Elucidation of the mechanisms of VOC removal in botanical filters during indoor air treatment in a test chamber

• Whole plant cuttings showed a better VOC removal compared to roots alone. • Acetone removal was difficult to detect due to absorption in the growth medium. • Large-leaved species like Epipremnum aureum showed higher VOC removal. • Root systems and microorganisms enhance VOC removal via phytoremediation. The removal of volatile organic compounds (VOCs) from indoor environments using plants has attracted increasing attention as an effective natural mitigation strategy. In this study, five indoor plant species ( Epipremnum aureum, Syngonium podophyllum, Spathiphyllum wallisii, Dieffenbachia and Monstera adansonii ) grown hydroponically under controlled conditions were used to systematically quantify VOC removal by the leaves, whole cuttings and roots. Acetone, toluene, α-pinene, o-xylene, and limonene were selected as model indoor air pollutants. The results showed a marked variability in the leaf-based VOC removal efficiency among the plant species and pollutant, but complete VOC removal was never obtained. However, the whole plant cuttings supported complete and rapid (20-115 h) removals of all VOCs. Finally, the root-associated microorganisms were shown to significantly contribute to VOC removal, mainly through rhizodegradation. Overall, this study suggest that VOC removal by plant cuttings is due to the combined effects of physical adsorption and metabolic degradation mediated by plants and microorganisms, highlighting the synergistic role of plant morphological traits and rhizospheric microbial communities in phytoremediation.