Electrocatalytic Upcycling of Nitrate Wastewater into an Ammonia Fertilizer via an Electrified Membrane

Jianan Gao, Ning Shi, Yifan Li, Bo Jiang, Taha Marhaba, Wen Zhang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Electrochemically upcycling wastewater nitrogen such as nitrate (NO3-) and nitrite (NO2-) into an ammonia fertilizer is a promising yet challenging research topic in resource recovery and wastewater treatment. This study presents an electrified membrane made of a CuO@Cu foam and a polytetrafluoroethylene (PTFE) membrane for reducing NO3- to ammonia (NH3) and upcycling NH3 into (NH4)2SO4, a liquid fertilizer for ready-use. A paired electrolysis process without external acid/base consumption was achieved under a partial current density of 63.8 ± 4.4 mA·cm-2 on the cathodic membrane, which removed 99.9% NO3- in the feed (150 mM NO3-) after a 5 h operation with an NH3 recovery rate of 99.5%. A recovery rate and energy consumption of 3100 ± 91 g-(NH4)2SO4·m-2·d-1 and 21.8 ± 3.8 kWh·kg-1-(NH4)2SO4, respectively, almost outcompete the industrial ammonia production cost in the Haber-Bosch process. Density functional theory (DFT) calculations unraveled that the in situ electrochemical conversion of Cu2+ into Cu1+ provides highly dynamic active species for NO3- reduction to NH3. This electrified membrane process was demonstrated to achieve synergistic nitrate decontamination and nutrient recovery with durable catalytic activity and stability.

Original languageEnglish (US)
Pages (from-to)11602-11613
Number of pages12
JournalEnvironmental Science and Technology
Volume56
Issue number16
DOIs
StatePublished - Aug 16 2022

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

Keywords

  • ammonia recovery
  • electrified membrane flow-cell
  • nitrate reduction
  • paired electrolysis method
  • separation science

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