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Article Dans Une Revue Environmental Science and Technology Année : 2023

Long-Term Continuous Test of H 2 -Induced Denitrification Catalyzed by Palladium Nanoparticles in a Biofilm Matrix

Résumé

Pd0 catalysis and microbially catalyzed reduction of nitrate (NO3--N) were combined as a strategy to increase the kinetics of NO3- reduction and control selectivity to N2 gas versus ammonium (NH4+). Two H2-based membrane biofilm reactors (MBfRs) were tested in continuous mode: one with a biofilm alone (H2-MBfR) and the other with biogenic Pd0 nanoparticles (Pd0NPs) deposited in the biofilm (Pd-H2-MBfR). Solid-state characterizations of Pd0NPs in Pd-H2-MBfR documented that the Pd0NPs were uniformly located along the outer surfaces of the bacteria in the biofilm. Pd-H2-MBfR had a higher rate of NO3- reduction compared to H2-MBfR, especially when the influent NO3- concentration was high (28 mg-N/L versus 14 mg-N/L). Pd-H2-MBfR enriched denitrifiers of Dechloromonas, Azospira, Pseudomonas, and Stenotrophomonas in the microbial community and also increased abundances of genes affiliated with NO3--N reductases, which reflected that the denitrifying bacteria could channel their respiratory electron flow to NO3- reduction to NO2-. N2 selectivity in Pd-H2-MBfR was regulated by the H2/NO3- flux ratio: 100% selectivity to N2 was achieved when the ratio was less than 1.3 e- equiv of H2/e- equiv N, while the selectivity toward NH4+ occurred with larger H2/NO3- flux ratios. Thus, the results with Pd-H2-MBfR revealed two advantages of it over the H2-MBfR: faster kinetics for NO3- removal and controllable selectivity toward N2 versus NH4+. By being able to regulate the H2/NO3- flux ratio, Pd-H2-MBfR has significant implications for improving the efficiency and effectiveness of the NO3- reduction processes, ultimately leading to more environmentally benign wastewater treatment.
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Dates et versions

hal-04334062 , version 1 (10-12-2023)

Identifiants

Citer

Jie Cheng, Min Long, Chen Zhou, Zehra-Esra Ilhan, Diana Calvo, et al.. Long-Term Continuous Test of H 2 -Induced Denitrification Catalyzed by Palladium Nanoparticles in a Biofilm Matrix. Environmental Science and Technology, 2023, 57 (32), pp 11948-11957. ⟨10.1021/acs.est.3c01268⟩. ⟨hal-04334062⟩
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