Rapid ecosynthesis of TiO2@CuO@Chromite nanocatalyst for environmentally friendly applications: solventless cyanation of aldehydes and high efficient treatment of sewage waters

Background Due to the large surface area of green-synthesized TiO2@CuO@Chromite nanocatalysts (NCs) and accumulations of bioactive phytochemicals on its surface, it was used for an efficient and safe synthesis of nitriles and also an environmentally friendly process of water treatment. For the first time, a rapid, economic, one-pot, solventless and safe protocol is presented for ecosynthesis of TiO2@CuO@Chromite nanocatalysts (NCs) to efficient, ligand-free and solventless synthesis of aromatic nitriles through the cyanation of aldehydes at room temperature. Furthermore, the eco-NCs were used as a potent adsorbent for physical and biological treatment of sewage waters collected around the natural and residential area of northern parts of the Soran city in Iraq at room temperature. Results The structural elucidation of the NCs using the SEM (scanning electron microscopy), Cross-sectional EDS (electron dispersive spectroscopy), elemental mapping analysis, XRD (X-ray diffractions) and BET (Brunauer–Emmett–Teller) for detection of specific surface area of eco-NCs confirmed the formation of NCs with a large surface area. Application of green TiO2@CuO@Chromite NCs in solventless synthesis of aromatic nitriles shows high efficiency, time saving, economical aspect and ecofriendly and safe methodology. Also, the treatment process of sewage waters monitored using UV–Vis double beam spectrophotometer, optical microscopy and antibiogram tests demonstrated an efficient ability for the eco-NCs in physical and biological treatment of sewage samples. Conclusions The NCs employed in both ligand and solventless highly efficient and safe synthesis of aromatic nitriles through the cyanation of aldehydes at room temperature demonstrated the production of aryl nitriles in very good-to-excellent yields. This protocol indicated a green alternative to the existing methods since the reaction proceeds in solventless medium in the absence of any ligand and organic solvent with simple work-up procedure, low temperature, higher yield and shorter reaction time. Further, it was used in the physical and biological treatment of the real samples of sewage waters collected around the natural and residential area of northern parts of Iraq at room temperature, which shows a very good treatment ability in this process.