Evaluation of CO2 Fixation by Enhanced Weatherin

Importance of the Topic

Removing CO2 from the atmosphere through negative emissions technologies is essential to meet climate goals. Enhanced weathering transforms silicate or carbonate minerals into stable carbonates, permanently fixing CO2. Reliable quantitation of inorganic carbon in solid samples underpins evaluation of these methods in both research and industrial monitoring.

Objectives and Study Overview

This study demonstrates a rapid, accurate approach to measure inorganic carbon (IC) in rock and reagent samples using a combined total organic carbon analyzer and solid sample combustion unit. The goal is to quantify CO2 fixed as carbonate to assess enhanced weathering performance.

Methodology and Instrumentation

The analytical setup consists of a TOC-LCPH total organic carbon analyzer coupled with an SSM-5000A solid sample combustion unit. Key measurement parameters include a short cell length, oxygen carrier gas at 500 mL/min, and an IC furnace set to 200 °C. Samples (30–50 mg for standards, up to 1 g for heterogeneous materials) are weighed in boats. Phosphoric acid is dripped onto each sample via an automated dispenser to release CO2. A one-point calibration curve using powdered sodium carbonate (11.3 % C) establishes the response factor.

Main Results and Discussion

The calibration data display linear extraction of CO2 from sodium carbonate. Measurement of calcium carbonate, basic magnesium carbonate, and potassium carbonate yielded IC concentrations of 12.2 %, 10.0 %, and 8.84 %, respectively, with recoveries between 99 % and 102 %. These results confirm high accuracy and reproducibility across different carbonate matrices.

Benefits and Practical Applications of the Method

• Fast analysis time of 6–8 minutes per sample
• Capability to measure up to 1 g of sample, reducing errors from heterogeneity
• Straightforward procedure without extensive sample preparation
• Suitable for assessing CO2 fixation in laboratory and pilot studies of enhanced weathering

Future Trends and Potential Applications

Advancements may include integration with field-deployable analyzers for on-site monitoring, coupling with isotopic measurements to trace carbon sources, and automation for high-throughput screening of geological materials. Expansion into quality control in cement, soil remediation, and mineral processing is anticipated.

Conclusion

The combined TOC-LCPH and SSM-5000A system offers a robust, efficient method to quantify inorganic carbon in solid samples. Its precision and high throughput make it a powerful tool for evaluating CO2 fixation by enhanced weathering and related carbon sequestration technologies.

References

No additional literature references were provided in the original document.