Chromium isotope fractionation during Cr(VI) reduction in a methane-based hollow-fiber membrane biofilm reactor
| Autor: | Liping Qin, Guojun Chen, Ya-Nan Bai, Yong-Ze Lu, Raymond J. Zeng, Liang Fu |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Chromium
Geologic Sediments Environmental Engineering chemistry.chemical_element Fractionation Chemical Fractionation 010501 environmental sciences 010502 geochemistry & geophysics 01 natural sciences Methane chemistry.chemical_compound Bioreactors Adsorption Isotope fractionation Chromium Isotopes Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering Aqueous solution Bacteria Membrane reactor Ecological Modeling Pollution chemistry Biofilms Environmental chemistry Anaerobic oxidation of methane Oxidation-Reduction Water Pollutants Chemical |
| Zdroj: | Water Research. 130:263-270 |
| ISSN: | 0043-1354 |
| DOI: | 10.1016/j.watres.2017.11.045 |
| Popis: | Chromium (Cr) isotope fractionation analysis is a promising tool for monitoring Cr(VI) reduction in natural aqueous systems. In addition, large amounts of CH4 in natural aqueous sediments are oxidized to CO2 through methanotrophs, thereby mitigating emissions to the atmosphere. However, the investigations on the Cr(VI) reduction process with methanotrophs, and the associated Cr isotope fractionation patterns are scarce. In this study, we have shown that Cr(VI) reduction can occur in the presence of CH4 as the sole electron donor in a hollow-fiber membrane reactor (HfMBR) after direct bacteria enrichment from sediment samples. Products of the methane oxidation by the methanotrophs are used by microbes to reduce Cr(VI) as shown by the progressive increase in δ53Cr with time in the CH4 feed reactor. The isotope fractionation factor (e) of −2.62 ± 0.20‰ was obtained from the application of the Rayleigh distillation model. The results of Cr isotope fractionation analysis also explained the decrease of Cr(VI) concentration in the N2 feed reactor, where the δ53Cr values remained steady in the first two weeks but significantly increased in the last two weeks, indicating that physical adsorption and subsequent Cr(VI) reduction occurred. This study extended the application of Cr isotope fractionation, showing the suitability of this method for clarifying different Cr(VI) removal processes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect