Silane-grafted Nano-TiO₂ Air Monitoring Filters for Enhanced PM2.5 Filtration and Detection in Urban Atmospheres
J. Environ. Nanotechnol., Volume 14, No 4 (December 2025) pp. 153-164
Abstract
The global health risks posed by fine particulate matter (PM2.5) demand advanced materials that integrate high-efficiency filtration with real‑time sensing capabilities. Herein, the fabrication and validation of a dual-function air filtration and sensing substrate based on aminosilane-grafted titanium dioxide (TiO2) nanoparticles are reported. TiO2 nanoparticles were modified with (3‑aminopropyl)triethoxysilane (APTES) to achieve robust surface immobilization and introduce terminal amine (–NH2)-based chemical affinity. Scanning electron microscopy (SEM) revealed a transformation from smooth to rough granular morphology; energy‑dispersive X‑ray spectroscopy (EDX) detected a silicon (Si) peak and a nitrogen (N) peak consistent with amine groups; Fourier transform infrared spectroscopy (FTIR) verified Ti–O–Si bond formation and N–H bending vibrations; and X‑ray diffraction (XRD) showed retention of anatase TiO2 crystallinity along with a concurrent amorphous siloxane surface network. A 15‑day ambient PM2.5 sampling demonstrated markedly enhanced collection performance of APTES–TiO2 compared with pristine TiO2 and unmodified filters. Inductively coupled plasma optical emission spectroscopy (ICP‑OES) quantification provided definitive evidence that amine functionalities induce chemisorptive capture, yielding significantly higher retained masses for metallic species (including Zn, Cu, Pb) and carbonaceous aerosols. Laser‑induced breakdown spectroscopy (LIBS) measurements exhibited nanostructure‑enhanced LIBS (NELIBS) signal amplification, and the LIBS intensities correlated strongly and positively with ICP‑OES concentrations, validating LIBS as a rapid proxy for mass loading. Together, these results establish the APTES–TiO2 composite as an effective dual‑function substrate that combines superior chemical capture with optical signal enhancement, offering a practical pathway toward next‑generation active monitoring systems for sensitive, near‑real‑time analysis of airborne contaminants.
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Reference
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