AbstractFluorescent carbon dots (CDs) derived from natural biomass have attracted considerable attention due to the superior characteristics of low‐cost, large‐scale, renewability, and excellent biocompatibility. In this work, novel orange‐red fluorescent carbon dots (N‐CDs) were successfully designed and prepared via hydrothermal method by using Peony seed residue and o‐phenylenediamine as precursors. The obtained N‐CDs exhibited good aqueous solubility, outstanding fluorescence properties, and high photostability. Moreover, the fluorescence intensity of N‐CDs at 594 nm exhibited a linear change towards Fe3+ in the range of 0.0–50.0 μM, and the detection limit was 20 nM. For fast and efficient Fe3+ sensing, two kinds of solid‐phase fluorogenic test strips and nanofibrous film composited with N‐CDs were fabricated. Furthermore, solid phase materials composited PVDF with N‐CDs (N‐CDs@PVDF) demonstrated outstanding properties in simultaneous Fe3+ adsorption and detection, providing an integrative solution for the detection and decontamination of heavy metal ions