Physicochemical properties of TIO2, ZrO2, Fe3O4 nanocrystalline adsorbents and photocatalysts

Nanostructured metal oxides and composites based on them are promising materials for use in different areas, such as electronics, sensors, ceramics, adsorbents, catalysts, and others. However, many studies about the synthesis conditions influence of various metal oxides and their composites on their physicochemical properties and the purposeful control of these properties remain under question. The article considers the conditions for obtaining nanomaterials and nanocomposites of metal oxides (TiO2, ZrO2, Fe3O4) on their properties. The relevance of this direction is due to the promising usage of metal oxide nanomaterials and especially nanocomposites as adsorbents and photocatalysts for purifying wastewater from pollutants of different nature. TiO2, ZrO2, Fe3O4 nanomaterials and nanocomposites based on them were obtained by various wet synthesis methods (sol-gel, hydrothermal, chemical deposition, and impregnation). The influence of the main synthesis parameters of TiO2, ZrO2, Fe3O4 nanomaterials, and nanocomposites on their physicochemical properties were studied by X-ray diffraction, X-ray photoelectron spectroscopy, electron spectroscopy, and Raman spectroscopy, as well as low-temperature nitrogen adsorption-desorption. It is shown that the synthesis method significantly affects the physicochemical properties of metal oxide nanomaterials. It is established that a given modification of TiO2 or ZrO2 can be obtained by adjusting the crystallite size during the synthesis. It is found that the synthesized TiO2/SnO2, TiO2/CdS, activated carbon/ZrO2 and clay minerals/Fe3O4 nanocomposites in all cases have better adsorption and photocatalytic properties compared to individual metal oxide phases. To study the adsorption-catalytic properties of TiO2, Fe3O4 metal oxides and their composites, the traditional organic molecules Methylene Blue and Congo Red were chosen; to study the ion-exchange characteristics of ZrO2 metal oxides and its composites, phosphate and iron (III) ions were selected. Thus, modification of individual phases of metal oxides allows controlling their adsorption, ion exchange and photocatalytic properties. This is caused by the synergistic effects observed in nanocomposites related to the improvement of textural and surface characteristics and the formation of multiple acid-base centers on their surface.

Automated summary

Nanostructured metal oxides and their composites have promising applications in various fields, and the synthesis conditions significantly affect their physicochemical properties. By studying the synthesis parameters, the adsorption, ion exchange, and photocatalytic properties of these materials can be controlled.