Thesis
Assessing the carbon capture potential of silicate materials with different soils and organic supplements
Southern Cross University
Masters by Thesis, Southern Cross University
2023
DOI:
https://doi.org/10.25918/thesis.362
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Abstract
Enhanced weathering is a promising technology for carbon sequestration. The process involves the addition, and subsequent dissolution, of certain silicate materials which increases total alkalinity (TA) in soils. To date, there is a considerable research gap regarding the interaction between different soil types, various silicate materials, and organic matter. Furthermore, only a handful of silicate materials have been assessed for their weathering capacity, and different measurement methodologies have been utilised. In general, most studies use a measured alkalinity increase to calculate subsequent CO2 sequestration and ignore dissolved inorganic carbon (DIC) dynamics, which influences uptake potential.
To close these knowledge gaps, this study compared the dissolution rates of 6 different silicate materials, including by-products of different industries such as basalt fines, fly ash and slag, in pure water. Then, the dissolution of three of these minerals was assessed in four different Australian soil types by measuring the changes in TA, DIC, total inorganic carbon, and total organic carbon. In a second experiment, the interaction of organic matter in soils, both raw and carbonised, with alkalinity generating basalt was assessed in soil columns.
One of the primary outcomes from the dissolution experiment was that basalt and iron slag were the two silicate materials with the highest dissolution rate per mass of feedstock. The incubation experiments in soils showed that the soil type strongly influences the enhanced weathering capacity of silicate materials. In particular, the soil pH and cation exchange capacity were important factors in regulating the dissolution of silicates in soil. The column experiment with silicate materials (basalt) and organic wastes (ryegrass and tannery waste, or hydrochar) showed that alkaline basalt added with the organics significantly impacted CO2 production during the experiment (12 weeks), and the addition of ryegrass had a major impact on both the CO2 production and dissolved organic carbon pools.
Finally, this study lists the most critical parameters to analyse and compare prior to and after applying silicate materials in various types of soils.
Details
- Title
- Assessing the carbon capture potential of silicate materials with different soils and organic supplements
- Creators
- Toribio Freije
- Contributors
- Kai G Schulz (Supervisor) - Southern Cross UniversityDirk Erler (Supervisor) - Southern Cross UniversityShane Reid McIntosh (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Masters by Thesis
- Theses
- Masters by Thesis, Southern Cross University
- Publisher
- Southern Cross University
- Number of pages
- xiv, 129
- Identifiers
- 991013187813802368
- Copyright
- © T Freije 2023
- Academic Unit
- Faculty of Science and Engineering
- Resource Type
- Thesis