Efficient toluene degradation using Bacillus subtilis biofilm-supported Mn–Ce/zeolite catalysts
This study investigated a new approach for synthesizing Bacillus subtilis biofilm-supported Mn–Ce/zeolite catalysts for the degradation of gaseous toluene. Four different metal oxide nano-catalysts (ZMn, ZMnCe-10 %, ZMnCe-20 %, and ZMnCe-30 %) were synthesized with varying ratios of manganese (Mn) a...
| Autores: | , , , , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/398132 |
| Acceso en línea: | http://hdl.handle.net/10261/398132 https://api.elsevier.com/content/abstract/scopus_id/85186104083 |
| Access Level: | acceso abierto |
| Palabra clave: | Zeolite CO2 selectivity Engineered Bacillus subtilis biofilm Metal nanoparticles Toluene oxidation zeolites biofilms (microbiology) Bacillus subtilis nanoparticles toluene |
| Sumario: | This study investigated a new approach for synthesizing Bacillus subtilis biofilm-supported Mn–Ce/zeolite catalysts for the degradation of gaseous toluene. Four different metal oxide nano-catalysts (ZMn, ZMnCe-10 %, ZMnCe-20 %, and ZMnCe-30 %) were synthesized with varying ratios of manganese (Mn) and cerium (Ce) on zeolite nanoparticles. TEM, SEM, XRD, BET, XPS, and EDX mapping were used to examine these four samples, as well as simple zeolite. Based on these analyses, the catalytic activity of the prepared samples ZMn, ZMnCe-10 %, ZMnCe-20 %, and ZMnCe-30 % for the complete oxidation of toluene and toluene intermediate products were tested with Non-thermal plasma (NTP) technology in a dielectric barrier discharge (DBD) reactor. Among all, ZMnCe-20 % showed the highest toluene degradation efficiency (89 %) at low concentrations (200 ppm) and humidity (>50 %). Later, highly efficient and hydrophobic nano-biocatalysts were prepared by combining B. subtilis biofilm wild-type (WT) and engineered B. subtilis biofilm EPS with ZMnCe-20 % catalyst. EPS is the main component found in biofilm matrix and plays a key role in influencing properties such as biofilm stability, electron transfer, surface roughness and hydrophobicity. Compared to WT B. subtilis biofilm, EPS overexpressed B. subtilis biofilm showed stronger growth and development on ZMnCe-20 % nanocatalyst. Moreover, the NTP system packed with ZMnCe-20 %/biofilm (EPS+) nano-biocatalyst exhibited the highest toluene degradation activity (99 %) with (83 %) CO<inf>2</inf> selectivity, (up to 50 %) reduction in NOx concentration and complete ozone decomposition at (250 ppm) toluene concentrations and increased humidity (>90 %). High-energy electrons generated in the NTP system break the C–H and C–C bond between the rings of the toluene molecule, forming several byproducts which are later reacted with active radical species such as O[rad], OH[rad], and O<inf>3</inf> and further converted into final degradation products (CO<inf>2</inf> and H<inf>2</inf>O). The results demonstrated successful biofilm development and growth on the ZMnCe-20 % catalyst with advanced features such as superhydrophobicity, H<inf>2</inf>O resistance, improved surface roughness, and electron generation. In short, the study's approach combines bioengineering and material science to develop sustainable nano-biocatalysts for removing VOCs in industrial and environmental settings. |
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