Synthesis of g-C₃N₄@WO₃ nanocomposites for dye adsorptive removal in water medium: Equilibrium and kinetics studies

Abstract

In this research, WO₃, g-C₃N₄, and g-C₃N₄@WO₃ nanocomposites were synthesized from Na₂WO₄.2H₂O and urea precusors via the hydrothermal method in a strong acid medium. Physico-chemical characteristics of WO₃, g-C₃N₄, and g-C₃N₄@WO₃ nanocomposites were examined by means of XRD, Raman, FTIR, FE-SEM, BET, and UV-Vis spectroscopy. The produced materials were then applied for studying adsorptive removal of methylene blue (MB) as a model pollutant from aqueous solutions. The results showed that g-C₃N₄@WO₃ nanocomposites were successfully synthesized, with a hexagonal shape and an average crystal size of in the range of 15.4–20.7 nm. The surface area (68.3 m²/g) of g-C₃N₄@WO₃ nanocomposites was 2.37 times higher compared to sole WO₃, and g-C₃N₄@WO₃ composites were mesoporous materials with a typical average pore diameter of 4.5 nm. It was revealed that the MB adsorption process occurred extremely quickly, reaching equilibrium after only about 20 min, with a maximum uptake of MB of 190 mg/g which was significantly higher than other adsorbents. The adsorption process was followed the first-order-kinetics model and the adsorbent showed high durability in adsorbing MB, with a slight decline in adsorption efficiency after 4 cycles (from 98.7% to 95.9%). This research provides an easy method for producing high adsorption capacity nanocomposite which can be applied for efficient removal of MB from water.

Graphical Abstract

Keywords:

• Graphitic carbon nitride (g-C₃N₄)
• tungsten oxide
• adsorption
• dyes
• equilibrium and kinetics modeling

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

All data generated or analyzed during this study are included in this published article.

Additional information

Funding

This research was financially supported by the research program of the Ministry of Education and Training under the grand number B2021-XDA-07.