Catalytic reduction of oxyanions in groundwater in a contactor catalytic membrane reactor
The use of a contactor catalytic membrane reactor (CCMR) has been studied for the chemical reduction of real groundwater spiked with 50 mg/L of NO3− and 200 μg/L of BrO3−. Pd[sbnd]Cu catalysts supported on carbon black (ENS250), commercial carbon nanotubes (CNT), and CNT modified by milling (CNTm) a...
| Authors: | , , , , , , |
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| Format: | article |
| Publication Date: | 2025 |
| Country: | España |
| Institution: | Universidad Autónoma de Madrid |
| Repository: | Biblos-e Archivo. Repositorio Institucional de la UAM |
| Language: | English |
| OAI Identifier: | oai:repositorio.uam.es:10486/719321 |
| Online Access: | http://hdl.handle.net/10486/719321 https://dx.doi.org/10.1016/j.jwpe.2025.107634 |
| Access Level: | Open access |
| Keyword: | Carbon support Contactor catalytic membrane reactor Groundwater Oxyanions Química |
| Summary: | The use of a contactor catalytic membrane reactor (CCMR) has been studied for the chemical reduction of real groundwater spiked with 50 mg/L of NO3− and 200 μg/L of BrO3−. Pd[sbnd]Cu catalysts supported on carbon black (ENS250), commercial carbon nanotubes (CNT), and CNT modified by milling (CNTm) and nitrogen doping (CNTmN) were used to fabricate the catalytic membranes. Complete conversion of BrO3− was achieved with all the catalytic membranes, while very different behaviors were observed for NO3− reduction. Pd-Cu/ENS250 catalytic membranes demonstrated the highest activity (71 %) and higher N2 selectivity (31 %), although NH4+ production could be substantially reduced by lowering the partial pressure of H2 in the CCMR. Membranes based on Pd-Cu/CNT and Pd-Cu/CNTm showed slightly lower activity but much lower selectivity to NH4+ (below 9 %). Moreover, competition between the two oxyanions for active sites was observed, leading to a slight loss of activity in NO3− reduction and an increase in NH4+ selectivity. Testing the catalytic membranes with both deionized water and real groundwater demonstrated the influence of inorganic salts commonly found in groundwater (HCO3−, Cl−, and SO42−) and organic matter. Although some decrease in activity and an increase in NH4+ selectivity was observed for real groundwater, the catalytic membranes maintained high stability over 5 successive reaction cycles. NO3− conversions close to 60 %, with NH4+ selectivity values around 5 and 9 %, were achieved, along with complete BrO3− conversion, ensuring compliance with water standards |
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