N-myristoyltaurine capped copper nanoparticles for selective colorimetric detection of Hg2+ in wastewater and as effective chemocatalyst for organic dye degradation

Abstract

The discharge of organic dyes and hazardous heavy metals from diverse industries into the environment has become a serious problem. Herein, we report that N-myristoyltaurine capped copper nanoparticles (CuNPs) speeds up the decolorization of dye effluents in the presence of sodium borohydride (NaBH4). The decolorization followed by UV–visible spectroscopy revealed that the reaction follows pseudo first-rate kinetics. All the tested dyes decolorized in less than 3 min. As a result of decolorization, the toxicity of the dye effluents decrease considerably, which was proved by seed germination assay. Further, the surface plasmon resonance property of the CuNPs was explored for selective and sensitive detection of hazardous mercury ions in sewage water (SW) and artificial cerbospinal fluid (aCSF). In the presence of Hg2+, galvanic displacement reactions promote the aggregation and the color change of CuNPs from wine red to grayish white. On the basis of colorimetric change, a minimum concentration of 15 μM of Hg2+ can be detected by the naked eye. The spectrophotometric detection method showed a detection limit of 0.1125 μM. Interference studies suggest that CuNPs is highly sensitive to Hg2+ ions. Recovery experiments proved that CuNPs quantitatively detect the spiked Hg2+ ions in tap water, SW and aCSF with an acceptable recovery range of 92 to 113%. Overall, the experimental outcomes suggest that the CuNPs could be deployed as a catalyst to decolorize dye effluents and as a colorimetric probe for mercury detection in wastewater.