Here we present information about relevant presentations and publications related to the Passive DAC-project.
Presentations
THE BioCCUS Conference 2026
The project is scheduled to be presented at Klimpo’s next Bio CCUS Conference, ”THE Carbon Capture X-Pedition: Prepping for Transformation”, taking place on 14–15 April 2026.
Link to conference website and follow Klimpo on LinkedIn for updates.
Presentation by Muhammad Nauman Saeed at the 3rd International Conference on Negative CO₂ Emissions, June 2024
From 18–21 June 2024, Muhammad Nauman Saeed*, a doctoral student in Energy Technology at the Department of Space, Earth and Environment, presented the project on a poster at the 3rd International Conference on Negative CO₂ Emissions in Oxford. The poster ”Extraction of Ca from industrial by-products and precipitation of Ca(OH)2 for use in a passive DAC system for negative emissions” showcased an innovative method for extracting calcium from industrial byproducts to produce Ca(OH)₂ using a pH swing process. The concept was well received and generated interest for its innovative approach to negative emissions and circular material use.
* Muhammad Nauman Saeed a, Julian Scheer a, Anna Stedt b, Tobias Mattisson a, Zareen Abbas b, Carl Linderholm a
a Division of Energy Technology, Chalmers University of Technology
b Department of Chemistry and Molecular Biology, Gothenburg University
Carl Linderholm presented innovative research at THE BioCCUS Conferences 2023.
On 4 October 2023, Assistant Professor Carl Linderholm presented the project at THE BioCCUS Conference 2023, held at the Royal Swedish Academy of Engineering Sciences (IVA) in Stockholm. His presentation, titled "Can We Use Waste Materials from Industry for Passive DAC?", explored the potential of industrial byproducts in enabling passive direct air capture of carbon dioxide.
The presentation generated valuable discourse on resource efficiency and circular approaches to carbon removal, highlighting new pathways for leveraging industrial waste in climate-positive solutions.
Publications
Master thesis by Samia Ishaque
Title: “Life Cycle Analysis on the Extraction of Ca(OH)₂ from Industrial Waste Products for Use in a Passive-DAC System for CO₂ Capture” - Master thesis carried out at the Department of Biological and Environmental Sciences at the University of Gothenburg.
Author: Samia Ishaque, Environmental Science.
Short summary: Climate change mitigation is a challenge that requires a two-pronged approach, which is a reduction in Greenhouse gas emissions and the large-scale removal of potent greenhouse gases such as Carbon dioxide (CO₂). Passive Direct Air Capture (Passive DAC) using alkaline minerals presents as a less energy and cost-intensive approach for carbon dioxide removal, particularly when using porous materials produced with alkaline minerals derived from industrial by-products like LD-slag from the steel making industry.
This study evaluates the environmental feasibility of extracting alkaline minerals, specifically Ca(OH)₂, from steel-making by-products (LD-slag) for application in passive DAC systems, using a cradle to gate Life Cycle Assessment (LCA) with a functional unit of 1 tonne of captured CO₂. Two extraction routes for Ca(OH)₂: route 1 using hydrochloric acid (HCl) and route 2 using ammonium chloride (NH₄Cl) were modelled across different environmental impact categories, including climate change, acidification, toxicity, and resource depletion.
Results indicate that the NH₄Cl pathway consistently exhibits about 6-7 times higher impacts than the HCl route across all categories. For both pathways, upstream chemical production, particularly NaOH, HCl, and ammonia, dominates the overall footprint, outweighing impacts from Ca(OH)₂ extraction itself. Transport sensitivity analysis highlights the influence of supply-chain distance, while renewable electricity substitution yields only marginal improvements. In all modelled scenarios, total life-cycle emissions exceed the CO₂ captured, underscoring the trade-offs inherent in Ca(OH)₂ production/extraction for DAC applications.
This ultimately implies that the extraction of Ca(OH)₂ from Industrial waste products for the capture of CO₂ in a passive DAC system is not a viable solution to address industrial waste and reduce atmospheric CO₂ levels.