Microbial Electrolytic Carbon Capture for Carbon Negative and Energy Positive Wastewater Treatment

Lu Lu, Zhe Huang, Greg H. Rau, Zhiyong Jason Ren

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

Energy and carbon neutral wastewater management is a major goal for environmental sustainability, but current progress has only reduced emission rather than using wastewater for active CO2 capture and utilization. We present here a new microbial electrolytic carbon capture (MECC) approach to potentially transform wastewater treatment to a carbon negative and energy positive process. Wastewater was used as an electrolyte for microbially assisted electrolytic production of H2 and OH- at the cathode and protons at the anode. The acidity dissolved silicate and liberated metal ions that balanced OH-, producing metal hydroxide, which transformed CO2 in situ into (bi)carbonate. Results using both artificial and industrial wastewater show 80-93% of the CO2 was recovered from both CO2 derived from organic oxidation and additional CO2 injected into the headspace, making the process carbon-negative. High rates and yields of H2 were produced with 91-95% recovery efficiency, resulting in a net energy gain of 57-62 kJ/mol-CO2 captured. The pH remained stable without buffer addition and no toxic chlorine-containing compounds were detected. The produced (bi)carbonate alkalinity is valuable for wastewater treatment and long-term carbon storage in the ocean. Preliminary evaluation shows promising economic and environmental benefits for different industries. (Figure Presented).

Original languageEnglish (US)
Pages (from-to)8193-8201
Number of pages9
JournalEnvironmental Science and Technology
Volume49
Issue number13
DOIs
StatePublished - Jul 7 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

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