11.Microbial Electrolytic Carbon Capture for Carbon Negative and Energy Positive Wastewater Treatment
机构:Lu Lu , Zhe Huang , Greg H. Rau , and Zhiyong Jason Ren * Departmentof Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States Instituteof Marine Sciences, University of California, Santa Cruz, California 95064, United States
摘要: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鈥?3% 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鈥?5% recovery efficiency, resulting in a net energy gain of 57鈥?2 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.
出版单位:Environmental Science & Technology
作者:郭静 ; 粟晓玲
14.Synergetic Sustainability Enhancement via Utilization of Carbon Dioxide as Carbon Neutral Chemical Feedstock in the Thermo-Chemical Processing of Biomass
机构:Eilhann E. Kwon *, Seong-Heon Cho , and Sungpyo Kim * Departmentof Environment and Energy, Sejong University, Seoul 143-747, South Korea Departmentof Environmental Engineering, Korea University, Sejong-City 339-700, South Korea
出版单位:Environmental Science & Technology
15.碳捕集、利用与封存技术进展与展望 = Carbon capture, utilization and storage progress and prospects
16.Organic Synthesis in the Interstellar Medium by Low-Energy Carbon Irradiation
机构:E. J. McBride , T. J. Millar , and J. J. Kohanoff Atomistic Simulation Centre and Astrophysics Research Centre, Queen鈥檚 University Belfast, Belfast BT7 1NN, Northern Ireland, U.K.
摘要:We present a first principles molecular dynamics (FPMD) study of the interaction of low-energy neutral carbon projectiles with amorphous solid water clusters at 30 K. Reactions involving the carbon atom at an initial energy of 11 and 1.7 eV with 30-molecule clusters have been investigated. Simulations indicate that the formation of hydroxymethylene, an intermediate in formaldehyde production, dominates at the higher energy. The reaction proceeds by fragmenting a water molecule, binding the carbon to the OH radical, and saturating the C valence with a hydrogen atom that can arise from the originally dissociated water molecule, or through a chain of proton transfer events. We identified several possible pathways for the formation of HCOH. When the initial collision occurs at the periphery of the cluster, we observe the formation of CO and the evaporation of water molecules. At the lower energy water fragmentation is not favorable, thus leading to the formation of weakly bound carbon鈥搘ater complexes.
出版单位:Journal of Physical Chemistry A
17.A General Scavenging Rate Constant for Reaction of Hydroxyl Radical with Organic Carbon in Atmospheric Waters
机构:Takemitsu Arakaki , Cort Anastasio , Yukiko Kuroki 搂, Hitomi Nakajima 搂, Kouichirou Okada 搂, Yuji Kotani 搂, Daishi Handa 搂, Sotaro Azechi 搂, Taro Kimura , Ai Tsuhako 搂, and Youichi Miyagi 搂 Department of Chemistry, Biology and Marine Science, Faculty of Science, and 搂Graduate School of Engineering and Science, University of the Ryukyus, 1 Senbaru Nishihara-cho, Okinawa 903-0213, Japan Department of Land, Air and Water Resources, University of California at Davis, One Shields Avenue, Davis, California 95616, United States Okinawa Environmental Research & Technology Center, 720 Kyozuka, Urasoe-city, Okinawa, 901-2111, Japan
摘要:Hydroxyl radical (OH) is an important oxidant in atmospheric aqueous phases such as cloud and fog drops and water-containing aerosol particles. We find that numerical models nearly always overestimate aqueous hydroxyl radical concentrations because they overpredict its rate of formation and, more significantly, underpredict its sinks. To address this latter point, we examined OH sinks in atmospheric drops and aqueous particles using both new samples and an analysis of published data. Although the molecular composition of organic carbon, the dominant sink of OH, is extremely complex and poorly constrained, this sink behaves very similarly in different atmospheric waters and even in surface waters. Thus, the sink for aqueous OH can be estimated as the concentration of dissolved organic carbon multiplied by a general scavenging rate constant [kC,OH = (3.8 卤 1.9) 脳 108 L (mol C)鈭? s鈥?], a simple process that should significantly improve estimates of OH concentrations in atmospheric drops and aqueous particles.
出版单位:Environmental Science & Technology (ES&T)
18.A Graphical Approach for Pinch-Based Source鈥揝ink Matching and Sensitivity Analysis in Carbon Capture and Storage Systems
机构:Joseph Angelo R. Diamante , Raymond R. Tan , Dominic C. Y. Foo , Denny K. S. Ng , Kathleen B. Aviso , and Santanu Bandyopadhyay 搂 Chemical Engineering Department/Center for Engineering and Sustainable Development Research, De La Salle University, 2401 Taft Avenue, 1004 Manila, Philippines Department of Chemical & Environmental Engineering/Centre of Excellence for Green Technologies, University of Nottingham, Malaysia, 43500 Semenyih, Selangor, Malaysia搂 Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
摘要:Carbon capture and storage (CCS) is regarded as an important interim technology for the reduction of carbon dioxide (CO2) emissions from large industrial facilities such as power plants and refineries. CCS involves capture of concentrated CO2 streams from point sources (industrial flue gases), followed by subsequent secure storage in an appropriate natural reservoir. Such reservoirs include various geological formations such as depleted oil or gas wells, inaccessible coal seams, and saline aquifers. In practice, such storage sites will have limitations on both CO2 storage capacity and injection rate, subject to geological characteristics. In this work, a graphical approach is proposed for matching multiple CO2 sources and storage sites (sinks) optimally within a predefined geographical region. The technique is developed on the basis of analogies with existing graphical pinch analysis approaches for the synthesis of industrial resource conservation networks (RCNs). Generalized principles for optimal CO2 source鈥搒ink matching based on pinch analysis insights are discussed in this work. In addition, sensitivity of the system to the uncertainties that occur in CCS planning (e.g., variation of actual injectivity and capacity as well as options for increase or decrease of source lifetime) is considered. Realistic case studies are shown to illustrate these various aspects of the methodology.
出版单位:Industrial & Engineering Chemistry Research
19.Electrochemical CO2 Capture Using Resin-Wafer Electrodeionization
机构:Saurav Datta , Michael P. Henry , YuPo. J. Lin , Anthony T. Fracaro , Cynthia S. Millard , and Seth W. Snyder * , Energy Systems, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois, United States
摘要:Energy-efficient capture of CO2 from power-plant flue gas is one of the grand challenges to reduce greenhouse gas (GHG) emissions. Current CO2-capture technologies are limited by parasitic energy loss, inefficient capture, and unfavorable process economics. We present a novel electrochemical method for CO2 capture from coal-fired power-plant flue gas. The method utilizes in-situ electrochemical pH control with a resin wafer electrodeionization (RW-EDI) device that continuously shifts the pH of the process fluid between basic and acidic in sequential chambers (pH swing). This pH swing enables capture of CO2 from flue gas in the basic chamber followed by release (recovery) of the captured CO2 (purified) in the acidic chamber of the same device. The approach is based on the sensitivity of the thermodynamic equilibrium of CO2 hydration/dehydration reactions over a narrow pH range. The method enables simultaneous absorption (capture) of CO2 from flue gas and desorption (release) at atmospheric pressure without heating, vacuum, or consumptive chemical usage. In other words, the method concentrates CO2 from 15% in flue gas to >98% in the recovery stream. To the best of our knowledge, this is the first experimental study focusing on simultaneous capture and release (recovery) of CO2 using an electrochemical method. We describe the method, the role of operating parameters on CO2 recovery, and advancements in process design and engineering for improved efficiency. We report on a method to enhance gas/liquid mixing inside the RW-EDI, which significantly increased CO2 capture rates. We also discuss the importance of using an enzyme/catalyst in enhancing the reaction kinetics. CO2 capture was observed to be a strong function of gas and liquid flow rates and applied electrical field. Up to 80% of the CO2 was captured from a simulated flue gas stream with >98% purity. The results indicate that a narrow pH swing from 8 to 6 (near-neutral pH) could offer a viable pathway for energy-efficient CO2 capture if the reaction kinetics are enhanced. Carbonic anhydrase enzyme enhances the reaction kinetics at near-neutral pH; however, the enzyme lost activity due to the instability at the operating conditions. This observation highlighted the necessity of robust enzymes/catalysts to enhance kinetics of CO2 recovery near-neutral pH.
出版单位:Industrial & Engineering Chemistry Research
20.Ab Initio Study of CO2 Capture Mechanisms in Aqueous Monoethanolamine: Reaction Pathways for the Direct Interconversion of Carbamate and Bicarbonate
机构:Yoichi Matsuzaki , Hidetaka Yamada , Firoz A. Chowdhury , Takayuki Higashii , and Masami Onoda Advanced Technology Research Laboratories, Nippon Steel and Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu, Chiba 293-8511, Japan Chemical Research Group, Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
摘要:Ab initio molecular orbital calculations combined with the polarizable continuum model (PCM) formalism have been carried out for a comprehensive understanding of the mechanism of carbon dioxide (CO2) absorption by aqueous amine solutions. CO2 is captured by amines to generate carbamates and bicarbonate. We have examined the direct interconversion pathways of these two species (collectively represented by a reversible hydrolysis of carbamate) with the prototypical amine, monoethanolamine (MEA). We evaluate both a concerted and a stepwise mechanism for the neutral hydrolysis of MEA carbamate. Large activation energies (ca. 36 kcal/mol) and lack of increase in catalytic efficiency with the inclusion of additional water molecules are predicted in both the mechanisms. We also examined the mechanism of alkaline hydrolysis of MEA carbamate at high concentrations of amine (high pH). The addition of OH ion to carbamate anion was theoretically not allowed due to the reduction in the nucleophilicity of the former as a result of microsolvation. We propose an alternative pathway for hydrolysis: a proton transfer from protonated MEA to carbamate to generate the carbamic acid that initially undergoes a nucleophilic addition of OH and subsequent low-barrier reactions leading to the formation of bicarbonate and free MEA. On the basis of the calculated activation energies, this pathway would be the most efficient route for the direct interconversion of carbamate and bicarbonate without the intermediacy of the free CO2, while the actual contributions will be dependent on the concentrations of protonated MEA and OH ions.
出版单位:Journal of Physical Chemistry A

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