Potential of cobalt and cobalt oxide nanoparticles as nanocatalyst towards dyes degradation in wastewater

We herein report the morphology and photocatalytic properties of Co and Co3O4 nanoparticles synthesized using microwave and reductive chemical heating methods. The synthesized nano-scale particles were characterized using UV–visible (UV–Vis) absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction spectroscopy (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). Photocatalytic degradation of murexide dye and erichrome blak-T (EBT) dye in wastewater in the presence of sunlight was investigated using the synthesized nanoparticles. Chemically synthesized Co-nanoparticles gave highest degradation efficiency (43.6%) towards murexide dye at 25 mg loading and 40 mins exposure time, while Co3O4 nanoparticles (microwave synthesized) gave the highest degradation efficiency (39.4%) at 10 mg loading and 40 mins sunlight exposure time in EBT. A higher photodegradation efficiency is postulated at a longer exposure time under sunlight irradiation. The study therefore concluded that the microwave synthesized nanoparticles would be preferred for remediation of dyes containing wastewater since it is greener, faster to make, cheap and gave photocatalytic degradation efficiency that compared favourably with that of the chemical method. [Display omitted] •Morphology and catalytic properties of Co and Co3O4 nanoparticles (NPs) were reported.•Microwave and reductive chemical heating methods were used for the NPs preparation.•The nanoparticles were active against Murexide and Eriochrome Black-T degradation.•The degradation increased with time and concentration.•The NPs served as adsorbent for the treatment of industrial wastewater containing dye.