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A mineral called serpentine is able to capture carbon dioxide emitted by waste incineration plants and turn it into carbonate.

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Carbon-capturing minerals promise a greener tomorrow

12 Jan 2022

Life cycle assessments show that a technology that captures waste carbon dioxide and turns it into sand may help Singapore reduce its carbon emissions.

From extreme flooding to blazing wildfires, communities around the world continue to be impacted by the snowballing effects of climate change. Taking a stand against the escalating environmental crisis, Singapore has pledged to halve carbon dioxide (CO2) emissions by 2050 as part of the Paris Agreement under the United Nations Framework Convention on Climate Change. But what will it take to meet this ambitious target?

One way to reduce carbon emissions is a process called carbon capture and utilization (CCU). Here, CO2 captured from power plants or factories is collected and funneled into other manufacturing processes. To this end, researchers at A*STAR’s Institute of Chemical & Engineering Sciences (ICES) have patented a CCU technology that makes use of the magnesium-rich mineral serpentine. Once heat-activated, serpentine captures CO2 emitted by waste incineration plants. The end product of this chemical reaction, known as CO2 mineralization, is carbonate, which can be used in construction as a sand alternative.

Given the promise of CO2 mineralization technology, Zi-Yu Khoo from A*STAR’s Singapore Institute of Manufacturing Technology (SIMTech), together with colleagues from the Institute of Material Research and Engineering (IMRE) and ICES set out to investigate the feasibility of using this CCU approach to help Singapore curtail its carbon emissions.

The team performed a life cycle assessment of CO2 mineralization starting from the mining and transport of serpentine to the end-stage production of the sand alternative. “Carbon emissions along the entire life cycle or supply chain were considered, to evaluate net carbon abatement of the technology,” explained Khoo.  

The researchers’ analyses revealed that CO2 mineralization indeed offers Singapore the ability to effectively capture and repurpose waste CO2 from incineration plants, enabling net carbon abatement. “Additionally, the technology also produces an alternative sand, which could supplement Singapore’s need to import sand for national development,” said Khoo.

However, the researchers note that a few tweaks and optimizations could elevate the potential of this carbon capture technology even further. For example, Khoo recommends that serpentine be sourced from countries close to Singapore to limit long transport distances and to use heat emitted from other industrial processes to power the thermal activation of serpentine.

Ultimately, the team sees these and other carbon abatement methodologies creating a path forward towards a cleaner, greener Singapore with dramatically reduced emissions. “CO2 mineralization as a CCU technology could be considered as a part of a suite of technologies for Singapore to achieve this goal, while contributing to national sustainability and development targets,” concluded Khoo.

Moving forward, Khoo calls for similar life cycle assessments to be performed for other decarbonization strategies to assess, rank and identify the most effective within the context of Singapore.

The A*STAR-affiliated researchers contributing to this research are from the Singapore Institute of Manufacturing Technology (SIMTech), Institute of Material Research and Engineering (IMRE), and Institute of Chemical & Engineering Sciences (ICES).

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References

1. Khoo, Z.Y., Ho, E.H.Z., Li, Y., Yeo, Z., Low, J.S., et al. Life cycle assessment of a CO2 mineralisation technology for carbon capture and utilisation in Singapore. Journal of CO2 Utilization 44, 2-8 (2021) | article
2. J. Bu, T.Y. Yeo, Method and System for Converting Carbon Dioxide into Solid Carbonates, WO/2018/182506, 2019 | article

About the Researcher

Zi-Yu Khoo was a Research Engineer in Sustainability and Life Cycle Engineering at Singapore Institute of Manufacturing Technology (SIMTech). She is currently pursuing a PhD degree in Computer Science at the National University of Singapore, School of Computing, under the A*STAR Graduate Scholarship. Her research interests lie in machine learning for modeling of static and dynamic systems, with applications to the field of sustainability.

This article was made for A*STAR Research by Wildtype Media Group