Category: Scientific Theses

Scientific Theses

Amini Khoei (2025): Life Cycle and Economic assessment of CO₂ mineralization pathways in Austria – Thesis

Mahmoud Amini Khoei, IN: TU Wien, https://doi.org/10.34726/hss.2025.119627

In Austria, annual CO₂ emissions are approximately 73 million tons, significantly contributing to greenhouse gas concentrations. This study evaluates the environmental and economic feasibility of two carbon mineralization processes in Austria: (1) the utilization of biogenic CO₂ from biogas upgrading with recycled concrete aggregates (RCA), and (2) the carbonation of steel slag using process-generated CO₂ from steel production. A combined life cycle assessment (LCA) and techno-economic analysis (TEA) framework was applied to assess these processes, focusing on key operational parameters such as RCA particle size, CO₂ delivery pressure, and electricity sources.

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Scientific Theses

PhD-thesis: Mineral Carbonation Potential and Transition Metal Migration in Kimberlite and Ultramafic Rocks: An Integrated Study of Acid Leaching, Enhanced Rock Weathering, and Microbial CO2 Sequestration

Baolin Wang, University of Alberta, https://doi.org/10.7939/r3-b743-cx81

Carbonation of mafic and ultramafic rocks and mineral wastes provides a permanent way to sequester excess atmospheric CO2. Recent research has shown that this method also offers the potential for enhanced recovery of critical metals from mine tailings. This thesis presents a comprehensive study on the potential for CO2 sequestration through the carbonation of ultramafic rocks and mineral wastes from diamond mines. Utilizing a variety of analytical and experimental methods, this research aims to enhance our understanding of mineral carbonation processes and their application in offsetting CO2 emissions, while also exploring the recovery of critical metals from mine tailings.

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Scientific Theses

PhD-thesis: Exploring the applicability of amine-containing metal-organic frameworks on direct air capture of carbon dioxide

Shreya Mahajan, University of Jyväskylä, http://urn.fi/URN:ISBN:978-952-86-0280-4

The thesis’s first section covers the most recent achievements made in developing MOFs for DAC potential. It provides a detailed account of structural approaches, examines MOFs’ DAC performance under different conditions, and discusses the CO2 adsorption pathways. The second section of the thesis encapsulates the key results published in three journal articles related to this work. The results and discussion section detail the preparation of an amino-triazole-based N-rich bent ligand and the structural determination of its sixteen new molecular salts, each assisted by different anions. Several characterization techniques were employed to fully understand these anion-templated supramolecular assemblies, which are self-assembled by a combination of noncovalent interactions, constituting different protonation sites and a versatile spectrum of conformations of the bent ligand.

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Scientific Theses

PhD-thesis: Missing Paths to Justice: The Knowledge Politics of Carbon Dioxide Removal

Natalia Rubiano, Lund University Centre for Sustainability Studies, https://portal.research.lu.se/en/publications/missing-paths-to-justice-the-knowledge-politics-of-carbon-dioxide

CDR has become a central component in the climate change mitigation scenarios assessed by the IPCC. These scenarios rely on the large-scale deployment of BECCS and Afforestation to keep global average temperatures below 2°C of warming, despite substantial concerns about their feasibility, scalability, and unwanted impacts.
In this thesis, a critical examination of policy-relevant knowledge production and its effects is provided, by scrutinizing CDR as the most recent manifestation of the politics of knowledge in climate change mitigation research. 

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Scientific Theses

PhD-thesis: Using Capacitive Deionization for Direct Air Capture of Carbon Dioxide: Theory and Demonstration of the Bicarbonate-Enriched Alkalinity Concentration Swing

Andrew Bergman, Havard University, https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37377928

This thesis introduces a framework for a new solvent-based DAC approach, the bicarbonate-enriched alkalinity concentration swing (BE-ACS), and demonstrates how the two key steps of the BE-ACS cycle, bicarbonate selection and concentration, can be experimentally implemented using membrane capacitive deionization (MCDI) technology. 

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Scientific Theses

Master’s thesis: Social Marginal Abatement Cost of Negative Emissions: Incorporating Externalities into the Private Costs of Carbon Dioxide Removal

Anna Havukainen, University of Helsinki, http://urn.fi/URN:NBN:fi:hulib-202404091663

The objective of this thesis was to identify the Negative Emission Technologies and Practices (NETPs) that yield the lowest social costs, thereby providing insights into which NETPs should be prioritized for investments in CDR. This evaluation was conducted by developing a Social Marginal Abatement Cost Curve (SMACC) framework, to examine the potentials and social costs of various NETPs. 

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Scientific Theses

PhD-thesis: Concentrating Alkalinity for Direct Air Capture of Carbon Dioxide: Using Osmotic Pressure for Concentration and Separation

Anatoly Rinberg, Harvard University, https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37377926

First, the author proposes a new approach for removing atmospheric CO2, the alkalinity concentration swing (ACS), driven by concentrating and diluting aqueous alkaline solution, which increases and decreases the partial pressure of CO2 of the solution, respectively. Second, he improves on the ACS process by introducing a selectivity step, which separates bicarbonate ions from carbonate ions. A theoretical investigation reveals that bicarbonate-enrichment allows for reaching higher cycle capacity, higher CO2 partial pressure, and improved absorption rates. Third, nanofiltration is experimentally studied, and confirmed as a mechanism to enrich bicarbonate ions, reaching bicarbonate-carbonate selectivity factors above 30. Fourth, he experimentally demonstrates the ability to use reverse osmosis, a membrane-based separation process driven by applied pressure, as a method for concentrating alkalinity.

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Scientific Theses

PhD-Thesis: Ocean Alcalinity Enhancement: Tool to Mitigate Climate Change

Jakob Bang Rønning, University of Southern Denmark, https://doi.org/10.21996/p2f3-rp88

This thesis explores the potential of ocean alkalinity enhancement as an ocean-based carbon dioxide removal method, specifically focusing on alkaline minerals for mineral-based OAE as novel avenues for climate change mitigation. As global decarbonization is obliged, integrating diverse CDR technologies is essential to effectively counter and reverse the ongoing trend of global CO2 emissions in the atmosphere. This thesis studied the nuanced aspects of mineral-based OAE, emphasizing the potential of alkaline minerals such as dolomite, limestone, and olivine. The study aims to examine their impact on seawater carbon chemistry and primary producers. 

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Scientific Theses

Master thesis: Potential analysis of the integration of flexibly operated Direct Air Capture (DAC) plants in the heat and power system using the example of Hamburg

Moritz Rickert, Hamburg University of Applied Sciences, http://hdl.handle.net/20.500.12738/14920

For climate neutrality by 2045, Germany must compensate unavoidable residual greenhouse gas emissions by negative emission technologies such as direct air capture technology. This study explores the technical feasibility and economic viability of implementing flexibly operated DAC plants in Hamburg’s district heating system in 2045.

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Scientific Theses

Licentiate thesis: Modeling the Potential for Carbon Removal in Agriculture: Integrating Farmer Perspectives

Andreas Rehn, Chalmers Universtiy of Technology

The overarching aim of this thesis is to provide insights into the dynamic processes governing SOC stocks and to identify viable paths for agricultural systems to contribute to climate change mitigation. By integrating current scientific knowledge of carbon sequestration in agriculture with feasible agricultural applications, this work proposes local realistic strategies for enhancing soil organic carbon and presents a quantitative assessment of their potential for CO2 removal.

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