Novel in-situ synthesis of copper oxide nanoparticle in smart polymer microgel for catalytic reduction of methylene blue

Abstract

The present study involves the synthesis of poly-(N-isopropylmethacrylamide-co-methacrylic acid) [p(NiPmA-mAc)] microgels for the stabilization of copper oxide nanoparticles (CuO NPs) via free radical precipitation approach and synthesized material as a catalyst for catalytic degradation of methylene blue (MB) dye. Results clearly indicate that p(NiPmA-mAc) microgel not only serves as an excellent micro-reactor but also works as an effective stabilizing / fabricating medium for the successful synthesis of CuO NPs. UV–Vis spectra of CuO-[p(NiPmA-mAc)] showed the maximum peak was observed at 400 nm. Scanning electron microscopic (SEM) and X-ray diffraction (XRD) analysis showed spherical morphology of in-situ synthesized CuO NPs with crystalline size of 20 ± 4 nm. Different parameters which affect catalytic reduction reactions such as pollutant/catalyst dose, reductant concentration and effect of time were investigated. Results showed that the apparent rate constant for catalytic reduction of MB was 0.5307 min−1. The application of the CuO NPs loaded p(NiPmA-mAc) microgel catalyst for catalytic degradation of MB has shown excellent results with complete degradation (100%) within 15 min. Further, the recyclability of the CuO-[p(NiPmA-mAc)] catalyst has shown promising results during four consecutive cycles thus, confirming its stability.