A hybrid catalytic hydrogenation/membrane distillation process for nitrogen resource recovery from nitrate-contaminated waste ion exchange brine
| Autor: | Timothy J. Strathmann, Johan Vanneste, Tzahi Y. Cath, Xiangchen Huo |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Ammonium sulfate
Environmental Engineering Nitrogen 0208 environmental biotechnology chemistry.chemical_element 02 engineering and technology 010501 environmental sciences Membrane distillation 01 natural sciences Ammonia chemistry.chemical_compound Brining Nitrate Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering Resource recovery Distillation Nitrates Ion exchange Chemistry Ecological Modeling Pulp and paper industry Pollution 020801 environmental engineering Ion Exchange Salts Hydrogenation |
| Zdroj: | Water research. 175 |
| ISSN: | 1879-2448 |
| Popis: | Ion exchange is widely used to treat nitrate-contaminated groundwater, but high salt usage for resin regeneration and management of waste brine residuals increase treatment costs and add environmental burdens. Development of palladium-based catalytic nitrate treatment systems for brine treatment and reuse has showed promising activity for nitrate reduction and selectivity towards the N2 over the alternative product ammonia, but this strategy overlooks the potential value of nitrogen resources. Here, we evaluated a hybrid catalytic hydrogenation/membrane distillation process for nitrogen resource recovery during treatment and reuse of nitrate-contaminated waste ion exchange brines. In the first step of the hybrid process, a Ru/C catalyst with high selectivity towards ammonia was found to be effective for nitrate hydrogenation under conditions representative of waste brines, including expected salt buildup that would occur with repeated brine reuse cycles. The apparent rate constants normalized to metal mass (0.30 ± 0.03 mM min−1 gRu−1 under baseline condition) were comparable to the state-of-the-art bimetallic Pd catalyst. In the second stage of the hybrid process, membrane distillation was applied to recover the ammonia product from the brine matrix, capturing nitrogen as ammonium sulfate, a commercial fertilizer product. Solution pH significantly influenced the rate of ammonia mass transfer through the gas-permeable membrane by controlling the fraction of free ammonia species (NH3) present in the solution. The rate of ammonia recovery was not affected by increasing salt levels in the brine, indicating the feasibility of membrane distillation for recovering ammonia over repeated reuse cycles. Finally, high rates of nitrate hydrogenation (apparent rate constant 1.80 ± 0.04 mM min−1 gRu−1) and ammonia recovery (overall mass transfer coefficient 0.20 m h−1) with the hybrid treatment process were demonstrated when treating a real waste ion exchange brine obtained from a drinking water utility. These findings introduce an innovative strategy for recycling waste ion exchange brine while simultaneously recovering potentially valuable nitrogen resources when treating contaminated groundwater. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect