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Increasing concentrations of carbon dioxide in the atmosphere will inevitably lead to long-term changes in climate that can have serious consequences. Controlling anthropogenic emission of carbon dioxide into the atmosphere, however, represents a significant technological challenge. Various chemical approaches have been suggested, perhaps the most promising of these is based

Increasing concentrations of carbon dioxide in the atmosphere will inevitably lead to long-term changes in climate that can have serious consequences. Controlling anthropogenic emission of carbon dioxide into the atmosphere, however, represents a significant technological challenge. Various chemical approaches have been suggested, perhaps the most promising of these is based on electrochemical trapping of carbon dioxide using pyridine and derivatives. Optimization of this process requires a detailed understanding of the mechanisms of the reactions of reduced pyridines with carbon dioxide, which are not currently well known. This thesis describes a detailed mechanistic study of the nucleophilic and Bronsted basic properties of the radical anion of bipyridine as a model pyridine derivative, formed by one-electron reduction, with particular emphasis on the reactions with carbon dioxide. A time-resolved spectroscopic method was used to characterize the key intermediates and determine the kinetics of the reactions of the radical anion and its protonated radical form. Using a pulsed nanosecond laser, the bipyridine radical anion could be generated in-situ in less than 100 ns, which allows fast reactions to be monitored in real time. The bipyridine radical anion was found to be a very powerful one-electron donor, Bronsted base and nucleophile. It reacts by addition to the C=O bonds of ketones with a bimolecular rate constant around 1* 107 M-1 s-1. These are among the fastest nucleophilic additions that have been reported in literature. Temperature dependence studies demonstrate very low activation energies and large Arrhenius pre-exponential parameters, consistent with very high reactivity. The kinetics of E2 elimination, where the radical anion acts as a base, and SN2 substitution, where the radical anion acts as a nucleophile, are also characterized by large bimolecular rate constants in the range ca. 106 - 107 M-1 s-1. The pKa of the bipyridine radical anion was measured using a kinetic method and analysis of the data using a Marcus theory model for proton transfer. The bipyridine radical anion is found to have a pKa of 40±5 in DMSO. The reorganization energy for the proton transfer reaction was found to be 70±5 kJ/mol. The bipyridine radical anion was found to react very rapidly with carbon dioxide, with a bimolecular rate constant of 1* 108 M-1 s-1 and a small activation energy, whereas the protonated radical reacted with carbon dioxide with a rate constant that was too small to measure. The kinetic and thermodynamic data obtained in this work can be used to understand the mechanisms of the reactions of pyridines with carbon dioxide under reducing conditions.
ContributorsRanjan, Rajeev (Author) / Gould, Ian R (Thesis advisor) / Buttry, Daniel A (Thesis advisor) / Yarger, Jeff (Committee member) / Seo, Dong-Kyun (Committee member) / Arizona State University (Publisher)
Created2015
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We analyze current approaches to carbon accounting for removed carbon sold on carbon markets, focusing on carbon crediting under the framing of a remaining carbon budget, the issue of durability, and approaches to accounting methodologies. We explore the topic of mixing carbon with other problems in developing carbon accounting methodologies

We analyze current approaches to carbon accounting for removed carbon sold on carbon markets, focusing on carbon crediting under the framing of a remaining carbon budget, the issue of durability, and approaches to accounting methodologies. We explore the topic of mixing carbon with other problems in developing carbon accounting methodologies and highlight the open policy questions. We conclude with a suggested framework for accounting for carbon removal accounting that simplifies climate action and enables a world with negative carbon emissions.

ContributorsArcusa, Stéphanie (Author) / Lackner, Klaus (Author) / Page, Robert (Author) / Sriramprasad, Vishrudh (Author) / Hagood, Emily (Author) / Center for Negative Carbon Emissions (Contributor)
Created2022-11-01
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Description

This document details a conceptual Framework for the Certification of Carbon Sequestration (FCCS). It is based on a system designed to support negative emissions. It provides the minimum requirements for the development of carbon sequestration standards and certificates of carbon sequestration. It allows the certification of standards so that they

This document details a conceptual Framework for the Certification of Carbon Sequestration (FCCS). It is based on a system designed to support negative emissions. It provides the minimum requirements for the development of carbon sequestration standards and certificates of carbon sequestration. It allows the certification of standards so that they in turn produce certification of removed carbon that authenticates durability and verifiability. The framework (i) identifies an organizational structure for the certification system, (ii) clarifies the responsibility of participating entities, (iii) provides certificate designs and usages, (iv) details the requirements to develop measurement protocols, (v) provides mechanisms to support a long-term industry, and (vi) outlines a vision towards durable storage.

ContributorsArcusa, Stéphanie (Author) / Lackner, Klaus (Author) / Hagood, Emily (Author) / Page, Robert (Author) / Sriramprasad, Vishrudh (Author)
Created2022-12-05
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Description

Carbon Dioxide Removal (CDR) is essential to meet the Paris Agreement’s commitment to stay below a 1.5 degrees Celsius average temperature increase. To provide critical foundational support to the development, deployment, and scaling of CDR, certification of carbon removal is needed. The international community is developing rules for the functioning

Carbon Dioxide Removal (CDR) is essential to meet the Paris Agreement’s commitment to stay below a 1.5 degrees Celsius average temperature increase. To provide critical foundational support to the development, deployment, and scaling of CDR, certification of carbon removal is needed. The international community is developing rules for the functioning of carbon markets. To support that process, we explored open questions on four key themes in the development of standards and certification of carbon removal through an international multi-stakeholder consultation process hosted by the Global Carbon Removal Partnership, Arizona State University, and Conservation International. Categories of stakeholders included standard developing organizations, non-governmental organizations, governments, and academics. Discussions covered 1. the treatment of emission reduction, avoidance,and removal in certification, 2. the role of additionality in carbon removal, 3. the choice of certification instrument for carbon removal, and 4. the treatment of durability in certification. They revealed fundamental differences in viewpoints on how certification should work. We highlight areas of further exploration, concluding that providing transparency on assumptions made at the certification level will be crucial to progress and, eventually, the acceptance and success of carbon removal as a climate solution.

ContributorsArcusa, Stéphanie (Author) / Sprenkle-Hyppolite, Starry (Author) / Agrawal, Aditya (Author)
Created2022-11-09
ContributorsKealoha, Alisia (Author) / Adamson, Joni (Thesis director) / Arcusa, Stéphanie (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor)
Created2024-05
ContributorsKealoha, Alisia (Author) / Adamson, Joni (Thesis director) / Arcusa, Stéphanie (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor)
Created2024-05
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Description

A brief describing how certificates of carbon sequestration ought to work, their meaning, and their requirements.

ContributorsArcusa, Stéphanie (Author) / Lackner, Klaus S (Author)
Created2021
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Description

Workshop report of general outcomes from stakeholder discussions regarding the planning of the decarbonization of the state of Arizona as part of a regional effort.

Created2021-09
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Description

Workshop report on socio-economic and technical discussions Direct Air Capture as a technology for the climate transition.

Created2022-01-19