Synthesis and characterization of a designed poly(ionic liquid-modified graphene oxide) nanocomposite: Evaluation of nitrate removal from water and antimicrobial properties

Abstract

Addressing the global challenge of water contamination, this study introduces a novel nanocomposite adsorbent—poly(ionic liquid-modified graphene oxide) (PIL-MGO)—designed to remove nitrates efficiently from water and combat microbial threats. Leveraging modified graphene oxide and vinyl imidazolium-based ionic liquid, this research synthesizes an adsorbent via a facile and cost-effective approach. The performance of PIL-MGO was rigorously analyzed through a series of characterizations, including Frontier transform infrared spectroscopy, field emitting scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis, revealing its robust structural composition and thermal stability. In our experimental exploration, the adsorbent showcased a remarkable nitrate removal efficiency of up to 97.53%, under optimal conditions of an initial pH of 5, room temperature, initial nitrate concentration of 30 mg/L, a contact time of 30 min, and an adsorbent dosage of 40 mg, with a significant selectivity for nitrate ions over competing anions. Moreover, regeneration of the adsorbent up to 7 cycles indicated only a marginal decline in adsorption efficiency. Furthermore, PIL-MGO demonstrated considerable antimicrobial properties against bacteria and fungi, indicating its dual utility in water purification and microbial inhibition. These findings suggest that the synthesized nanocomposite holds great promise for addressing environmental and health-related challenges posed by water pollutants. This study not only underscores the capabilities of PIL-MGO but also paves the way for further advancements in adsorbent technologies.

Highlights

• A novel nanocomposite was synthesized based on vinyl imidazolium ionic liquid and modified graphene oxide.
• This newly developed nanocomposite was evaluated as an adsorbent for the removal of nitrate ions from water, demonstrating high removal efficiency.
• The adsorbent exhibited notable selectivity for nitrate ions, effectively distinguishing them from competing anions such as chloride, bicarbonate, sulfate, and phosphate.
• The adsorption kinetics of the nanocomposite were best described by the pseudo-second-order kinetic model, and the adsorption isotherm aligned well with the Langmuir model.
• Investigation of the nanocomposite antimicrobial activity displayed considerable inhibitory effects against both bacteria and fungi.