Acclimatization and real-time performance of botanical biofilters eliminating indoor volatile organic compounds using...

Irrespective of the level of development, people are exposed to a mix of indoor volatile organic compounds (VOCs), including carcinogens such as benzene and formaldehyde. A botanical biofilter (BB) integrates plants, substrates, and their associated microbiomes to eliminate VOCs. Nonetheless, the BB startup time, the impact of indoor conditions, and the contribution of aerial biomass remain insufficiently examined. This work examines the role of acclimatization and varying boundary conditions through real-time VOC quantification. Two BBs (Epipremnum pinnatum) were acclimatized at a constant airflow rate (60 m³ h^-1) to a five-fold concentrated mixture (against maximum guidelines) of priority indoor VOCs with different physicochemical characteristics (BTEX: benzene, toluene, ethylbenzene, xylene; AF: acetaldehyde, formaldehyde) to induce biodegradation. Afterwards, VOCs were reduced to indoor levels (one-fold) in the first BB, and resilience was assessed by interrupting the VOC supply and reactivating. In contrast, the second BB was maintained at five-fold concentration and subjected to varying airflow rates. Results showed that acclimatizing both BBs increased their BTEX removal by 5-fold (max toluene: 0.40 mg_VOC h^-1), shifting from exponential to linear decay. Conversely, AF removal (acetaldehyde and formaldehyde) did not exhibit this shift, and their removal rates were higher (max formaldehyde: 12.73 mg_VOC h^-1). VOC reduction in the first BB, enhanced BTEX removal, and the BB regained performance after shutdown. The second BB demonstrated that while increasing the airflow rate enhanced VOC elimination capacity, the order of airflow application affected performance, along with ongoing acclimatization. Finally, it was verified that foliage organs removed VOCs via plant metabolism.