Dataset Information

Olivine Dissolution in Seawater: Implications for CO₂ Sequestration through Enhanced Weathering in Coastal Environments.

ABSTRACT: Enhanced weathering of (ultra)basic silicate rocks such as olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine weathering is expected to increase seawater alkalinity, thus resulting in additional CO₂ uptake from the atmosphere. However, the mechanisms of marine olivine weathering and its effect on seawater-carbonate chemistry remain poorly understood. Here, we present results from batch reaction experiments, in which forsteritic olivine was subjected to rotational agitation in different seawater media for periods of days to months. Olivine dissolution caused a significant increase in alkalinity of the seawater with a consequent DIC increase due to CO₂ invasion, thus confirming viability of the basic concept of enhanced silicate weathering. However, our experiments also identified several important challenges with respect to the detailed quantification of the CO₂ sequestration efficiency under field conditions, which include nonstoichiometric dissolution, potential pore water saturation in the seabed, and the potential occurrence of secondary reactions. Before enhanced weathering of olivine in coastal environments can be considered an option for realizing negative CO₂ emissions for climate mitigation purposes, these aspects need further experimental assessment.

SUBMITTER: Montserrat F

PROVIDER: S-EPMC5382570 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature

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Olivine Dissolution in Seawater: Implications for CO<sub>2</sub> Sequestration through Enhanced Weathering in Coastal Environments.

Montserrat Francesc F Renforth Phil P Hartmann Jens J Leermakers Martine M Knops Pol P Meysman Filip J R FJ

Environmental science & technology 20170320 7

Enhanced weathering of (ultra)basic silicate rocks such as olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine weathering is expected to increase seawater alkalinity, thus resulting in additional CO<sub>2</sub> uptake from the atmosphere. However, the mechanisms of marine olivine weathering and its effect on seawater-carbonate chemistry remain poorly understood. Here, we present results from batch reaction experim ...[more]

PMID: 28281750

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Project description:Coastal enhanced weathering (CEW) is a carbon dioxide removal (CDR) approach whereby crushed silicate minerals are spread in coastal zones to be naturally weathered by waves and tidal currents, releasing alkalinity and removing atmospheric carbon dioxide (CO2). Olivine has been proposed as a candidate mineral due to its abundance and high CO2 uptake potential. A life cycle assessment (LCA) of silt-sized (10 μm) olivine revealed that CEW's life-cycle carbon emissions and total environmental footprint, i.e., carbon and environmental penalty, amount to around 51 kg CO2eq and 3.2 Ecopoint (Pt) units per tonne of captured atmospheric CO2, respectively, and these will be recaptured within a few months. Smaller particle sizes dissolve and uptake atmospheric CO2 even faster; however, their high carbon and environmental footprints (e.g., 223 kg CO2eq and 10.6 Pt tCO2-1, respectively, for 1 μm olivine), engineering challenges in comminution and transportation, and possible environmental stresses (e.g., airborne and/or silt pollution) might restrict their applicability. Alternatively, larger particle sizes exhibit lower footprints (e.g., 14.2 kg CO2eq tCO2-1 and 1.6 Pt tCO2-1, respectively, for 1000 μm olivine) and could be incorporated in coastal zone management schemes, thus possibly crediting CEW with avoided emissions. However, they dissolve much slower, requiring 5 and 37 years before the 1000 μm olivine becomes carbon and environmental net negative, respectively. The differences between the carbon and environmental penalties highlight the need for using multi-issue life cycle impact assessment methods rather than focusing on carbon balances alone. When CEW's full environmental profile was considered, it was identified that fossil fuel-dependent electricity for olivine comminution is the main environmental hotspot, followed by nickel releases, which may have a large impact on marine ecotoxicity. Results were also sensitive to transportation means and distance. Renewable energy and low-nickel olivine can minimize CEW's carbon and environmental profile.

Dataset Information

Olivine Dissolution in Seawater: Implications for CO₂ Sequestration through Enhanced Weathering in Coastal Environments.

Publications

Olivine Dissolution in Seawater: Implications for CO<sub>2</sub> Sequestration through Enhanced Weathering in Coastal Environments.

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Dataset Information

Olivine Dissolution in Seawater: Implications for CO2 Sequestration through Enhanced Weathering in Coastal Environments.

Publications

Olivine Dissolution in Seawater: Implications for CO<sub>2</sub> Sequestration through Enhanced Weathering in Coastal Environments.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Olivine Dissolution in Seawater: Implications for CO₂ Sequestration through Enhanced Weathering in Coastal Environments.