Synthesis of visible light-responsive cuprous oxide/sunflower stem pith hybrid materials for detoxification of methylene blue.

The detoxification of dye-contaminated water by photocatalysis has become a research priority. Here, a novel hybrid material, cuprous oxide/sunflower stem pith (Cu ₂ O/SSP), was successfully synthesized in situ, using copper hydroxide gel, prepared by ion exchange, as the precursor to Cu ₂ O. The presence of Cu ₂ O nanoparticles on the SSP was confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction analyses. Using methylene blue (MB) as the target pollutant, Cu ₂ O/SSP delivered excellent adsorption-photocatalytic degradation and was readily photoregenerated. Cu ₂ O/SSP removed 72.7% of MB after 60 min under visible light irradiation, an increase of 15.6 % compared with unmodified SSP. SSP plays three roles in the removal of MB: it acts as an adsorbent for the MB, a carrier for the Cu ₂ O nanoparticles and it also inhibits photocorrosion of Cu ₂ O. The mechanism of adsorption-photocatalysis by Cu ₂ O/SSP was investigated and a description of the mechanism is provided. This study paves the way for the detoxification of dye-containing wastewater using hybrid biomass materials.