RT info:eu-repo/semantics/doctoralThesis
T1 Biotechnologies for indoor air treatment: Development of novel bioactive coating-based bioreactors for indoor VOC treatment
A1 González Martín, Javier
A2 Universidad de Valladolid. Escuela de Doctorado
K1 Bioactivos
K1 Bioactive coating
K1 Recubrimiento bioactivo
K1 Biofiltration
K1 Biofiltración
K1 Volatile organic compounds
K1 Compuestos orgánicos volátiles
K1 Indoor air
K1 Aire de interior
K1 3308 Ingeniería y Tecnología del Medio Ambiente
AB Air pollution constitutes a significant threat to human health. More specifically, indoor air represents an increasing hazard due to the amount of time spent in enclosed environments and the potential accumulation of contaminants. Traditional physical-chemical air purification technologies, while effective in removing particulate matter, exhibit limitations in eliminating volatile organic compounds (VOCs) and often generate harmful by-products. In this context, biotechnologies based on contaminant-degrading microorganisms emerge as a promising alternative, though they also face challenges such as mass transfer limitations and implementation in compact spaces.This thesis focuses on the development and evaluation of bioactive coatings as an innovative technology for indoor air purification. These coatings consist of a porous polymeric matrix that limits water content, thereby enhancing the transfer of hydrophobic contaminants. Additionally, they offer other advantages, such as higher microbial density and versatility in application.Initially, bioactive coatings were designed and tested in small-scale bioreactors using toluene, n-hexane, trichloroethylene (TCE), and α-pinene as model contaminants. The results demonstrated efficiencies exceeding 90% in the removal of toluene and pinene, while the removal of TCE and hexane was low (<30%) due to transfer limitations. The importance of an adequate supply of water and nutrients to sustain microbial activity was highlighted, along with the robustness of the coatings under high contaminant loads.Subsequently, bioactive coatings applied to porous lava rock were used as the packing material of bioreactors and compared to conventional bioreactors. Both systems achieved high removal rates of toluene and pinene at residence times greater than 60 seconds, though efficiency significantly declined at shorter residence times. Pre-acclimation of the biomass proved critical for enhanced performance, and the bioactive coatings were shown to be comparable to traditional systems, emphasizing their feasibility for continuous and sustainable applications.In a similar experiment, bioactive coatings on polyurethane foam were evaluated as packing material. Average removal rates exceeded 60% for hexane, 90% for toluene, and 80% for pinene in the conventional bioreactor, while bioactive coatings exhibited slightly lower performance. The outcomes depended on residence time and operational conditions, underscoring the importance of prior adaptation of the microbial community.To optimize the composition of the bioactive coatings, a new experiment was conducted incorporating additives such as halloysite nanotubes (HNTs) and sucrose-glycerol mixtures (Suc/Gly) to evaluate toluene removal. At low toluene concentrations, all coatings achieved complete removal within 24 hours, while at higher concentrations, coatings with low HNT concentrations exhibited superior performance. Surface analyses of the bioactive coatings confirmed the presence of porous structures.Finally, the bioactive coatings with the optimized composition were used as packing material of a bioreactor, assessing the toluene removal capacity. After adjusting the operating conditions, toluene removal rates reached 78% in the bioactive coating bioreactor, surpassing the conventional bioreactor. Efficiency declined due to microbial overgrowth, which covered the coating surface. The addition of silicone oil improved toluene transfer, resulting in increased removal rates.In conclusion, bioactive coatings demonstrated their viability and sustainability as a technology for VOC removal, offering a more efficient and environmentally friendly alternative to traditional technologies. This research represents a significant advancement towards improving indoor air quality through innovative biotechnologies.
YR 2025
FD 2025
LK https://uvadoc.uva.es/handle/10324/75897
UL https://uvadoc.uva.es/handle/10324/75897
LA eng
NO Escuela de Doctorado
DS UVaDOC
RD 13-jul-2025