Direct electrolytic dissolution of silicate minerals for air CO 2 mitigation and carbon-negative H 2 production
| Autor: | Roger D. Aines, Michael J. Singleton, Greg H. Rau, William L. Bourcier, Megan M. Smith, Susan A. Carroll |
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| Rok vydání: | 2013 |
| Předmět: |
Carbon Sequestration
Oceans and Seas Bicarbonate Inorganic chemistry PH reduction Electrolyte Sodium Chloride Global Warming Electrolysis law.invention Electrolytes chemistry.chemical_compound law Silicate minerals Seawater Dissolution Minerals Multidisciplinary Silicates Calcium Compounds Carbon Dioxide Silicate Bicarbonates chemistry Physical Sciences Carbon dioxide Thermodynamics Chlorine Acids Hydrogen |
| Zdroj: | Proceedings of the National Academy of Sciences. 110:10095-10100 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1222358110 |
| Popis: | We experimentally demonstrate the direct coupling of silicate mineral dissolution with saline water electrolysis and H 2 production to effect significant air CO 2 absorption, chemical conversion, and storage in solution. In particular, we observed as much as a 10 5 -fold increase in OH − concentration (pH increase of up to 5.3 units) relative to experimental controls following the electrolysis of 0.25 M Na 2 SO 4 solutions when the anode was encased in powdered silicate mineral, either wollastonite or an ultramafic mineral. After electrolysis, full equilibration of the alkalized solution with air led to a significant pH reduction and as much as a 45-fold increase in dissolved inorganic carbon concentration. This demonstrated significant spontaneous air CO 2 capture, chemical conversion, and storage as a bicarbonate, predominantly as NaHCO 3 . The excess OH − initially formed in these experiments apparently resulted via neutralization of the anolyte acid, H 2 SO 4 , by reaction with the base mineral silicate at the anode, producing mineral sulfate and silica. This allowed the NaOH, normally generated at the cathode, to go unneutralized and to accumulate in the bulk electrolyte, ultimately reacting with atmospheric CO 2 to form dissolved bicarbonate. Using nongrid or nonpeak renewable electricity, optimized systems at large scale might allow relatively high-capacity, energy-efficient (2 captured), and inexpensive (2 mitigated) removal of excess air CO 2 with production of carbon-negative H 2 . Furthermore, when added to the ocean, the produced hydroxide and/or (bi)carbonate could be useful in reducing sea-to-air CO 2 emissions and in neutralizing or offsetting the effects of ongoing ocean acidification. |
| Databáze: | OpenAIRE |
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