Fast in-situ synthesis of mesoporous Prussian blue-silica nanocomposite for superior silver ions recovery performance

Abstract

BACKGROUND

Mesoporous-nanostructured silica-Prussian blue composite is a highly potential material for silver ions removal and recovery from wastewater. Intense interest has been shown in the use of Prussian blue (PB), one of the important coordinated materials and its analogues in removal of toxic and valuable ions.

METHODS

The micro-emulsion template method enables the synthesis of Prussian blue (PB) within silica pores, yielding a nanostructured mesoporous silica-PB composite. This rapid synthesis technique allows for the direct fabrication of the composite from mixed precursor solutions within minutes. The resulting material is effective for selectively extracting silver ions from wastewater at a specific pH level.

RESULTS AND DISCUSSION

In summary, the synthesized SiO₂-Prussian blue composite was extensively analyzed using various techniques including XPS, HR-TEM, SEM, STEM-EDX elemental maps, TGA/TDA, and N₂ adsorption/desorption measurements. The composite exhibited a BET surface area of 203 m² g⁻¹ and a total pore volume of approximately 0.283 cm³ g⁻¹with mesopores centered around 20 nm. This mesoporous SiO₂-Prussian blue demonstrated significant effectiveness in removing silver ions, with a maximum adsorption capacity of 107.5 mg g⁻¹. The Langmuir and Sips isotherms showed the best fit among various adsorption isotherm types, with R² values exceeding 0.984. Additionally, kinetic analyses revealed that the pseudo-second-order model accurately described the adsorption of silver ions onto the synthesized adsorbent. The nano-particles exhibit remarkable long-term stability, maintaining good reproducibility even after five regeneration cycles. © 2024 Society of Chemical Industry (SCI).