Fluorescent dendritic fibrous silica nano-microspheres for the sensitive recognition and efficient separation of 4-nitrophenol

Given the significant impact of the toxic compound 4-nitrophenol (4-NP) on health and safety, its detection and separation have become key research objectives. In this study, a dual-functional fluorescent probe (Naph-DFNS-PPD) for adsorption and separation was designed by surface functionalization of dendritic fibrous nano-silica (DFNS). DFNS was first synthesize, and then modified. NH₂-DFNS was obtained by the reaction of DFNS with amino-silane (APTES). Then, it was reacted with 4-bromo-1,8-naphthalic anhydride and 4-piperidine piperidine in consequence to integrate the fluorescent groups and the recognition groups. The obtained Naph-DFNS-PPD showed excellent sensitivity to 4-NP detection (LOD = 1.89 μM) and achieved an adsorption efficiency of 90.2 %, which benefited from the acid-base interaction driving mechanism. Specifically, the proton transfer between 4-NP and the probe can not only trigger fluorescence quenching for real-time monitoring but also promote the adsorption of 4-NP by the probe. This strategy establishes a system of multifunctional materials that combine recognition with pollutant fixation, providing a practical solution for environmental monitoring and remediation.