Urban air quality monitoring with silane-grafted rGO filters for high-performance PM₂.₅ particulate retention and enhanced sensing

The escalating global burden of atmospheric pollution, particularly particulate matter (PM₂.₅), necessitates intelligent particulate retention strategies that surpass conventional passive technologies. This study investigates the engineering of a synergistic filter medium using reduced graphene oxide (rGO) functionalized with (3-aminopropyl) triethoxysilane (APTES). Through a 15-day ambient sampling campaign (n = 3 for each filter type), we evaluate the morphological and chemical retention performance of unmodified, rGO-coated, and amine-functionalized (rGO-NH₂) quartz filters. Quantitative ICP-OES analysis revealed that rGO-NH₂ filters achieved a 320% increase in lead (Pb) retention and a 280% increase for cadmium (Cd) compared to unmodified filters. This enhancement is attributed to the synergistic effect of a nanotextured surface and the chelating capabilities of grafted amine groups. Furthermore, the functionalized composite serves as an active substrate for Laser-Induced Breakdown Spectroscopy (LIBS), amplifying optical emission signals by up to 300% and enabling rapid, semi-quantitative pollution monitoring. This dual-function material presents a robust platform for next-generation urban air quality management.