Hydrothermal Synthesis of Zinc Silicate Nanomaterials for Organic Dyes Removal from Aqueous Solutions

In recent years, the extensive use of organic dyes has caused great pollution to the water environment. Zinc silicate with excellent adsorption and photocatalytic properties has been widely used in the treatment of organic dye wastewater. Therefore, we successfully prepared zinc silicate nanomaterials by simple hydrothermal method using zinc sulfate heptahydrate (ZnSO₄·7H₂O) and tetraethyl orthosilicate (TEOS) as raw materials, and cetyltrimethylammonium bromide (CTAB) as surfactant, and applied them to the treatment of organic dye wastewater. The composition, morphology and specific surface area of zinc silicate nanomaterials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) method. The results show that the phase composition of the products has a transformation from hemimorphite Zn₄Si₂O₇(OH)₂·H₂O to vermiculite Zn₂SiO₄, and the morphology has also an obvious change from nanosheets, nanoflowers to nanoparticles with the increase of TEOS content. The specific surface area and pore volume are 199.8 m²/g and 0.441 cm³/g for the flower-like zinc silicate nanomaterials. The zinc silicate nanomaterials show excellent adsorption and photocatalytic properties for organic dyes from aqueous solutions, and the maximum removal efficiencies can reach 89.8% and 96.2% for rhodamine B (RhB) and methylene blue (MB), respectively.