylamide and N-vinylcaprolactam (NVCL). Three different grades of microgel have been synthesized by varying the amount of NVCL while keeping other monomer amounts constant. Further, copper-oxide nanoparticles have been incorporated into polymeric microgels through hydrothermal methods for catalytic reduction applications. Characterizations of both microgels and microgel-nanoparticle composites have been conducted using various techniques viz., Fourier transform infrared spectroscopy, powder X-Ray diffraction, dynamic light scattering, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The catalytic reduction of MB was studied by using ultraviolet-visible spectrophotometer. The catalytic reduction efficiency has been determined by optimizing the parameter effects of crosslinking, temperature responsive monomer feed, temperature and amount of reducing agent (NaBH4). Microgel nanocomposites have responded well in efficient catalysis at higher NVCL feed with moderate dose of NABH4. © The Polymer Society, Taipei 2024.