Preparation And Applications Of Novel WO₃ Nanomaterials

Dyes are indispensable materials in different industries of society,as well as the main components of one of the most polluted wastewaters.It will pose a serious threat to human health and normal biological growth.Therefore,the development of sensitive and accurate detection methods for dye molecules and the highly efficient removal of them in wastewater are of great significance for environmental protection and biological research.In this dissertation,novel WO₃ nanocomposites were studied.Due to their unique structure and superior performance,combined with surface-enhanced Raman spectroscopy,the research on the removal and sensitive detection of dyes was carried out.The details are summarized as follows:?1?Preparation of a novel WO₃ nanomaterials based on TiO₂ and its Adsorption to Dye Molecules.The WO₃/TiO₂ heterostructure was prepared by hydrothermal method with TiO₂ nanotubes as the substrate,and WO₃ nanoflower material was obtained.The prepared WO₃ nanoflower material was applied to remove malachite green?MG?from aqueous solutions.The experimental parameters such as pH value,equilibration time,initial concentration of MG and ionic strength on the adsorption of MG were investigated.Results showed that the largest adsorption capacity of WO₃ nanoflower material were 311.25 mg·g at room temperature.And the optimum reaction conditions of the adsorption process as follows:the optimum reaction time is 2hour,the optimum pH is 7.Adsorption kinetics and Adsorption isotherm were adopted to demonstrate and explain the adsorption selectivity of the WO₃ nanoflower material towards target molecule.Langmuir isotherm model fitted the equilibrium data better than Freundlich model.And the pseudo-second-order equation well described the adsorption of MG on the WO₃ nanoflower material.?2?Study on SERS detection of dye molecules based on Au/WO₃/TiO₂ nanosheets.Owing to the nanoflower structure,a localized surface plasmon resonance is generated on the surface of Au/WO₃/TiO₂ nanosheets,which brings about multiple enhanced three-dimensional electromagnetic fields.An enhanced factor of 3.6×10⁶ is achieved.The spot-to-spot change in SERS intensity is less than 15%,and the SERS substrate can be preserved for at least 50 days.The analysis of dyes in real samples gives a recovery rate of 94.33-115.6%,indicating its potential applications in environmental analysis.